New concerns about the possibility of severe side effects related to the use of the liquid formulation of the protease inhibitor, amprenavir (Agenerase), has prompted the manufacturer Glaxo Wellcome to issue a letter outlining the safety concerns.

Of concern is the large amount of propylene glycol contained in liquid Agenerase. Propylene glycol is added to Agenerase to help the drug dissolve more easily. Propylene glycol is difficult for some people to metabolize and can accumulate -- increasing the risk of adverse events. Glaxo Wellcome has changed the labeling information that will be included with Agenerase to address the potential safety concerns.

In the letter sent to providers, Glaxo Wellcome stated that, "ANGENERASE Oral Solution is contraindicated in infants and children below the age of four years, pregnant women, patients with hepatic or renal failure, and patients treated with disulfiram or metronidazole." The letter also warned that "certain ethnic populations (Asians, Eskimos, Native Americans) and women may be at increased risk" of adverse events.

Glaxo Wellcome also recommend that people taking the liquid Agenerase be closely monitored for the following adverse events "seizures, stupor, tachycardia, hyperosmolality, lactic acidosis, renal toxicity and hemolysis." The use of alcoholic beverages should also be avoided by anyone taking the liquid form of Agenerase.