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Triple compared to dual anti-retroviral therapy is the most effective at reducing HIV infectivity

Three Part Question

In [an adult who has sustained a needlestick injury from a known HIV source] is [triple compared with dual anti-retroviral therapy] more effective at [preventing HIV infection]

Clinical Scenario

A very distressed medical student presented to the emergency department with a bleeding injury site following a needlestick injury sustained while trying to cannulate a known HIV source. We wondered if triple compared to dual anti-retroviral therapy is the most effective at reducing HIV infectivity.

Search Strategy

Medline 1966-July 2006 using the OVID interface.
[blood or needlestick$.tw or needle? or EXP needlestick injuries/] AND [exp. PEP or PEP .mp or exp. triple therapy or triple therapy. mp or exp. dual therapy or dual therapy m.p or exp. antiretrovirals or exp.m.p protease inhibitors or exp. zidovudine/ m.p or lamivudine .exp/ mp or indinavir exp/ mp] AND [exp. HIV or human immunodeficiency virus]
Search limited to english and human studies

Search Outcome

779 papers found, 3 papers relevant, 1 paper used

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Basset IV et al
Community members and health care workers following high risk exposure from an HIV sourceObservational studyTransmission rate (no PEP),Antiretroviral resistance rate, Toxicity, Efficacy , efficacy in resistance, NOTE. 2-drug PEP; Zidovudine and Lamivudine, 3-drug therapy; zidovudine, Lamivudine and a protease inhibitor (indinavirTransmission rate (no PEP)-0.3%, 0.006-0.5 % range in sensitivity analysis (SR), Antiretroviral resistance rate-10%,0-40 SR, 2-drug PEP: 59%, 12-88 SR, Discontinuation rate-21%, 10-50 SR, efficacy 79%, 0-100 SR, Efficacy in resistance-30%, 0-100% SR, 3-drug PEP:Toxicity 66 %, 28-88 % SR,Discontinuation rate-28%, 10-60 % SR, Efficacy 82%, 0-100% SR, Efficacy in resistance -50%, 0-100% SREthical approval not stated


Despite guidelines that frequently recommend 2-drug PEP, the most commonly prescribed regimen in the USA and in Europe use 3 drugs (16). Individual preferences may ultimately guide treatment decisions. Although the perception of HCW is that a 3-drug regimen is the more efficacious option, toxicity leading to premature discontinuation may threaten the overall efficacy of a 3-drug regimen.

Clinical Bottom Line

Two drug PEP therapy, especially in low antiretroviral resistance areas, should continue to be considered reasonable. Three drug therapy should only be used when the exposure type and source is considered to be high risk for HIV and also when antiretroviral resistance is anticipated.


  1. Basset IV, Freedberg KA,Walensky RP. Two or three? Balancing efficacy, toxicity and resistance in PEP for occupational exposure to HIV. Clinical Infectious Disease. 2004:395-401