Indications: Treatment of HIV infection in combination with other agents. Contraindications: Known or suspected hypersensitivity. Dosage: 300 mg po bid. Also available as Trizivir, a fixed dose combination of ZDV 300 mg, 3TC 150 mg, and abacavir 300 mg. Toxicity: Four percent of patients develop a hypersensitivity reaction, usually within 6 weeks of initiating therapy. It is manifested by fever, constitutional or respiratory symptoms, gastrointestinal intolerance, and/or rash. Stopping the drug leads to rapid resolution of symptoms. Never rechallenge a patient thought to have had a hypersensitivity reaction to abacavir as severe reactions and death have been reported. Other side effects include nausea, vomiting, diarrhea, headache, malaise. Pregnancy category C.