A warning has been issued over the use of the oral solution formulation of Glaxo Wellcome's protease inhibitor amprenavir (Agenerase). The company has written to doctors in the United States, where the product is marketed, to draw attention to potential safety concerns relating to the large amount of propylene glycol in the solution.
Propylene glycol, which is included in the formulation to achieve adequate solubility of amprenavir, is metabolised by the alcohol and aldehyde dehydrogenase enzyme pathway. Glaxo Wellcome says that some patients are not able to metabolise propylene glycol adequately, leading to its accumulation and potential adverse effects. Such patients include infants and children under four years, pregnant women, patients with hepatic or renal failure and patients treated with disulfiram or metronidazole.
The company says that it has received no reports of death or serious injury attributed to propylene glycol in Agenerase oral solution, but it is now recommending that the solution should be used only when Agenerase capsules or other protease inhibitor formulations are not therapeutic options.
Amprenavir is not yet marketed in the United Kingdom but licence applications have been submitted. The drug is being used on a named patient basis.