Postexposure Prophylaxis for HIV Infection

Laboratory Tests Generally Recommended for Persons after Exposure to HIV *
Test	Baseline	Symptom-Directed †	4-6 Wk	12 Wk	24 Wk
ELISA for HIV antibodies	Yes	Yes	Yes	Yes	Yes
Creatinine, liver function, and complete blood count with differential count	Yes	Yes	No	No	No
HIV viral load	No	Yes	No	No	No
Anti-HBs antibodies	Yes ‡	No	No	No	No
HBsAg	Yes ‡ §	No	No	No	No
HCV antibodies	Yes	No	Yes	Yes	Yes
HCV RNA ¶	No	Yes	Yes	Yes	Yes
Screening, including rapid plasma reagin test, for other sexually transmitted infections ‖	Yes	Yes	No	Yes	Yes

* Patients who receive zidovudine plus lamivudine-based regimens should have a complete blood count and measurement of liver-enzyme levels at 2 weeks of treatment, irrespective of the presence or absence of clinical symptoms.
Tenofovir plus emtricitabine-based regimens generally involve few side effects, and symptom-directed assessment of serum creatinine or liver-enzyme levels should be considered.
The addition of a ritonavir-boosted protease inhibitor should be followed by symptom-directed assessment of liver-enzyme levels, serum glucose levels, or both.
Anti-HBs antibodies denotes hepatitis B virus surface antibodies, ELISA enzyme-linked immunosorbent assay, HBsAg hepatitis B surface antigen, and HCV hepatitis C virus.
† Symptom-directed tests are for signs or symptoms of toxic effects (rash, nausea, vomiting, or abdominal pain) or HIV seroconversion (fever, fatigue, lymphadenopathy, rash, or oral or genital ulcers)
‡ If tests for anti-HBs antibodies and HBsAg are both negative, a vaccination series against HBV infection should be initiated and completed.
§ If the patient is HBsAg-positive, he or she should have monthly follow-up of liver-function tests after discontinuation of postexposure prophylactic regimens containing tenofovir, lamivudine, or emtricitabine; referral to a specialist in viral hepatitis should be considered.
¶ HCV RNA testing may identify early HCV seroconversion; early detection and treatment during acute HCV infection may avert or ameliorate chronic disease.
‖ Rapid plasma reagin testing and testing of urethral-swab and rectal-swab specimens for gonorrhea and chlamydia and of pharyngeal-swab specimens for gonorrhea should be performed as appropriate, according to the patient's sexual risk-taking behaviors and the type of exposure to HIV.

Regimens for 28-Day postexposure Prophylaxis for HIV infection *
Two-drug regimens
Regimen	Dose	Daily Pill Burden †	Advantages	Disadvantages
Tenofovir-emtricitabine (Truvada) ‡	One tablet (300 mg of tenofovir with 200 mg of emtricitabine) once daily	1	Well tolerated; once-daily dosing	Potential nephrotoxicity
Zidovudine-lamivudine (Combivir) §	One tablet (300 mg of zidovudine with 150 mg of lamivudine) twice daily	2	Preferred in pregnancy	Twice-daily dosing; less well tolerated than tenofovir-emtricitabine (nausea, asthenia, neutropenia, anemia, abnormal liver enzyme levels)
Three-drug regimens ¶
Ritonavir-lopinavir (Kaletra) (plus either tenofovir-emtricitabine or zidovudine-lamivudine)	Two tablets (50 mg of ritonavir with 200 mg of lopinavir per tablet) twice daily, or four tablets once daily	5 or 6	Either once-daily or twice-daily dosing; one copayment; no refrigeration required; most experience in pregnancy; high genetic barrier to resistance	Gastrointestinal side effects such as diarrhea; may cause elevated liver enzyme levels or hepatitis
Ritonavir plus atazanavir (plus either tenofovir-emtricitabine or zidovudine-lamivudine)	100 mg of ritonavir plus 300 mg of atazanavir once daily	3 or 4	Once-daily dosing; well tolerated	Ritonavir must be refrigerated; potential for asymptomatic jaundice, renal stones; may cause elevated liver-enzyme levels or hepatitis
Ritonavir plus darunavir (plus either tenofovir-emtricitabine or zidovudine-lamivudine)	100 mg of ritonavir plus two tablets, each containing 400 mg of darunavir, once daily	4 or 5	Once-daily dosing; high genetic barrier to resistance	Ritonavir must be refrigerated; gastrointestinal side effects; may cause elevated liver-enzyme levels or hepatitis

* Tenofovir, emtricitabine, and lamivudine all have activity against hepatitis B. Patients with chronic active hepatitis B (i.e., patients who are positive for hepatitis B surface antigen) may have flares of hepatitis on withdrawal of these agents at the completion of postexposure prophylaxis treatment. Referral to a hepatitis specialist or serial monthly monitoring of liver-enzyme levels for up to 6 months after treatment should be considered.
† The daily pill burden in the three-drug regimens depends on which two-drug regimen is chosen.
‡ The dose of tenofovir-emtricitabine should be reduced to one tablet every 48 hours in patients with a creatinine clearance of 30 to 49 ml per minute. Tenofovir-emtricitabine is not recommended in patients with a creatinine clearance of less than 30 ml per minute or in patients who are undergoing hemodialysis.
§ Zidovudine-lamivudine is not recommended in patients with a creatinine clearance of less than 50 ml per minute.
¶ The boosting agent ritonavir is not considered to be an active drug in tabulating the number of agents in the three-drug regimen.