Adverse effects of drugs used in the management of opportunistic infections associated with HIV infection.

Pneumocystis carinii pneumonia (PCP) is one of the most common AIDS-defining diagnoses. First-line therapy is cotrimoxazole (trimethoprim-sulfamethoxazole), despite a high incidence of toxic effects, and a greater incidence of hypersensitivity reactions among HIV-positive patients compared with the seronegative population. Alternative agents such as intravenous pentamidine, or clindamycin with primaquine, and trimethoprim with dapsone, also have a wide range of serious adverse effects, but remain treatment options. Atovaquone appears promising for the treatment of both PCP and toxoplasmosis, and has a lower reported incidence of toxicity than the alternative agents. The most toxic antifungal drugs are reserved for serious infections, such as cryptococcal meningitis. Liposomal amphotericin B has less renal toxicity than standard formulations, and exemplifies that new formulations of existing drugs, although often expensive, may have a better adverse effect profile. There are 2 different drugs currently available for cytomegalovirus (CMV) infections, ganciclovir and foscarnet. Both have a high incidence of serious adverse effects; ganciclovir mainly causes bone marrow toxicity and foscarnet leads to renal toxicity. The drugs used for mycobacterial infection (including mycobacteria as well as tuberculosis) have a wide range of adverse effects, particularly skin rashes and drug-induced hepatitis. Some of these compounds are quite new, such as rifabutin and clarithromycin, and it is important to be ever vigilant for previously unreported adverse effects.