AIDS: Four new drugs have been developed to overcome the limitations of the currently available anti-HIV drugs, including inconvenient schedules, side effects, and drug interactions. It is hoped that abacavir, efavirenz, adefovir dipivoxil, and amprenavir will be widely available in the near future. Abacavir, a nucleoside reverse transcriptase inhibitor with a twice-daily schedule, offers good bioavailability and generally mild side effects. Efavirenz, a non-nucleoside reverse transcriptase inhibitor with a once daily schedule, may produce side effects such as rash and dizziness. Adefovir dipivoxil, a nucleotide analog with once daily dosing, can cause carnitine depletion and carnitine supplementation is recommended. Amprenavir, a protease inhibitor with twice-daily dosing, has rather mild side effects. Information on efficacy, availability, and resistance for each of these drugs is given.