Nonoccupational HIV Postexposure Prophylaxis

Abstract

To the Editor: We agree with the perspective of Drs Merchant and Mayer in their Commentary that the new Centers for Disease Control and Prevention (CDC) guidelines for provision of human immunodeficiency virus (HIV) nonoccupational postexposure prophylaxis (HIV NPEP) represents an important initial step in advising clinicians. However, we note an important caveat with regard to the choice of antiretroviral agents, as discussed in the clinical guidelines developed by the New York State Department of Health AIDS Institute (NYSDOH AI) in 1997 and updated in December 2004. The CDC now endorses 3-drug HIV NPEP regimens rather than 2-drug regimens, as does the NYSDOH AI. Yet, the CDC’s suggestion of efavirenz as an anchor of the simplest 3-drug regimens is concerning. In some resourcelimited countries, efavirenz may be the only viable option to complete a postexposure prophylaxis regimen. However, in the United States, the Food and Drug Administration recently reclassified efavirenz as a category D agent (positive evidence of fetal risk) for pregnant women. Since much of HIV NPEP is likely prescribed for women exposed to HIV through sexual assault, recommendation of 28-day therapy with a category D agent will require more attention to contraception than simply testing for pregnancy and providing emergency postexposure contraception at the time of NPEP initiation. Furthermore, the therapeutic index of efavirenz in this context seems unfavorable, since the incidence of central nervous system adverse effects approaches 25%. The alternative regimen of tenofovir, zidovudine, and lamivudine that is suggested in the NYSDOH AI guidelines for HIV NPEP may offer a potentially less toxic option that maintains a low pill burden (3 pills/d) and also is supported by at least some experimental evidence from animal models. This alternative regimen, in the context of explicit instructions and algorithms for its use (as contained in the NYSDOH AI guidelines), may better serve patients with nonoccupational exposure to HIV, especially those who have been exposed through sexual assault, as well as the practitioners asked to care for them. We also note that clinicians practicing in local jurisdictions in which HIV NPEP guidelines have been created (eg, California, Massachusetts, New York, Rhode Island) should be aware that federal guidelines do not necessarily replace or supplant local medical standards of care.