Nonoccupational Postexposure Prophylaxis

Provide pretest counseling and perform a baseline HIV antibody test. Evaluate and test for other infections transmitted through sexual or IDU exposures, including chlamydia, gonorrhea, syphilis, herpes simplex virus infection, hepatitis B (HBV surface antigen, surface antibody, core antibody), and hepatitis C (HCV antibody). Obtain complete blood count (CBC), liver function tests (LFTs), and chemistry panel at baseline before treatment with ARV medications.

Follow the algorithm in Figure 1 to determine whether the patient should be offered nPEP medications. If the patient is a candidate for treatment, counsel him or her about the potential risks and benefits of nPEP. If the patient elects to start therapy, see Table 1 for potential regimens. Select a regimen that is likely to be effective but tolerable; consider the potential adverse effects of ARV agents. Note that certain ARV agents, including nevirapine, should not be used for PEP. Avoid efavirenz in pregnant women.

If the HIV status of the source person is unknown and the exposure is considered to be of relatively low risk, consider 2-drug nPEP (eg, zidovudine + lamivudine) to minimize toxicity. If the source person is known or suspected to have infection with HIV that is resistant to ARV medications, seek expert consultation in selecting an appropriate nPEP regimen.

Table 1. Antiretroviral Regimens for Nonoccupational Postexposure Prophylaxis of HIV Infection

Table 1. Antiretroviral Regimens for Nonoccupational Postexposure Prophylaxis of HIV Infection Key to abbreviations: NNRTI = non-nucleoside reverse transcriptase inhibitor; PI = protease inhibitor; hgc = saquinavir hard-gel capsule (Invirase); sgc = saquinavir soft-gel capsule (Fortovase); NRTI = nucleoside reverse transcriptase inhibitor. † Efavirenz should be avoided in pregnant women and women of childbearing potential. # Stavudine may cause a higher incidence of lipoatrophy, hyperlipidemia, and mitochondrial toxicities than other NRTIs. § Low-dose (100-400 mg) ritonavir. See Table 4 from the Adult Antiretroviral Guidelines (cited below) for doses used with specific PIs. ** Use of ritonavir with indinavir might increase the risk of renal adverse events. Source: U.S. Department of Health and Human Services. Antiretroviral Postexposure Prophylaxis After Sexual, Injection-Drug Use, or Other Nonoccupational Exposure to HIV in the United States. Table 2. MMWR Recomm Rep. 2005 Jan 21;54(RR02);1-20. Available online at aidsinfo.nih.gov/Guidelines/GuidelineDetail.aspx?GuidelineID=11. Preferred regimens NNRTI-based Efavirenz† + (lamivudine or emtricitabine) + (zidovudine or tenofovir) PI-based Lopinavir/ritonavir (co-formulated as Kaletra) + (lamivudine or emtricitabine) plus zidovudine Alternative Regimens NNRTI-based Efavirenz + (lamivudine or emtricitabine) + abacavir or didanosine or stavudine# PI-based Atazanavir + (lamivudine or emtricitabine) + (zidovudine or stavudine or abacavir or didanosine) or (tenofovir plus ritonavir [100 mg/day]) Fosamprenavir + (lamivudine or emtricitabine) plus (zidovudine or stavudine) or (abacavir or tenofovir or didanosine) Fosamprenavir/ritonavir§ + (lamivudine or emtricitabine) + (zidovudine or stavudine or abacavir or tenofovir or didanosine) Indinavir/ritonavir§** + (lamivudine or emtricitabine) + (zidovudine or stavudine or abacavir or tenofovir or didanosine) Lopinavir/ritonavir (co-formulated as Kaletra) + (lamivudine or emtricitabine) + (stavudine or abacavir or tenofovir or didanosine) Nelfinavir plus (lamivudine or emtricitabine) + (zidovudine or stavudine or abacavir or tenofovir or didanosine) Saquinavir (hgc or sgc)/ritonavir§ + (lamivudine or emtricitabine) + (zidovudine or stavudine or abacavir or tenofovir or didanosine) Triple NRTI Abacavir plus lamivudine + zidovudine (only when an NNRTI- or PI-based regimen cannot or should not be used)

Key to abbreviations: NNRTI = non-nucleoside reverse transcriptase inhibitor; PI = protease inhibitor; hgc = saquinavir hard-gel capsule (Invirase); sgc = saquinavir soft-gel capsule (Fortovase); NRTI = nucleoside reverse transcriptase inhibitor. † Efavirenz should be avoided in pregnant women and women of childbearing potential. # Stavudine may cause a higher incidence of lipoatrophy, hyperlipidemia, and mitochondrial toxicities than other NRTIs. § Low-dose (100-400 mg) ritonavir. See Table 4 from the Adult Antiretroviral Guidelines (cited below) for doses used with specific PIs. ** Use of ritonavir with indinavir might increase the risk of renal adverse events. Source: U.S. Department of Health and Human Services. Antiretroviral Postexposure Prophylaxis After Sexual, Injection-Drug Use, or Other Nonoccupational Exposure to HIV in the United States. Table 2. MMWR Recomm Rep. 2005 Jan 21;54(RR02);1-20. Available online at aidsinfo.nih.gov/Guidelines/GuidelineDetail.aspx?GuidelineID=11.

Once the decision is made to institute nPEP, do the following:

	Begin ARV prophylaxis as soon as possible after the exposure, but always within 72 hours. Treatment should be continued for 28 days.
	Provide counseling about the efficacy of nPEP, including the importance of protection against future HIV exposures, timely initiation of nPEP medications, and adherence to these medications for 28 days. Continued counseling about HIV risk reduction may be appropriate. In cases of sexual assault, refer the patient to a rape counselor.

Patients should be evaluated at 1 week for review of all test results and further risk reduction counseling. For patients taking nPEP, this follow-up should include adherence assessment and evaluation of any adverse effects. A 2-week blood screening (CBC, LFTs, and chemistry panel) should be done for patients on the 28-day nPEP regimen to monitor for nPEP toxicity. Follow-up testing for HIV antibody in patients with a negative baseline HIV antibody test should be done at 6 weeks, 3 months, and 6 months after the exposure. Some patients may also need health education counseling and emotional support during their follow-up visits. If patients develop acute HIV infection or are discovered to be HIV seropositive at follow-up testing, refer to an HIV specialist for evaluation and care (see chapter Primary HIV Infection).

Prophylaxis against HBV is recommended for patients with potential exposure to HBV who have not been vaccinated against HBV. Give HBV immune globulin (HBIG) as a 0.06 mL/kg intramuscular injection and initiate the vaccination series. For patients who received the vaccine series but did not develop protective antibody (HBV sAb+), give HBIG at the time of the postexposure workup and repeat in 1 month. For patients with immunity to HBV (HBV sAb+), no treatment is indicated.

For HCV, no recommended prophylactic treatments are available. After potential exposure, check a baseline HCV antibody test. If the source is known to have HCV infection, consider alanine aminotransferase (ALT) and HCV viral load testing at 4-6 weeks. HCV antibody testing should be repeated at 4-6 months. If HCV seroconversion occurs (indicated by ALT elevation, detectable HCV viral load, or confirmed positive HCV antibody test), refer the patient to a hepatologist because early treatment of acute HCV may be indicated.