Post-exposure prophylaxis for HIV

Exposures

• Can be sexual or non-sexual; consensual or non-consensual; and heterosexual or homosexual

Risk Assessment

Level	Exposure	Estimated risk per act %
Very high	Transfusion	92.5
High	Anal (receptive)	1.38
	Needle sharing	0.63
Moderate	Anal (insertive)	0.11
	Vaginal (receptive)	0.08
	Vaginal (insertive)	0.04
Low	Oral sex (giving)	—
	Oral sex (receiving)	—
	Oral-anal contact	—
	Sharing sex toys	—
	Blood on compromised skin	—

Investigations

• HIV testing at baseline and 12 weeks
• HAV-Ab, HBsAg/sAb/cAb at baseline
• HCV-Ab at baseline and 12 weeks
• Gonorrhea and chlamydia of urine, throat, and rectum at baseline and 12 weeks
• Sypthilis at baseline and 12 weeks
• CBC at baseline
• ALT and creatinine at baseline, repeated at 2 weeks if abnormal
• Pregnancy test at baseline

Treatment

• Screen for sexual assault, counsel about safe sex
• Start treatment within 72 hours
• Tenofovir/emtricitabine 300/200 with raltegravir 400 BID, for 28 days
  • Preferred alternatives include TDF/FTC with darunavir/ritonavir or dolutegravir
  • Other alternatives include many
• Don't forget above screening

Follow-up

• Initial visit; follow-up at 4-6 weeks; then repeat bloodwork at 4 months
• Take advantage of the opportunity to counsel patients on STIs, substance use, etc.

Further Reading

• Tan et al. Canadian guideline on HIV pre-exposure prophylaxis and nonoccupational postexposure prophylaxis. CMAJ 2017;189(47):e1448-e1458.