Why is PrEP important?
PrEP, or Pre-Exposure Prophylaxis, is an important tool to reduce HIV risk among individuals who may be at high risk for HIV infection. It includes a combination of anti-HIV medicines, including tenofovir and emtricitabine (TDF/FTC), sold under the name Truvada® (pronounced tru vá duh).
Does PrEP work?
Clinical studies have demonstrated that PrEP is both safe and effective among a range of individuals, including heterosexually active men and women, men who have sex with men (MSM), transgender (TG) women who have sex with men, and people who inject drugs (PWID). Higher rates of adherence is associated with better efficacy.
- Among MSM and TG women who have sex with men, TDF/FTC has reduced the risk of HIV infection by more than 90% among those with high rates of adherence.
- In heterosexual HIV-discordant couples, TDF/FTC was 75% effective overall in reducing HIV transmission to the uninfected partner, and 90% effective in those with the highest levels of adherence.
- In heterosexual single women and men, TDF/FTC PrEP reduced HIV infection rates by 62-85%, with efficacy again closely related to adherence.
- In PWID, use of oral TDF PrEP was associated with a 49% reduction in HIV infection.
What are side effects of PrEP?
Side effects of TDF/FTC include GI symptoms (nausea, diarrhea, abdominal discomfort) and headache. These are relatively uncommon and usually resolve within weeks of PrEP initiation. Renal dysfunction and bone loss have been reported. For patients who become infected with HIV while on TDF/ FTC or those who are infected at the time PrEP was initiated, viral resistance to the PrEP drugs may occur.
How do I screen patients for PrEP?
Assess current and recent sex and drug-use behaviors, symptoms indicative of a possible HIV infection, and intentions to become pregnant.
HIV negative status must be confirmed within 1 week of PrEP initiation, ideally with a 4th-generation Ag/Ab test if possible, because these are most sensitive to acute/recent HIV infection; oral rapid tests are not recommended.
Heptitatis B testing must be done; if negative, vaccination should occur; if positive, consult with an HIV or HBV specialist before initiating PrEP, as both TDF and FTC are active against hepatitis B, and special considerations apply.
Renal impairment should be ruled out. TDF/FTC PrEP should not be given to persons with creatinine clearance (CrCl) less than 60 mL/min, and should be used only with caution and extra monitoring in persons with CrCL 60-90 mL/min.
Mental health issues should be assessed. Refer for mental health or substance-use care if indicated.
Symptoms of acute HIV infection should be monitored on an ongoing basis, including:
- Night sweats
How do I prescribe PrEP?
TDF/FTC should be prescribed as 1 pill orally once daily. It is estimated that it takes 2-3 weeks before TDC and FTC levels are protective, and patients should be particularly attentive to reducing risk with other methods (e.g., condom use).
Giving a 90-day supply with no refills is recommended, since it is important to reassess a patient’s HIV status and risk before a new prescription is given. This includes history, lab evaluation, and education and counseling.
When should PrEP be discontinued (it is best to continue PrEP for 28 days beyond the last potential HIV exposure)
- A person’s risk decreases substantially and PrEP is no longer deemed necessary
- Side effects are not tolerable
- Poor adherence
- Patient tests positive for HIV- stop PrEP immediately and refer patient urgently to HIV care