Pfizer warns of risks in using Viracept in pregnant, pediatric patients.Pfizer issued a "Dear Healthcare Professional Letter" to inform health care professionals of the presence of ethyl methanesulfonate (EMS), a process-related impurity in Viracept and to provide guidance on the use of Viracept in pregnant women and pediatric patients. EMS is a potential human carcinogen carcinogen: see cancer.
Agent that can cause cancer. Exposure to one or more carcinogens, including certain chemicals, radiation, and certain viruses, can initiate cancer under conditions not completely understood. . Data from animal studies indicate EMS is teratogenic ter·a·to·gen·ic
Of, relating to, or causing malformations of an embryo or a fetus.
pertaining to or emanating from teratogen. , mutagenic mutagenic
inducing genetic mutation. and carcinogenic carcinogenic
having a capacity for carcinogenesis. ; however, no data from humans exist. FDA FDA
Food and Drug Administration
n.pr See Food and Drug Administration.
n.pr the abbreviation for the Food and Drug Administration. has asked Pfizer to implement new specifications to limit the presence of EMS in Pfizer-manufactured Viracept products marked in the United States.
For pediatric patients who are stable on Viracept-containing regimens, 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 HIV (Human Immunodeficiency Virus), either of two closely related retroviruses that invade T-helper lymphocytes and are responsible for AIDS. There are two types of HIV: HIV-1 and HIV-2. HIV-1 is responsible for the vast majority of AIDS in the United States. 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 FDA work to implement the long-term EMS specification for Viracept. For pregnant women with no alternative treatment options, FDA and Pfizer agree that the risk-benefit ratio remains favorable for the continued use of Viracept.
Read the complete MedWatch 2007 Safety summary, including a link to the Dear Healthcare Professional Letter and the FDA Drug Information Page, at: http://www.fda.gov/medwatch/safety/2007/safety 07.htm#Viracept