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Pharmacy Focus

Warning Issued on Use of Viracept in Pregnant Women and Pediatric Patients

Pfizer has issued a letter to healthcare professionals to inform them of the presence of a process-related impurity, ethyl methanesulfonate (EMS), in Viracept and to provide guidance on the use of Viracept in pregnant women and pediatric patients.

Data from animal studies indicate EMS is teratogenic, mutagenic and carcinogenic; however, no data from humans exist. The FDA has asked Pfizer to implement new specifications to limit the presence of EMS in Pfizer-manufactured Viracept products marketed in the United States.

For pediatric patients who are stable on Viracept-containing regimens, the FDA and Pfizer agree that the benefit-risk ratio remains favorable and those patients may continue to receive Viracept. Pediatric patients who need to begin HIV treatment should not start regimens containing Viracept until further notice.

Pregnant women who need to begin antiretroviral therapy should not be offered regimens containing Viracept until further notice. As a precautionary measure, pregnant women currently receiving Viracept should be switched to an alternative antiretroviral therapy while Pfizer and the FDA work to implement the longterm EMS specification for Viracept. For pregnant women with no alternative treatment options, the FDA and Pfizer agree that the risk-benefit ratio remains favorable for the continued use of Viracept.

For more information, please click here for a PDF copy of Pfizer's Dear Healthcare Professional Letter regarding the use of Viracept.