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For Consumers

Updated information regarding antiretroviral agents used as HIV postexposure prophylaxis for occupational HIV exposures

From the Morbidity and Mortality Weekly Report (MMWR) <>   
December 14, 2007  / 56(49);1291-1292

In 1996, the U.S. Public Health Service first recommended using  antiretrovirals as postexposure prophylaxis (PEP) after occupational  exposure to human immunodeficiency virus (HIV) (1 <> ).  Since the updated HIV PEP recommendations in 2005 (2 <> ),  two important changes to antiretroviral use have occurred that affect the  management of occupational exposures.  

First, Kaletra® (Abbott Laboratories, Abbott Park,  Illinois), a combination protease inhibitor, is no longer available in its  original formulation: capsules containing 133 mg of lopinavir and 33 mg of  ritonavir. Although the recommended daily prescribed amount of Kaletra  ingredients is unchanged, the dosing regimen has changed as a result of  the new Kaletra formulation. The previous dosing regimen for the capsule  formulation was three capsules twice daily.Kaletra is now manufactured  only in tablet form, with each tablet containing 200 mg of lopinavir and  50 mg of ritonavir. To achieve the same recommended daily prescribed  amount of the tablet formulation, two tablets of 200 mg of lopinavir and  50 mg of ritonavir should be taken twice daily. Health-care providers  should not prescribe three tablets twice a day of the new Kaletra  formulation; that dose would be the equivalent of 1,200 mg of lopinavir  and 300 mg of ritonavir daily, a higher dose than the recommended 800 mg  of lopinavir and 200 mg of ritonavir daily.

Second, on September 10, 2007, Pfizer, Inc. issued a letter* warning  health-care providers about the use of Viracept® (nelfinavir)  (Pfizer, Inc., New York, New York), another protease inhibitor, because  the Viracept manufactured in Europe contained high levels of ethyl methane  mesylate (EMS). EMS is a byproduct of the manufacturing process and a  known animal carcinogen, mutagen, and teratogen. The level at which EMS  might become carcinogenic or teratogenic in humans is not known. The  warning in the letter applies to pregnant women and states that  information about the ability of EMS to cross the placenta or to enter  breast milk is currently unknown. A review of data from the Antiretroviral  Pregnancy Registry, which collects data on approximately 6,000  HIV-infected pregnant women, indicated that, during January 1989--January  2007, no statistically significant difference was observed in the  prevalence of birth defects among the infants of women who used Viracept  compared with those whose mothers used other antiretroviral therapies  (3). Nonetheless, the Food and Drug Administration (FDA) recommends  that pregnant women limit their exposure to EMS during pregnancy. Until  further notice, pregnant women who need to begin antiretroviral therapy or  HIV PEP should not be offered regimens containing Viracept. As a  precautionary measure, pregnant women currently receiving Viracept should  be switched to an alternative antiretroviral therapy while Pfizer and FDA  work to implement a long-term EMS specification for Viracept. Specific  recommendations for use of antiretroviral agents in pregnant  HIV-1--infected patients are indicated in the U.S. Department of Health  and Human Services guidelines (4) and can be consulted to determine  an alternative treatment option.

Because nearly 80% of U.S. health-care personnel are female (5)and many of these women are of child-bearing age, this updated information  about Viracept might be relevant to the choice of drugs included in an HIV  PEP regimen taken by female health-care personnel. Additional information and guidance regarding management of specific exposures are available from the National Clinicians' Post-Exposure Prophylaxis Hotline by telephone(888-448-4911) or online (


  1. CDC.  Update: provisional Public Health Service recommendations for  chemoprophylaxis after occupational exposure to HIV. MMWR 1996;  45:468--72. <>
  2. CDC.  Updated U.S. Public Health Service guidelines for the management of  occupational exposures to HIV and recommendations for postexposure  prophylaxis. MMWR 2005;54(No. RR-9):1--17. <>
  3. Antiretroviral Pregnancy Registry Steering Committee. Antiretroviral  Pregnancy Registry international interim report for 1 January 1989  through 31 January 2007. Wilmington, NC: Registry Coordinating Center;  2007. Available at <> .
  4. US Department of Health and Human Services, Panel on Clinical  Practices for Treatment of HIV Infection. Guidelines for the use of  antiretroviral agents in HIV-1-infected adults and  adolescents---December 1, 2007. Available at
  5. US Department of Labor, Bureau of Labor Statistics. Employed persons  by detailed industry and sex, 2006 annual average. Available at

* Available at

Richard Klein
Office of Special Health Issues
Food and Drug Administration

Kimberly Struble
Division of Antiviral Drug Products
Food and Drug Administration

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