United States of America - The manufacturer of amprenavir (Agenerase®, Glaxo Wellcome) has issued a warning concerning a potential risk associated with the amount of propylene glycol present in the oral solution formulation. Amprenavir is a pro-tease inhibitor indicated for the treatment of HIV infection in combination with other antiretroviral agents in patients 4 years of age and older.

Propylene glycol is metabolized by an enzyme pathway which does not attain equivalent adult activity until 12 to 30 months of age. Infants and children below the age of 4 years, pregnant women, patients with hepatic or renal failure, and patients treated with disulfiram or metronidazole are not able to adequately metabolize and eliminate propylene glycol, leading to its accumulation.

Although no reports have been received of serious injury or death, potential safety concerns exist due to the high propylene glycol content of amprenavir. It is therefore advisable to use amprenavir capsules or other protease inhibitor formulations in preference to the oral solution in those patients at risk.

Reference: Letter from GlaxoWellcome Inc. at www.fda.gov/medwatch