Even after the release of zidovudine/lamivudine/abacavir (AZT/3TC/ABC, Trizivir) and the subsequent approval of the fixed-dose combination of zidovudine/lamivudine (AZT/3TC, Combivir), the estimated incidence of this reaction has been somewhat variable.
Most cases of hypersensitivity reaction have been reported during the first 6 weeks after an abacavir-containing regimen is initiated, with a median onset time of 9 days.