Antiretroviral Drug Interactions and Adverse Side Effects

The complexity of antiretroviral therapy, coupled with the lifelong duration of treatment, presents the need for extensive management of drug interactions and adverse effects. This article includes an extensive discussion of drug interactions involving antiretroviral agents and other medications (eg, antibiotics, oral contraceptives, H2 antagonists, and lipid-lowering agents) commonly used in individuals with HIV. Mechanisms (eg, CYP enzyme induction/inhibition) by which these interactions occur are explored and practical guidelines for dose adjustments are offered. Also included is a review of short-term and longterm adverse effects associated with antiretroviral therapy, along with commonly employed remedies. Practical and related counseling tips for pharmacists are offered throughout this article in an effort to encourage patient communication. (Adv Stud Pharm. 2008;5(4):105-113) Treatment of HIV requires lifelong medication therapy. In addition to taking medications to suppress the virus, HIV-positive patients commonly receive other agents to relieve adverse effects, to treat or prevent opportunistic infections, or to treat other chronic diseases. Often, these medications may be prescribed by multiple providers, including cardiologists, family practitioners, and obstetrician/gynecologists. As a result of these complex health issues, health systems, and polypharmacy, HIV-positive individuals are at risk for adverse effects and drug interactions. In many cases, the pharmacy is the only place where the patient’s medication list is available in its entirety, and the community pharmacist is often the last line of defense in preventing the occurrence of a drug interaction. It is, therefore, critical for pharmacists to be well informed regarding existing and emerging interactions and adverse effects of antiretroviral therapy.