Practice

The Comprehensive Adult Health History

April 16, 2017 Clinical Skills, EHR/EMR, History Taking, Practice No comments , , , ,

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Initial Information

Data and Time of History

The date is always important. Be sure to document the time you evaluate the patient, especially in urgent, emergent, or hospital setitngs.

Identify Data

These include age, gender, marital status, and occupation. The source of history or referral can be the patient, a family member or friend, an officer, a consultant, or the clinical record. Identifying the source of referral helps you assess the quality of the referral information, questions you may need to address in your assessment and written response.

Reliability

Document this information, if relevant. This judgment reflects the quality of the information provided by the patient and is usually made at the end of the interview. For example, “The patient is vague when describing symptoms, and the details are confusing,” or, “The patient is a reliable historian.”

Chief Complaint(s)

Make every attempt to quote the patient’s own words. For example, “My stomach hurts and I feel awful.” If patients have no specific complaints, report their reason for the visit, such as “I have come for my regular check-up” or “I’ve been admitted for a thorough evaluation of my heart.”

Present Illness

This Present Illness is a complete, clear, and chronologic description of the problems promoting the patient’s visit, including the onset of the problem, the setting in which it developed, its manifestations, and any treatments to date.

  • Each principal symptoms should be well characterized, and should include the seven attributes of a symptom: 1) location; 2) quality; 3) quantity or severity; 4) timing, including onset, duration, and frequency; 5) the setting in which it occurs; 6) factors that have aggravated or relieved the symptom; 7) associated manifestations. It is also important to query the “pertinent positives” and “pertinent negatives” drawn from sections of the Review of Systems that are relevant to the Chief Complaint(s). The presence or absence of these additional symptoms helps you generate the differential diagnosis, which includes the most likely and, at times, the most serious diagnoses, even if less likely, which could explain the patient’s condition.
  • Other information is frequently relevant, such as risk factors for coronary artery disease in patients with chest pain, or current medications in patients with syncope.
  • The Present Illness should reveal the patient’s response to his or her symptoms and what effect the illness has had on the patient’s life. Always remember, the data flow spontaneously from the patient, but the task of oral and written organization is yours.
  • Patients often have more than one symptoms or concern. Each symptom merits its own paragraph and a full description.
  • Medications should be noted, including name, dose, route, and frequency of use. Also, list home remedies, nonprescription drugs, vitamins, mineral or herbal supplements, oral contraceptives, and medicines borrowed from family members or friends. Ask patients to bring in all their medications so that you can see exactly what they take.
  • Allergies, including specific reactions to each medication, such as rash or nausea, must be recorded, as well as allergies to foods, insects, or environmental factors.
  • Note tobacco use, including the type. Cigarettes are often reported in pack-years. If someone has quit, note for how long.
  • Alcohol and drug use should always be investigated and is often pertinent to the Present Illness.

Past History

  • Childhood illnesses: These include measles, rubella, mumps, whooping cough, chickenpox, rheumatic fever, scarlet fever, and polio. Also included are any chronic childhood illnesses.
  • Adult illnesses: Provide information relative to adult illnesses in each of the four areas: 1) medical: illnesses such as diabetes, hypertension, hepatitis, asthma, and human immunodeficiency virus; hospitalizations; number and gender of sexual partners; and risk-taking sexual practices; 2) surgical: dates, indications, and types of operations; 3) obstetric/gynecologic: obstetric history, menstrual history, methods of contraception, and sexual function; 4) psychiatric: illness and time frame, diagnoses, hospitalizations, and treatments.

Family History

Under family history, outline or diagram the age and health, or age and cause of death, of each immediate relative including parents, grandparents, siblings, children, and grandchildren. Review each of the following conditions and record whether they are present or absent in the family: hypertension, coronary artery disease, elevated cholesterol levels, stroke, diabetes, thyroid or renal disease, arthritis, tuberculosis, asthma or lung disease, headache, seizure disorder, mental illness, suicide, substance abuse, and allergies, as well as symptoms reported by the patient. Ask about any history of breast, ovarian, colon, or prostate cancer. Ask about any genetically transmitted diseases.

Personal and Social History

The personal and social history captures the patient’s personality and interests, sources of support, coping style, strengths, and concerns. It should include occupation and the last year of schooling; home situation and significant others; sources of stress, both recent and long-term; important life experiences such as military service, job history, financial situation, and retirement; leisure activities; religious affiliation and spiritual beliefs; and activities of daily living. Baseline level of function is particularly important in older or disabled patients. The personal and social history includes lifestyle habits that promote health or create risk, such as exercise and diet, including frequency of exercise, usual daily food intake, dietary supplements or restrictions, and use of coffee, tea, and other caffeinated beverages, and safety measures, including use of seat belts, bicycle helmets, sunblock, smoking detectors, and other devices related to specific hazards. Include sexual orientation and practices and any alternative health care practices. Avoid restricting the personal and social history to only tobacco, drug, and alcohol use. An expanded personal and social history personalizes your relationship with the patient and builds rapport.

Review of Systems

  • General: Usual weight, recent weight change, clothing that fits more tightly or loosely than before, weakness, fatigue, or fever.
  • Skin: Rashes, lumps, sores, itching, dryness, changes in color; change in hair or nails; changes in size or color of moles.
  • HEENT: 1) head: headache, head injury, dizziness, lightheadedness; 2) eyes: vision, glasses or contact lenses, last examination, pain, redness, excessive tearing, double or blurred vision, spots, specks, flashing lights, glaucoma, cataracts; 3) ears: hearing, tinnitus, vertigo, earaches, infection, discharge. If hearing is decreased, use or nonuse of hearing aids; 4) nose and sinuses: frequent colds, nasal stuffiness, discharge, or itching, hay fever, nosebleeds, sinus trouble; 5) throat: condition of teeth and gums, bleeding gums, dentures, if any, and how they fit, last dental examination, sore tongue, dry mouth, frequent sore throats, hoarseness.
  • Neck: “Swollen glands,” goiter, lumps, pain, or stiffness in the neck.
  • Breasts: Lumps, pain, or discomfort, nipple discharge, self-examination practices.
  • Respiratory: Cough, sputum (color, quantity; presence of blood or hemoptysis), shortness of breath (dyspnea), wheezing, pain with a deep breath (pleuritic pain), last chest x-ray. You may wish to include asthma, bronchitis, emphysema, pneumonia, and tuberculosis.
  • Cardiovascular: “Heart trouble”; high blood pressure; rheumatic fever; heart murmurs; chest pain or discomfort; palpitations; shortness of breath; need to use pillows at night to ease breathing (orthopnea); need to sit up at night to ease breathing (paroxysmal nocturnal dyspnea); swelling in the hands, ankles, or feet (edema); results of past electrocardiograms or other cardiovascular tests.
  • Gastrointestinal: Trouble swallowing, heartburn, appetite, nausea. Bowel movements, stool color and size, change in bowel habits, pain with defecation, rectal bleeding or black or tarry stools, hemorrhoids, constipation, diarrhea. Abdominal pain, food intolerance, excessive belching or passing of gas. Jaundice, liver, or gallbladder trouble; hepatitis.
  • Peripheral vascular: Intermittent leg pain with exertion (claudication); leg cramps; varicose veins; past clots in the veins; swelling in calves, legs, or feet; color change in fingertips or toes during cold weather; swelling with redness or tenderness.
  • Urinary: Frequency of urination, polyuria, nocturia, urgency, burning or pain during urination, blood in the urine (hematuria), urinary infections, kidney or flank pain, kidney stones, ureteral colic, suprapubic pain, incontinence; in males, reduced caliber or force of the urinary stream, hesitancy, dribbling.
  • Genital: Male: Hernias, discharge from or sores on the penis, testicular pain or masses, scrotal pain or swelling, history of sexually transmitted infections and their treatments. Sexual habits, interest, function, satisfaction, birth control methods, condom use, and problems. Concerns about HIV infection. Female: Age at menarche, regularity, frequency, and duration of periods, amount of bleeding; bleeding between periods or after intercourse, last menstrual period, dysmenorrhea, premenstrual tension. Age at menopause, menopausal symp- toms, postmenopausal bleeding. If the patient was born before 1971, exposure to diethylstilbestrol (DES) from maternal use during pregnancy (linked to cervical carcinoma). Vaginal discharge, itching, sores, lumps, sexually transmitted infec- tions and treatments. Number of pregnancies, number and type of deliveries, number of abortions (spontaneous and induced), complications of pregnancy, birth-control methods. Sexual preference, interest, function, satisfaction, any problems, including dyspareunia. Concerns about HIV infection.
  • Musculoskeletal: Muscle or joint pain, stiffness, arthritis, gout, backache. If present, describe location of affected joints or muscles, any swelling, redness, pain, tenderness, stiffness, weakness, or limitation of motion or activity; include timing of symptoms (e.g., morning or evening), duration, and any history of trauma. Neck or low back pain. Joint pain with systemic symptoms such as fever, chills, rash, anorexia, weight loss, or weakness.
  • Psychiatric: Nervousness, tension, mood, including depression, memory change, suicidal ideation, suicide plans or attempts. Past counseling, psycho- therapy, or psychiatric admissions.
  • Neurologic: Changes in mood, attention, or speech; changes in orientation, memory, insight, or judgment; headache, dizziness, vertigo, fainting, black- outs; weakness, paralysis, numbness or loss of sensation, tingling or “pins and needles,” tremors or other involuntary movements, seizures.
  • Hematologic: Anemia, easy bruising or bleeding, past transfusions, transfusion reactions.
  • Endocrine: “Thyroid trouble,” heat or cold intolerance, excessive sweating, excessive thirst or hunger, polyuria, change in glove or shoe size.

Supplement Documents

Principle Symptoms

  • Abdominal pain
  • Acid-base abnormalities
  • AIDS/HIV infection
  • Anemia
  • Back pain
  • Bleeding disorders
  • Chest pain
  • Cough, fever, and respiratory infections
  • Delirium and dementia
  • Diabetes
  • Diarrhea, acute
  • Dizziness
  • Dyspnea
  • Dysuria
  • Edema
  • Fatigue
  • GI bleeding
  • Headache
  • Hematuria
  • Hypercalcemia
  • Hypertension
  • Hyponatremia and hypernatremia
  • Hypotension
  • Jaundice and abnormal liver enzymes
  • Joint pain
  • Kidney injury, acute
  • Rash
  • Sore throat
  • Syncope
  • Weight loss, unintentional
  • Wheezing and stridor

Creatinine Clearance Estimation – Non-Steady State

March 8, 2017 Clinical Skills, Laboratory Medicine, Nephrology, Pharmacokinetics, Practice 2 comments , ,

Using non-steady-state serum creatinine values to estimate creatinine clearance is difficult, and a number of approaches have been proposed. The author use Equation 1 below to estimate creatinine clearance when steady-state conditions have not been achieved.

ClCr (mL/min) = { (Production of Creatinine in mg/day) – [(SCr 2 – SCr 1)(V Cr) / t]*(10 dL/L)} * [(1000 mL/L) / (1440 min/day)] / [(SCr 2)(10 dL/L)] [Equation 1]

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The daily production of creatinine in milligram is calculated by multiplying the daily production value in mg/kg/day from Table 5 by the patient’s weight in kg. The serum creatinine values in Equation 1 are expressed in units of mg/dL; t is the number (or fraction) of days between the first serum creatinine measurement (SCr1) and the second (SCr2). The volume of distribution of creatinine (Vcr) is calculated by multiplying the patient’s weight in kg times 0.65 L/kg. Equation 1 (or 79) is essentially a modification of the mass balance equation (we will discuss it in another thread later).

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where the daily production of creatinine in milligram has replaced the infusion rate of the drug and the second serum creatinine value replaced C ave. The second serum creatinine is used primarily because Equation 1 is most commonly applied when creatinine clearance is decreasing (serum creatinine rising), and using the higher of the two serum creatinine values results in a lower, more conservative estimate of renal function. Some have suggested that the iterative search process, as represented by the combination of Equation 28 and 37 (won’t be discussed here; if needed, please contact Tom for detail), be used:

Screen Shot 2017 03 08 at 9 29 36 PMwhere C2 represents SCr2, and C represents SCr1. (S)(F)(Dose/tau) represents the daily production of creatinine, and t represents the time interval between the first and second serum creatinine concentrations. Cl represents the creatinine clearance with the corresponding elimination rate constant K being Cl/V or the creatinine clearance divided by the creatinine volume of distribution. As discussed previously, the solution would require an iterative search, and the inherent errors in the calculation process probably do not warrant this type of calculation.

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Although Equation 1 (or Equation 79) can be used to estimate a patient’s creatinine clearance when a patient’s serum creatinine is rising or falling, there are potential problems associated with this and all other approaches using non-steady-state serum creatinine values. First, a rising  serum creatinine concentration may represent a continually declining renal function. To help compensate for the latter possibility, the second creatinine (SCr2) rather than the average is used in the denominator of Equation 1/79. Furthermore, there are non-renal routes of creatinine elimination that become significant in patients with significantly diminished renal function. Because as much as 30% of a patient’s daily creatinine excretion is the result of dietary intake, the ability to predict a patient’s daily creatinine production in the clinical setting is limited. One should also consider the potential errors in estimating creatinine production for the critical ill patient, the errors in serum creatinine measurements, and the uncertainty in the volume of distribution estimate for creatinine. Estimating creatinine clearance in a patient with a rising or falling serum creatinine should be viewed as a best guess under difficult conditions, and ongoing reassessment of the patient’s renal function is warranted.

[Clinical Art][Pharmacokinetics] Interpretation of Plasma Drug Concentrations (Steady-State)

November 11, 2016 Clinical Skills, Critical Care, Pharmacokinetics, Practice No comments , , , , , , , , , , , ,

Plasma drug concentration are measured in the clinical setting to determine whether a potentially therapeutic or toxic concentration has been produced by a given dosage regimen. This process is based on the assumption that plasma drug concentrations reflect drug concentrations at the receptor and, therefore, can be correlated with pharmacologic response. This assumption is not always valid. When plasma samples are obtained at inappropriate times or when other factors (such as delayed absorption or altered plasma binding) confound the usual pharmacokinetic behavior of a drug, the interpretation of serum drug concentrations can lead to erroneous pharmacokinetic and pharmacodynamic conclusions and utimately inappropriate patient care decisions. These facors are discussed below.

Confounding Factors

To properly interpret a plasma concentration, it is essential to know when a plasma sample was obtained in relation to the last dose administered and when the drug regimen was initiated.

  • If a plasma sample is obtained before distribution of the drug into tissue is complete, the plasma concentration will be higher than predicted on the basis of dose and response. (avoidance of distribution)
  • Peak plasma levels are helpful in evaluating the dose of antibiotics used to treat severe, life-threatening infections. Although serum concentrations for many drugs peak 1 to 2 hours after an oral dose is administered, factors such as slow or delayed absorption can significantly delay the time at which peak serum concentrations are attained. Large errors in the estimation of Css max can occur if the plasma sample is obtained at the wrong time. Therefore, with few exceptions, plasma samples should be drawn as trough or just before the next dose (Css min) when determining routine drug concentration in plasma. These trough levels are less likely to be influenced by absorption and distribution problems. (slow or delayed absorption)
  • When the full therapeutic response of a given drug dosage regimen is to be assessed, plasma samples should not be obtained until steady-state concentrations of the drug have been achieved. If drug doses are increased or decreased on the basis of drug concentrations that have been measured while the drug is still accumulating, disastrous consequences can occur. Nevertheless, in some clinical situations it is appropriate to measure drug levels before steady state has been achieved. If possible, plasma samples should be drawn after a minimum of two half-lives beause clearance values calculated from drug levels obtained less than one half-life after a regimen has been initiated are very sensitive to small differences in the volume of distribution and minor assay errors. (Whether steady-state attained)
  • The impact of drug plasma protein binding on the interpretation of plasma drug coencentration has been discussed in thread "The Plasma Protein Concentration and The Interpretation of TDM Report" before.

Revising Pharmacokinetic Parameters

The process of using a patient's plasma drug concentration and dosing history to determine patient-specific pharmacokinetic parameters can be complex and difficult. A single plasma sample obtained at the appropriate time can yield information to revise only one parameter, either the volume of distribution or clearance, but not both. Drug concentrations measured from poorly timed samples may prove to be useless in estimating a patient's V or Cl values. Thus, the goal is to obtain plasma samples at times that are likely to yield data that can be used with confidence to estimate pharmacokinetic parameters. In addition, it is important to evaluate available plasma concentration data to determine whether they can be used to estiamte, with some degree of confidence, V and/or Cl. The goal in pharmacokinetic revisions is not only to recognize which pharmacokinetic parameter can be revised, but also the accuracy or confidence one has in the revised or patient-specific pharmacokinetic parameter. In the clinical setting, based on the way drugs are dosed and the recommended time to sample, bioavailability is almost never revised, volume of distribution is sometimes revised, and most often clearance is the pharmacokientic parameter that can be revised to determine a patient-specific value.

Volume of Distribution

A plasma concentration that has been obtained soon after administration of an initial bolus is primarily determined by the dose administered and the volume of distribution. This assumes that both the absorption and distribution phases have been avoided.

C1 = (S) (F) (Loading Dose) x e(-kt1) / V (IV Bolus Model)

When e(-kt1) approches 1 (i.e., when t1 is much less than t1/2), the plasma concentration (C1) is primarily a function of the administered dose and the apparent volume of distribution. At this point, very little drug has been eliminated from the body. As a clinical guideline, a patient's volume of distribution can usually be estimated if the absorption and distribution phase are avoided and t1, or the interval between the administration and sampling time, is less than or equal to one-third of the drug's half-life. As t1 exceeds one-third of a half-life, the measured concentration is increasingly infuenced by clearance. As more of the drug is eliminated (i.e., t1 increases), it is difficult to estimate the patient's V with any certainty. The specific application of this clinical guideline depends on the confidence with which one knows clearance. If clearance is extremely variable and uncertain, a time interval of less than one-third of a half-life would be necessary in order to revise volume of distribution. On the other hand, if a patient-specific value for clearance has already been determined, then t1 could exceed one-third of a half-life and a reasonably accurate estimate of volume of distribution could be obtained. It is important to recognize that the pharmacokinetic parameter that most influences the drug concentration is not determined by the model chosen to represent the drug level. For example, even if the dose is modeled as a short infusion, the volume of distribution can still be the important parameter controlling the plasma concentration. V is not clearly defined in the equation (see it below); nevertheless, it is incorporated into the elimination rate constant (K).

C2 =[(S) (F) (Dose/tin) / Cl]*(1-e-ktin)(e-kt2)

Although one would not usually select this equation to demonstrate that the drug concentration is primarily a function of volume of distribution, it is important to recognize that the relationship between the observed drug concentration and volume is not altered as long as the total elapsed time (tin + t2) does not exceed one-third of a half-life.

Our assumption in evaluating the volume of distribution is that although we have not sampled beyond one-third of a t1/2, we have waited until the drug absorption and distribution process is complete.

Clearance

A plasma drug concentration that has been obtained at steady state from a patient who is receiving a constant drug infusion is determined by clearance.

Css ave = (S) (F) (Dose / tau) / Cl

So, the average steady-state plasma concentration is not influenced by volume of distribution. Therefore, plasma concentrations that represent the average steady-state level can be used to estimate a patient's clearnace value, but they cannot be used to estimate a patient's volume of distribution. Generally, all steady-state plasma concentrations within a dosing interval that is short relative to a drug's half-life (tau =<1/3 t1/2) approximate the average concentration. Therefore, these concentrations are also primarily a function of clearance and only minimally influenced by V.

Also the below equation could be used,

Css 1 =[(S)(F)(Dose)/V]/(1-e-kτ)*(e-kt1)

the expected volume of distribution should be retained and the elimination rate constant adjusted such that Css1 at t1 equals the observed drug plasma concentration.

Sensitivity Analysis

Whether a measured drug concentration is a function of clearance or volume of distribution is not always apparent. When this is difficult to ascertain, one can examine the sensitivity or responsiveness of the predicted plasma concentration to a parameter by changing one parameter while holding the other constant. For example, for maintenance infusion, a plasma concentration (C1) at some time intervnal (t1) after a maintenance infusion has been started should be:

C1=[(S)(F)(Dose/τ)/Cl]*(1-e-kt1)

when the fraction of steady that has been reached (1-e-kt1) is small, large changes in clerance are frequently required to adjust a predicted plasma concentration to the appropriate value. If a large percentage change in the clearance value results in a disproportionately small change in the predicted drug level, then something other than clearance is controlling (responsible for) the drug concentration. In this case, the volume of distribution and the amount of drug administered are the primary determinants of the observed concentration. Also in cases where the drug concentration is very low, it might be assay error or sensitivity that is the predominant factor in determining the drug concentration making the ability to revise for any pharmacokinetic parameter limited if not impossible.

This type of sensitivity analysis is useful to reinforce the concept that the most reliable revisions in pharmacokinetic parameters are made when the predicted drug concentration changes by approximately the same percentage as the pharmacokinetic parameter undergoing revision.

When a predicted drug concentration changes in direct proportion, or inverse proportion to an alteration in only one of the pharmacokinetic parameters, it is likely that a measured drug concentration can be used to estimate that patient-specific parameter. But when both clearance and volume of distribution have a significant influence on th prediction of a measured drug concentration, revision of a patient's pharmacokinetic parameters will be less certain because there is an infinite number of combinations for clearance and volume of distribution values that could be used to predict the observed drug concentration. When this occurs, the patient's specific pharmacokinetic characteristics can be estimated by adjusting one or both of the pharmacokinetic parameters. Nevertheless, in most cases additional plasma level sampling will be needed to accurately predict the patient's clearance or volume of distribution so that subsequent dosing regimens can be adjusted.

When the dosing interval is much shorter than the drug's half-life, the changes in concentration within a dosing interval are relatively small, and any drug concentration obtained within a dosing interval can be used as an approximation of the average steady-state concentration. Even though Css max and Css min exist,

Css max =[(S)(F)(Dose)/V]/(1-e-kτ)

and

Css min =[(S)(F)(Dose)/V]/(1-e-kτ)*(e-kτ)

and could be used to predict peak and trough concentrations, a reasonable approximation could also be achieved by using the Css ave, that is

Css ave =(S)(F)(Dose/τ)/Cl

This suggests that even though Css max and Css min do not contain the parameter clearance per se, the elimination rate constant functions in such a way that the clearance derived from Css max or Css min and Css ave would all essentially be the same.

In the situation in which the dosing interval is greater than one-third of a half-life, the use of Css max and Css min are appropriate as not all drug concentrations within the dosing interval can be considered as the Css ave. However, as long as the dosing interval has not been extended beyond one half-life, clearance is still the primary pharmacokinetic parameter that is responsible for the drug concentrations within the dosing interval. Although the elimination rate constant and volume of distribution might be manipulated in Css max and Css min, it is only the product of those two numbers (i.e., clearance) that can be known with any certainty: Cl = (K) (V).

If a drug is administered at a dosing interval that is much longer than the apparent half-life, peak concentrations may be primarily a function of volume of distribution. Since most of the dose is eliminated within a dosing interval, each dose can be thought as something approaching a new loading dose. Of course for steady-state conditions, at some point within the dosing interval, the plasma concentration (Css ave) will be determined by clearance. Trough plasma concentrations in this situation are a function of both clearance and volume of distribution. Since clearance and volume of distribution are critical to the prediction of peak and trough concentrations when the dosing interval is much longer than the drug t1/2, a minimum of two plasma concentrations is needed to accurately establish patient-specific pharmacokinetic parameters and a dosing regimen that will achieve desired peak and trough concentrations.


Choosing A Model to Revise or Estimate A Patient's Clearance at Steady State

As previously discussed, a drug's half-life often determines the pharmacokinetic equation that should be used to make a revised or patient-specific estimate of a pharmacokinetic parameter. A common problem encountered clinically, however, is that the half-life observed in the patient often differs from the expected value. Since a change in either clearance or volume of distribution or both may account for this unexpected value, the pharmacokinetic model is often unclear. One way to approach this dilemma is to first calculate the expected change in plasma drug concentration assocaited with each dose:

delta C = (S) (F) (Dose) / V

where delta C is the change in concentration following the administration of each dose into the patient's volume of distribution. This change in concentration can then be compared to the steady-state trough concentration measured in the patient.

(S) (F) (Dose) / V versus Css min

or

delta C versus Css min

When the dosing interval (tau) is much less than the drug half-life, delta C will be small when compared to Css min. As the dosing interval increases relative to tau, delta C will increase relative to Css min. Therefore, a comparison of delta C or (S) (F) (Dose) / V to Css min can serve as a guide to estimating the drug t1/2 and the most appropriate pharmacokineitc model or technique to use for revision. With few exceptions, drugs that have plasma level monitoring are most often dosed at intervals less than or equal to their half-lives. Therefore, clearance is the pharmacokinetic parameter most often revised or calculated for the patient in question. The following guidelines can be used to select the pharmacokinetic model that is the least complex and therefore the most appropriate to estimate a patient-specific pharmacokientic parameter.

Condition 1

When, (S) (F) (Dose) / V =< 1/4 Css min

Then, tau =<1/3 t1/2

Under these conditions, Css min ≈ Css ave

And Cl can be estimated by Cl = (S) (F) (Dose / tau) / Css ave

Rules/Conditions: Must be at steady state.

Condition 2

When, (S) (F) (Dose) / V =< Css min

Then, tau =< t1/2

Under these conditions, Css min + (1/2) (S) (F) (Dose) / V ≈ Css ave

And Cl can be estimated by Cl = (S) (F) (Dose / tau) / Css ave

Rules/Conditions: Must be at steady state; C is Css min; Bolus model for absorption is acceptable (dosage form is not sustained release; short infusion model is not required, that is, tin =<1/6t1/2)

Conditon 3

When, (S) (F) (Dose) / V > Css min

Then, tau > t1/2

Under these conditions: Css min + (S) (F) (Dose) / V = Css max

where V is an assumed value from the literature.

K is revised (Krevised):

Krevised = ln {[(Css min + (S) (F) (Dose / V)] / Css min} / tau = ln (Css max / Css min) / tau

Rules/Conditions: Must be at steady state; C is Css min; Bolus model for absorption is acceptable (dosage form is not sustained release; short infusion model is not required, that is, tin =< 1/6 t1/2)

Note that the approaches used become more complex as the dosing interval increases relative to the drug half-life. If a drug is administered at a dosing interval less than or equal to one-third of its half-life and the technique in Condition 3 is used to revise clearance, the revised clearance would be correct. The calculation is not wrong, just unnecessarily complex. However, if a drug is administered at a dosing interval that exceeds one half-life and the technique in Condition 1 is used to revise clearance, the revised clearance value would be inaccurate because Css min cannot be assumed to be approximately equal to Css ave. While it could be argued that the technique used in Condition 3 would suffice for all the previous conditions, it is more cumbersome and tends to focus on the intermediate parameters, K and V rather than Cl. One should also be ware that as the dosing interval increases, relative to the drug's half-life, the confidence in a revised clearance diminishes because the volume of distribution, which is an assumed value from the literature, begins to influence the revised clearance to a greater degree. As a general rule, the confidence in Cl is usually good when the dosing interval is < t1/2, steady state has been achieved, and drug concentrations are obtained properly.

[Clinical Skills] Therapeutics Planning

April 12, 2016 Clinical Skills, Pharmacotherapy, Practice, Therapeutics No comments , , , , , , , , , , , , , , ,

Also see Pharmacy Profession Forum for the thread "[Diagnosis] Diagnostic Series" at http://forum.tomhsiung.com/pharmacy-students-and-residents/clinical-skills/817-diagnosis-diagnostic-series.html

Identify the Problems

Step 1 Obtain Patient Data

Consider all available patient data. Review all previously charted data (history, physical examination findings, results of laboratory and diagnostic tests) and interview the patient for the patient's medication history. Reviewall relevant data resources, including data from the current patient chart, data from past charts, data obtained from patient interviews or interviews with relatives or significant others if the patient is not capable of providing information, and uncharted data available from team members. Seeking out and then identifying relevant data requires patience and methodical scrutiny. Note that the patient's story may vary depending on who interviewed the patient and when the patient was interviewed. Some data may be contradictory. But it is important to gather and then consider all available data.

Patient factors that by themselves appear unimportant may be important when considered in the context of other patient data. Pertinent positive data (abnormal findings) include abnormal laboratory results such as a serum potassium level that exceeds the upper limit of the reference range, abnormal signs and symptoms described by the patient, and abnormalities noted on physical examination, and are easy to identify. Pertinent negative data (findings that are normal but, given the patient's disease or condition, would have been expected to be abnormal) are more difficult to recognize, and identifying them requires a good understanding of human disease and pharmacotherapeutics.

Create a working list of the data. Subdivide the data into lists of subjective data and objective data. Subjective data, such as coughing, pain, and itching, are describable but cannot be precisely measured or quantified. Some clinicians view all data obtained directly from the patient to be subjective data, because the data are not verifiable by an independent observer and must be considered just a story. Objective data, such as blood pressure, heart rate, and temperature, are data that can be precisely measured or quantified. By convention, data that are obtained by the health care professional by direct observation of the patient or are obtained during the physical examination but that cannot be precisely quantified are considered objective data because the data were obtained by an objective, trained clinician. Data documented by other health care professionals are considered objective data.

Step 2 Group Related Data

Evaluate the list of objective and subjective data for possible relationships among the data. This step requires comprehensive knowledge of the signs and symptoms of disease and pharmacotherapy and becomes easier with experience. For example, subjective complaints of fever, one episode of chills, and productive cough combined with objective data of leukocytosis with an increased percentage of bands, a chest radiograph showing right middle lobe consolidation, and sputum positive for gram-positive encapsulated cocci in pairs are related. A less experienced clinician should be able to recognize that the patient has some kind of lower respiratory tract bacterial infection.

Work through the list of patient data making sure that every piece of patient data is considered. Note that it only takes one piece of data to identify a patient problem. For example, a patient may smoke tobacco but have normal physical examination findings and normal laboratory results. The patient's self-identification of the smoking history is enough to categorize the patient as a smoker (the problem). Some data may belong with more than one group of data. For example, a blood pressure of 160/110 mm Hg belongs with data related to the patient's diagnosis of hypertension, but if the patient had been prescribed antihypertensive drug therapy but missed many doses, the blood pressure of 160/110 mm Hg also belongs with data related to patient nonadherence.

Step 3 Determine Each Problem

Evaluate each group of related subjective and objective data items to determine the specific patient problem or issue. The problem is not always a specific diagnosis but may be a preliminary identification of the issue pending acquistition of additional data (e.g., acute diarrhea, not shigellosis). The problem list is refined as more data become available. Patient problems include current medical problems such as hypertension, pneumonia, asthma, diabetes, and gastrointestinal bleeding; past medical problems such as history of migraine headache, hip fracture, deep vein thrombosis, and myocardial infarction; past surgeries such as appendectomy, tonsillectomy, coronary artery bypass grafts, and transurethral resection of the prostate; and issue such as nonadherence, obesity, illicit drug abuse, alcohol use, tobacco use, and allergies.

Step 4 Assess Each Problem

  • Each problem is then assessed in terms of each of the following characteristics:
  • Acuity (acute or chronic)
  • Severity (mild, moderate, or severe)
  • Symptom level (symptomatic or asymptomatic)
  • Treatment status (treated or untreated)
  • Degree of control (controlled or uncontrolled)
  • Classification (staging of disease)

Knowing these characteristics is useful when prioritizing patient problems and when planning patient-specific drug and nondrug interventions. Management of a patient's acute, severe, uncontrolled, untreated asthma exacerbation will take precedence over treatment of any of the patient's other chronic and controlled problems. Because historical problems cannot be assessed for these characteristics, by convention these problems are simply documented as "S/P" (meaning "status post" or "a history of").


Prioritize The Problems

Prioritization means ranking the patient problems with the most urgent problems at the top of the list and the least urgent problems at the bottom of the list. Prioritization is a way of ordering the relative need for intervention and is not meant to imply a rank ordering of importance or significance to the patient's overall health care needs. Problems of equal urgency are still listed in a rank order although the plans document the need to address each problem simultaneously. Historical (inactive) problems are not ranked but are simply listed at the bottom of the problem list. Problem lists are dynamic lists that evolve and are modified as new data become available.

Step 1 Identify the Active Problems

Active problems are problems that require some kind of drug or nondrug intervention to resolve and/or manage the problem.

Step 2 Identify the Inactive Problems

Inactive problems are problems that do not require any kind of drug or nondrug intervention and are of historical interest only. Examples of inactive problems include a history of an appendectomy at age 12, a history of pneumonia 2 years ago, a history of smoking two packs of cigarettes per day until quitting 10 years ago, etc. Although inactive problems do not require planning for current drug or nondrug therapy interventions, inactive problems are still identified and listed on the patient problem list so that they can be considered when planning drug and nondrug interventions for active problems. For example, a patient with a history of splenectomy is at increased risk of infection with some pathogens. Knowledge of this risk will help in planning patient-specific antibiotic therapy in the event that the patient has signs and symptoms consistent with infection.

Step 3 Rank the Problems

Rank-order the active patient problems. One approach to ranking patient problems is to identify the problem that needs the most immediate attention and then rank the remaining active problems in order of need for intervention. The number one problem is the problem that if left untreated will cause the most harm to the patient in the shortest amount of time. Another approach is to work from the bottom of the list up by determining the problem requiring the lest attention. This problem is ranked as the least important problem. The pharmacist repeats the ranking process with the remaining problems until all are ranked. Regardless of the approach, the active problems are placed at the top of the list, inactive problems are at the botton of the list, and active but less acute problems are in the middle. As noted previously, the rank ordering is rather arbitrary if the the problems all have relatively equal need for intervention.

Clinicians given the same list of patient data may develop different prioritized lists. This is not unexpected; no one list is correct. Lists are developed based on the clinical judgment and experience of the practitioner. In addition, because the focus of the pharmacist is on therapeutic issues rather than on differential diagnosis, the pharmacist-generated patient problem list may be similar although not necessarily identical to the problem list generated by physicians, nurses, or other health care professionals.


Select Patient-Specific Drug and Nondrug Interventions

Once the prioritized patient problem list is developed, the next step is to select patient-specific drug and nondrug interventions for each and nondrug interventions.

Determine appropriate nondrug interventions, including patient eduation. For example, an important part of the management of allergic rhinitis is avoidance of allergens; patients may benefit from education regarding allergen avoidance.

Determine an appropriate medication regimen for each patient problem that can be treated and/or managed with medications. For each medication selected, include the dosage, the dosage formulation, the route of administration, dosing interval, duration of therapy, and rationale (the evidence-based reason for selecting the patient-specific therapeutic intervention). The general approach is to develop the therapeutic plan for each problem and then integrate the individual plans, with care taken to ensure that each component of the plan is appropriate given the other plans and that the overall integrated plan is achievable for the pateint. For example, when considered individually plans for therapeutic interventions for a patient with multiple chronic medical conditions may seem reasonable and appropriate, but when considered together they may not be doable if the multiple medication regimens require the patient to adhere to multiple sets of complicated instructions (e.g., take with food, take 2 hours before eating, take every 4 hours around the clock, take every 8 hours around the clock, do not take within 2 hours of taking another medication, etc.).

Selection of a specific regimen requires assessment of each patient problem in the context of everything that is known about the patient such as other patient problems and medications, social habits, cultural beliefs, and willingness to commit to a course of therapy, as well as external factors such as insurance coverage and access to refrigeration for storage of refrigerated medications. See below,

Patient-specific factors

  • What regimens have effectively managed the problem in the past?
  • What regimens have not effectively managed the problem in the past?
  • How might other patient problems influence the proposed regimen?
  • How might the proposed regimen influence other patient problem?
  • Does the patient have any culturally based needs?

External factors

  • State-of-the-art therapeutics (e.g., current guidelines)
  • Cost of the proposed therapy
  • Formulary limitations

For example, a patient who has responded well to a specific decongestant in the past will most likely respond well to the same decongestant in the future. A patient with renal insufficiency is at risk of developing seizures from the accumulation of normeperidine, a renally eliminated metabolite of meperidine. A drug with negative inotropic effects may worsen a patient's congestive heart failure.

Step 1 Determine Short-Term and Long-Term Goals of Therapy

All drug and nondrug interventions should be in the context of the specific short-term and long-term goals of therapy, which may or may not be the same depending on the specific patient problem. For example, the short-term goal for patient being treated for a hypertensive emergency is to reduce the diastolic blood pressure to 100 to 105 mm Hg within 2 to 6 hours of presentation with a maximum reduction of 25% or less of the initial diastolic blood pressure. The long-term goal is to reduce the diastolic blood pressure to 85 to 90 mm Hg over the next 2 to 3 months to reduce the long-term morbidity and mortality associated with the elevated diastolic blood pressure.

Determine specific goals and outcomes of therapy before doing any other planning. Set specific goals for each patient problem and for the overall therapeutic outcome in general. When setting therapeutic goals, consider long-term factors such as the impact of the therapeutic regimen on the patient's quality of life and survival. For example, a long-term weight reduction plan is not appropriate for a patient with a short life expectancy. Select target therapeutic ranges for all objective parameters (e.g., systolic blood pressure between 110 and 130 mm Hg; serum potassium level between 3.5 and 4.5 mEq/L, etc.)

Consider the severity of disease and the short-term or long-term nature of therapy when setting therapeutic goals. For example, consider the differences in the goals of insulin therapy for a young patient with newly diagnosed type 1 diabetes mellitus and significant cardiovascular and peripheral vascular disease. Evidence suggests that tight control of blood glucose levels may delay the onset and decrease the severity of the complications of diabetes. Therefore the target blood glucose level for the young patient with newly diagnosed daibetes is lower and has a narrower acceptable range than that for the elderly patient with diabetes and longstanding disease who has already developed complications from the disease and is at risk of hypoglycemia-related falls.

Step 2 Create A List of Options

Identify all classes of drugs and possible therapeutic approaches for each problem; do not eliminate any option at this stage of planning. The options list is usually a mental list, although students and inexperienced clinicians may find it helpful to create and then work from a written list. Depending on how familiar the pharmacist is with the management of the medical condition, this step may require review of current pharmacotherapeutics and human disease textbooks, literature searches of the current pharmacy and medical literature, review of current treatment guidelines, or consultation with colleagues. This step becomes easier and more time efficient with practice and experience. As the member of the heath care team with the most knowledge of pharmacotherapy, it is the pharmacist's responsibility to identify all possible drug therapy options.

Step 3 Eliminate Options Based on Patient-Specific and External Factors

Once all therapeutic options are identified, eliminate options based on the comparative effectiveness of the drugs; the suitability of the drug for the patient given the other patient medical conditions and drug therapies; the ability of the patient to adhere to the proposed regimen; and other factors such as the effectiveness of previous treatment regiments, cost, and formulary restrictions. Consider the impact of the therapeutic option on other patient problems and the influence of other patient problems on the therapeutic option.

Drug-specific factors

  • Effectiveness of the clinical outcome (e.g., evidence-based benefit)
  • Pharmacologic mechanisms
  • Effectiveness of the drugs (e.g., physiologic effect, potency, maximum effect, slope of effect-concentration curve)
  • Evidence-based toxicity of the drug
  • Toxicity of the drugs (e.g., therapeutic index/window)
  • Drug delivery systems (e.g., inhalant, sublingual, oral)
  • How drug get active in the body (e.g., prodrug)
  • In-body drug process/pharmacokinetics (e.g., absorption, distribution, metabolism, excretion)
  • Drug interactions

Patient-specific factors

  • What regimens have effectively managed the problem in the past?
  • What regimens have not effectively managed the problem in the past?
  • How might other patient problems influence the proposed regimen? (e.g., renal failure, hepatic failure, genetic variability/mutation, etc.)
  • How might the proposed regimen influence other patient problem?
  • Does the patient have any culturally based needs?
  • The severity of the problem
  • How the patient's life style affect the proposed regimen?
  • The past patient experiences
  • The patient's ability to adhere to the proposed regimen

External factors

  • State-of-the-art therapeutics (e.g., current guidelines)
  • Cost of the proposed therapy
  • Formulary limitations
  • Risk of medication errors

Step 4 Select Appropriate Drug and Nondrug Interventions

Decisions about appropriate drug and nondrug interventions are based on past patient experiences, assessment of the severity of the problem, drug-specific factors such as the therapeutic index of the drug, and specific patient factors such as the presence of chronic renal or hepatic disease that may influence the elimination or metabolism of the drug. Determine the best drug and nondrug regimen, including each specific drug to be used, dosage, route, duration of therapy, and rationle for the selection of each drug and nondrug component of the regimen. For example, if a patient failed to stop smoking because the patient developed varenicline-associated side effects and stopped taking the medication, then the patient should not be prescribed varenicline the next time the patient attempts to quite smoking. If a patient's prescription medication insurance no longer covers a specific branded product, then every effort should be made to find an equivalent medication, generic or otherwise, that is paid for by the prescription medication insurance plan.

The rationale, the reason why the specific intervention was selected, should be patient specific and based on current published evidence. The rationale should be documented in the SOAP note in the patient chart even if verbally discussed with the prescriber. For example, the recommendation to initiate antihypertensive drug therapy with hydrochlorothiazide 12.5 mg daily for a patient with newly diagnosed uncomplicated hypertension is based on the recommendations of the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. The recommendation to vaccinate or note vaccinate a person with the influenza vaccine is based on current Centers for Disease Control and Prevention recommendations.

Step 5 Identify Alternative Interventions

An important part of the planning process is anticipation of potential patient problems with the prescribed and/or recommended drug and nondrug interventions ("what if"). A well-though-out plan includes alternative medication regimens for common potential problems, such as the development of an allergy or adverse reaction to the initial therapeutic regimen, lack of desired therapeutic response to the initial therapeutic regimen, and identification of additional patient problems that may influence the effectiveness or pharmacokinetic profile of the initial therapeutic regimen. Anticipation of these potential issues allows the creation of well-thought-out alternative therapeutic plans instead of therapeutic plans hastily chosen when unanticipated patient problems suddenly appear. For example, therapeutic planning for a patient with newly diagnosed hypertension should include plans for what to do if the initial treatment fails to lower the blood pressure or has to be discontinued because of the development of intolerable side effects (both very common issues).

(The End)

[Clinical Skills] Taking Medication History

April 6, 2016 Clinical Skills, Practice No comments , , ,

1.Ask open-ended questions at the start of the interview and then move to more direct and targeted questions as the interview proceeds.

e.g., to ask the patient to describe any medications taken daily;
e.g., to ask the patient to describe the size, shape, and color of the medication regularly taken (a more direct and targeted question).

2.Avoid asking leading questions, multiple questions, and excessive yes/no questions.

e.g., a leading question such as "Does your tuberculosis medication turn your urine red?" may make the patient think the medication is supposed to turn the urine red and that something is wrong with the patient if his or her urine is not red.

3.Probe for medication-related effects by asking more general questions.

e.g., "How are you tolerating your tuberculosis medications?", "Have you noticed anything different or unusual since you started taking the medication?"

4.Avoid the trap of asking a series of rapid-fire questions without giving the patient time to answer. Give the patient ample time to address each question before asking another question.

5.Getting into a pattern of asking a series of yes/no questions also is very easy, especially toward the end of the interview, when the pharmacist asks specific and targeted questions.

This type of rapid-fire yes/no questions creates one-sided conversations and may diminish the flow of information from patients.

e.g., "Do you take anything for headache?", "Do you take anything for your eyes?", "Do you take anything for your heart?", "Do you take anything for your breathing?", "Do you take anything when you have a cold?", "Have you ever taken penicillin?"

6.Encourage patients to talk about their experience with medications.

Demographic Information

  • Age/date of birth
  • Height and weight
  • Race and/or ethnic origin
  • Type of residence
  • Education
  • Occupation
  • Lifestyle

Housing situation (e.g., loarding hourse, private home, apartment, shelter, living on the street)

The people living with the patient (e.g., spouse, young children, elderly relatives, extended family)

The patient's type of work and work schedule (i.e., day shift, night shift, rotating shift schedule, part time, full time)

Dietary Information

  • Dietary restrictions
  • Dietary supplements
  • Dietary stimulants
  • Dietary suppressants

Social Habits

  • Tobacco use

Packs per day/ppd

pack-years/pk-yr (e.g., 2 ppd for 5 years; 10 pk-yr)

  • Alcohol use (Men, women, respectively)

Lifetime abstainer

Former infrequent drinker

Current drinker

Infrequent drinker

Light drinker

Moderate drinker

Heavier drinker

Binge drinker

  • Illicit drug use

Document the duration of use, amount of each agent consumed, frequency of use, and reasons for use of each agent without being judgemental.

Determine the type, quantity, pattern, and duration of alcohol use.

Screen Shot 2016-04-06 at 6.46.32 PMTo assess tobacco use, note at what age the patient first started smoking tobacco and when the patient quit smoking (if applicable). One pack-year is equivalent to smoking one pack of cigarettes daily for 1 year. A 10 pk-yr tobacco history is quivalent to smoking 0.5 ppd for 20 years, 1 ppd for 10 years, or 2 ppd for 5 years.

Illicit drug use may be difficult to ascertain. Obtain this information in a professional, nothreatening, nonjudgmental manner. Do not try to guess which patients are more or less likely to use these agents but probe for this information with every patient. 


Current Prescription Medications

  • Name (proprietary and nonproprietary) and/or description

Dosage form (e.g., tablet, capsule, liquid, topical formulation)

Size, shape, and color of the dosage form

Any words, letters, and numbers on the dosage form that the patient can remember or that can be seen on the dosage form

  • Dose (prescribed and actual, and reason for discrepancy)
  • Dose schedule (routine times patient taking each dose, prescribed and actual, and reason for discrepancy)
  • Reason for taking the medication (including clarification any discrepancies regarding customary uses of medications with the prescriber)
  • Start date (exact date, duration of therapy)
  • Outcome of therapy

Medication Names

Patients may not be able to remember the names of all their medications. If this is the case, obtain a detail description of each medication, including the dosage form (e.g., tablet, capsule, liquid, topical formulation); size, shape, and color of the dosage form; and any words, letters, and numbers on the dosage form that the patient can remember or that can be seen on the dosage form. If the patient cannot remember the dosage of the drug, the pharmacist may be able to identify the drug and/or dosage from other details the patient provides. However, clearly document the patient's description and note that the medication might be a specific product.

Many physicians, nurses, and other health care profesionals typically know the proprietary (trade) name of the medication but are less familiar with the nonproprietary (generic) medication names. Therefore when a patient identifies a medication by the proprietary name, document both the proprietary and nonproprietary names. If the patient identifies a medication by the nonproprietary name, document the nonproprietary name. For combination medications, document the nonproprietary names of all active ingredients in the bombination  product.

Dose Schedule

Obtain the prescribed dosing schedule (e.g., four times a day, two times a day, once a day) and note the routine times the pateint takes each dose. If a discrepancy between the prescribed dosing schedule and the schedule the patient uses is apparent (e.g., the patient is supposed to take the medication four times a day but takes it two times a day), note the discrepancy and try to determine the reason the patient uses the drug differently from the way it is prescribed.

Reason for Taking the Medication and Start Date

Determine when the patient started taking the prescription medication and the reason the pateint gives for taking the medication. Exact dates are important in determining whether an adverse or allergic reaction is a result of a specific medication and whether the prescribed medication is effectively treating or controlling a specific condition. For example, a patient with elevated blood pressure may claim to adhere to his or her blood pressure medication regimen yet still have elevated blood pressure. The decision to continue or discontinue the medication depends on when the patient started the current regimen. The regimen would continue unchanged if the patient has just started the medication the previous week but would need to be changed if the patient had been taking the medication for 2 months. Some pateints may not known the specific reason they are taking their medications because they forgot or misunderstand the reason it has been prescribed. Document the reasons the patient gives for taking the medication and clarify any discrepancies regarding customary uses of medications with the prescriber, not the patient.

No Demand (prn) Medications

For as needed (prn, on demand) prescription and nonpresctiption medications, document the possible use as well as the patient's actual use of the medication. Quantification is important; do not accept imprecise descriptive terms. Patients may or may not be able to describe their frequency of use but may be able to describe how often they get the prescription refilled or buy a new supply of nonprescription medication; both given an indirect indication of frequency of use. One approach to quantifying the amount of medication actually consumed by the patient is to inquire how often the patient has to obtain a new supply of the medication.

Past Prescription Medications

  • Name (proprietary and nonproprietary) and/or description

Dosage form (e.g., tablet, capsule, liquid, topical formulation)

Size, shape, and color of the dosage form

Any words, letters, and numbers on the dosage form that the patient can remember or that can be seen on the dosage form

  • Dose (prescribed and actual, and reason for discrepancy)
  • Dose schedule (routine times patient taking each dose, prescribed and actual, and reason for discrepancy)
  • Reason for taking the medication (including clarification any discrepancies regarding customary uses of medications with the prescriber)
  • Start date (exact date, duration of therapy)
  • Stop date (exact date, duration of therapy)
  • Reason for stopping
  • Outcome of therapy

Knowledge of past prescriptions helps the pharmacist understand the medications used, either successfully or unsuccessfully, to treat current and past medical problems; this knowledge guides recommendations regarding new medication regimens. Patients are unlikely to remember all these details for past medications. Document the details the patient can remember; avoid excessive "grilling" of the patient.

Current Nonprescription Medications

  • Name (proprietary and nonproprietary) and/or description

Dosage form (e.g., tablet, capsule, liquid, topical formulation)

Size, shape, and color of the dosage form

Any words, letters, and numbers on the dosage form that the patient can remember or that can be seen on the dosage form

  • Dose (recommended/prescribed and actual, and reason for discrepancy)
  • Dose schedule (routine times patient taking each dose, recommended/prescribed and actual, and reason for discrepancy)
  • Reason for taking the medication (including clarification any discrepancies regarding customary uses of medications with the prescriber)
  • Start date (exact date, duration of therapy)
  • Outcome of therapy

Knowledge of current nonprescription medications allows the pharmacist to determine whether drug interactions may occur between prescribed and self-administered medications, whether the patient is self-medicating to relieve an adverse drug reaction from a prescribed medication or in an attempt to obtain better relief from symptoms than that provided by the prescribed regimen, and whether a nonprescription medication is the cause of a patient's complaint or is exacerbating a concurrent medical condition.

Past Nonprescription Medications

  • Name (proprietary and nonproprietary) and/or description

Dosage form (e.g., tablet, capsule, liquid, topical formulation)

Size, shape, and color of the dosage form

Any words, letters, and numbers on the dosage form that the patient can remember or that can be seen on the dosage form

  • Dose (recommended/prescribed and actual, and reason for discrepancy)
  • Dose schedule (routine times patient taking each dose, recommended/prescribed and actual, and reason for discrepancy)
  • Reason for taking the medication (including clarification any discrepancies regarding customary uses of medications with the prescriber)
  • Start date (exact date, duration of therapy)
  • Stop date (exact date, duration of therapy)
  • Reason for stopping
  • Outcome of therapy

Knowledge of past nonprescription regimens gives the pharmacist insight regarding past medical problems or attempts to treat current medical problems.

Current and Past Complementary and Alternative Medicines

  • Name (proprietary and nonproprietary) and/or description

Dosage form (e.g., tablet, capsule, liquid, topical formulation)

Size, shape, and color of the dosage form

Any words, letters, and numbers on the dosage form that the patient can remember or that can be seen on the dosage form

  • Dose (recommended/prescribed and actual, and reason for discrepancy)
  • Dose schedule (routine times patient taking each dose, recommended/prescribed and actual, and reason for discrepancy)
  • Reason for taking the medication (including clarification any discrepancies regarding customary uses of medications with the prescriber)
  • Start date (exact date, duration of therapy)
  • Stop date (exact date, duration of therapy)
  • Reason for stopping
  • Outcome of therapy

Approximately 7% of Americans take complementary and alternative medicines (e.g., herbal remedies, megavitamins, homeopathic medicine, folk remedies). However, the majority of people do not discuss these therapies with their physicians. Many of these medicines interact with traditional medicines. Some have significant side effects. Therefore, it is important to document the use of these medicines.

Ask the patient follow-up questions to clarify why the patient is taking the alternative medicine. For example, if a patient states that he or she is taking an alternative medicine to boost the immune system, ask the patient whether anyone has ever told the patient that he or she has a weakened immune system and whether the patient gets more infections than most people.

Medication Allergies

  • Drug name (proprietary and nonproprietary) and/or description

Dosage form (e.g., tablet, capsule, liquid, topical formulation)

Size, shape, and color of the dosage form

Any words, letters, and numbers on the dosage form that the patient can remember or that can be seen on the dosage form

  • Dose (recommended/prescribed and actual, and reason for discrepancy)
  • Date of reaction
  • Description of reaction
  • Treatment for the raction

Many physicians, nurses, and other health care professionals as well as patients may be unable to differentiate between a drug allergy and an adverse drug reaction. But it is very important to try to distinguish between the two reactions. Once a medication allergy is documented for a patient, it is highly unlikely that the patient will receive the medication or a similar medication again. If the reaction was a manageable or acceptable adverse reaction rather than an allergic reaction, however, the patient may be unnecessarily denied access to potentially useful medications. The term allergy indicates hypersensitivity to specific substances. Drug-induced allergic reactions include anaphylaxis, contact dermatitis, and serum sickness.

A useful first step is to ask patients whether they are allergic to any medications and then probe for the details of the problem, depending on the response. Ask patients if they have ever experienced rashes or breathing problems after taking any medications. Patients may not correlate a rash with an allergy, so it is important to probe for these details.

After a medication has been identified as the cause of an allergic reaction, ask the patient to provide details regarding the time or date of the allergic reaction and any interventions instituted to manage the reaction, and inquire whether the patient has received the medication since first experiencing the allergic reaction. Ask whether medications in similar drug classes have been taken without the occurrence of a similar reaction (i.e., “Have you taken any antibiotics since you found out you were allergic to penicillin?”).

Adverse Drug Reactions

  • Drug name (proprietary and nonproprietary) and/or description

Dosage form (e.g., tablet, capsule, liquid, topical formulation)

Size, shape, and color of the dosage form

Any words, letters, and numbers on the dosage form that the patient can remember or that can be seen on the dosage form

  • Dose (recommended/prescribed and actual, and reason for discrepancy)
  • Date of reaction
  • Description of reaction
  • Treatment for the raction

Ask patients whether they have ever taken a medication they would rather not take again. This question often elicits specific descriptions of adverse reactions the patient has experienced.


Immunizations

  • Name of vaccines
  • Date each vaccine was administered

Vaccinations are important for the health of individuals and the public. The CDC immunization recommendations are complex and difficult for an individual patient to understand.

Adherence

One of the goals of the medication history interview is to determine whether the patient is adherent to prescribed or recommended medication regimens. Knowledge regarding patient adherence is useful in evaluating the effectiveness of prescribed or recommended medication regimens. Medications may be ineffective if the patient does not comply with the prescribed or recommended regimen. Nonadherence may result in additional diagnostic evaluations, procedures, hospitalizations, and unnecessary combination medication regimens.

Adherence is difficult to determine through direct questioning. Patients know they are supposed to take their prescribed and/or recommended medications. When confronted by an authority figure, patients most likely will say they are adherent even if they are not. Therefore evaluate the patient's adherence by gentle probing throughout the interview. Clues about adherence may be obtained through patient descriptions of how they take their prescribed medications. Many patients can describe their medication routines in detail; other patients may not be able to describe any sort of routine or even recall the color or shape of the medication. Patients who can convincingly describe their medication routines are more likely to be adherent than patients who can provide only vague and general descriptions of their medications and routines.

Sympathetic confrontation may help the pharmacist obtain information regarding patient adherence. Patients are more likely to be truthful when describing their difficulties with complying with the medication regimen if the pharmacist acknowledges that the dosage regimen is complex and difficult to follow and that taking medication regularly is hard. Remain nonjudgmental when assessing patient adherence; this attitude encourages the patient to trust the pharmacist and tell the truth about adherence to prescribed medication regimens.