Pfizer and FDA warn of potential carcinogen impurity in HIV drug viracept

Children who are already on the drug and are stable may continue to take Viracept, but pregnant women should be switched to an alternative antiretroviral said Pfizer and the FDA.

The drug company issued a Dear Healthcare Professional letter about the presence of an impurity, ethyl methanesulfonate (EMS), that has entered the Viracept formula during the manufacturing process. The letter also gives guidelines on the use of Viracept in pediatric patients and pregnant women.