Anaphylaxis after rechallenge with abacavir

Abacavir is a new nucleoside analogue recently approved in the United States, with good oral bioavailability and central nervous system penetration. It may be one of the most potent reverse transcriptase inhibitors with a median viral load reduction of 1.48 to 1.84 log sub(10) copies/ml after 4 weeks of monotherapy. We report this case of anaphylaxis to emphasize that rechallenge with abacavir after a hypersensitivity reaction can be fatal and should be avoided. If the diagnosis of abacavir-induced hypersensitivity reaction is unclear and HIV treatment options are limited, rechallenge should be performed with extreme caution and only in a supervised setting.