THE MEDICATION QUESTIONNAIRE

It is important to take a complete medication history from the patient, and record it at every clinic visit.

a) Prescription medications

Find out whether the patient is taking prescription medications from more than one doctor.

b) Non-prescription medications

Many patients forget to tell their doctor about their non-prescription medications. These can be extremely important causes of drug toxicity, and are occasionally involved in drug interactions.

Specific categories of drugs to inquire about include:

i)    Over-the-counter drugs (antacids, analgesics, H2 antagonists, etc.).
ii)   Health foods and vitamins
iii)  Alternative medicines (herbal, homeopathy etc.)
iv)  Drugs of abuse, illicit drugs.

c) Food and timing of meals

Many medications need to be carefully timed with regard to meals or food to maximise bioavailability. Furthermore, some foods have been shown to alter the pharmacokinetics of certain drugs. For example, in large quantities, grapefruit juice is a significant inhibitor of cytochrome P450 3A4, and can raise the concentrations of saquinavir by up to 3-fold.
Two additional questions to ask the patient are:

i)    Is the patient aware of the fed/fasting requirements for the medications he or she is       taking?
ii)  Does the patient have any unusual dietary habits that might affect the drugs he or she is       taking?

2 Can the patient identify what drugs he/she is taking?

It may be worthwhile to visually inspect all medications the patient is taking. It is good to ensure that what the patient is actually taking, and what they think they are taking, are one and the same. For example, the names nevirapine and nelfinavir are very confusing.

a) Assessing adherence

Partial adherence is extremely common. Evaluating drug interactions requires knowledge of how much medication the patient has taken, and when. A neutral approach to adherence history is preferred. Open-ended questions may prove more helpful than close-ended questions.

b) How important is non-compliance, underdosing, overdosing, and altered dose intervals?

For antiretroviral agents, good adherence is very important in assuring long-term anti-HIV activity and preventing resistance. In addition, increasing or decreasing drug dose, or increasing or decreasing dosing interval, may have a major impact on drug interactions. The impact can be significant, as most drug interactions are a direct function of drug concentration over time. This is especially true for metabolic inhibition interactions, and pharmacodynamic interactions.

c) What are some strategies to increase adherence with the regimen?

A thorough understanding of HIV therapy, including the importance of good adherence and the dangers of poor adherence, is an important basic tool to increasing adherence. Diaries and calendars may improve adherence. Learning the patients' daily routine and incorporating dosing cues into that routine may also increase adherence. The construction of a regimen using the minimum number of agents, using combination products (e.g. Duovir), and selecting drugs which are given once or twice-daily may be useful. It is also important to provide positive feedback for a successful response.

4 Does the patient understand the effects and side effects of all the    medications that have been prescribed?

It is important that the HIV physician counsel patients about what they can expect and what they need to know, when starting a new medication. For example, a patient initiating therapy with ritonavir should be extensively counseled on the gastrointestinal side effects that are likely to occur, especially during the first few weeks of therapy. Such information can greatly increase adherence to the regimen.

Many of the medications used in the management of HIV infection have overlapping side effects. Patients should be counseled about the signs and symptoms of adverse effects (such as numbness and tingling in the extremities with peripheral neuropathy), and instructed to contact their physician if any of these symptoms occur.