Pre-exposure prophylaxis for HIV

Background

• Principle: give HIV meds to high-risk individuals to prevent seroconversion if exposed
• Works when adherent, but adherence is often poor

Management

Assessing Eligibility

• MSM: condomless anal sex within the last 6 months, and any of:
  • Sexually transmitted infection within the last 12 months
  • Recurrent use of HIV PEP at least twice
  • Ongoing sexual relationship with an HIV-positive partner who has a detectable viral load or is not on treatment
    • Stop if partner is undetectable for 6 months
  • HIV incidence risk index for men who have sex with men (HIRI-MSM) ≥11
• Heterosexual exposure
  • Ongoing condomless sexual relationship with an HIV-positive partner who has a detectable viral load or is not on treatment
    • Stop if partner is undetectable for 6 months
  • Can be considered even if condomless sexual relationship with an HIV-positive partner with low risk
• People who inject drugs
  • Consider if they share drug paraphernalia with someone who has risk of HIV
  • People who inject drugs may not benefit as much

Baseline Investigations

• HBV (sAb, sAg, and cAb); HCV; and HAV, so you can vaccinate
• STI screening
  • Syphilis, chlamydia, and gonorrhea
  • Urethral, pharyngeal, and rectal
• Vaccinations
  • HAV and HBV, if not immune
  • HPV, if eligible

Treatment

• First-line, continuous: Tenofovir disoproxil fumarate/emtricitabine 300 mg/200 mg daily
• Alternative, continuous: tenofovir alafenamide/emtricitabine 25 mg/200 mg PO daily
• Alternative, on-demand: tenofovir disoproxil fumarate/emtricitabine 300 mg/200 mg taken 2 to 24 hours before first exposure and continued daily until 48 hours after last exposure
• Continuous prophylaxis should be prescribed for 3 months at a time without repeats, with follow-up every 3 months to give a new prescription
• Counsel on condom use and side effects
• Connect to mental health and other services, if indicated

Follow-up

• Follow-up after 30 days and then every 3 months thereafter

Item	Baseline	30 days	q3mo	q12mo
Clinical Evaluation
Symptoms of HIV seroconverion	X	X	X
PrEP adherence and side effects		X	X
Assess indication for PrEP	X	X	X
Counsel on prevention of HIV and STIs	X	X	X
Assess and manage other syndemic conditions, including drug and alcohol use	X	X	X
Laboratory Evaluation
HIV test	X	X	X
Hepatitis A immunity	X
Hepatitis B screen	X			if unvaccinated
Hepatitis C screen				X
Screen for gonorrhea and chlamydia	X		X
Syphilis serology	X		X
CBC	X		X
Creatinine	X	X	X
Urinalysis	X
Pregnancy test (if appropriate)	X		X

Further Reading

• Canadian guideline on HIV pre-exposure prophylaxis and nonoccupational postexposure prophylaxis. CMAJ. 2017;189(47):e1448-e1458. doi: 10.1503/cmaj.170494