POST-EXPOSURE PROPHYLAXIS - updated January 2023

What is PEP?

Post-exposure prophylaxis (PEP) non-professional is equivalent to the morning-after pill but not for the fear of getting pregnant but rather for the fear of becoming HIV positive following a risky sexual encounter for HIV.

Any anal or vaginal intercourse without a condom regardless of the duration of unprotected penetration (a few seconds or a few quarters of an hour) is considered high and medium risk. PEP should be offered in these circumstances.

Receptive fellatio with ejaculation is considered low risk and PEP can be considered on a case-by-case basis.

All other forms of oral sex (cunnilingus, anilingus, and insertive fellatio) are considered negligible and PEP is not recommended.

PEP should be started within the first 72 hours after the risky encounter, ideally within the first 12 hours. The sooner PEP is started, the better the outcome. It is not recommended to start PEP if 72 hours have passed.

Any man having sex with men (MSM) or transgender woman having had a risky sexual encounter with another MSM.

Any heterosexual man or woman having had a risky sexual encounter with a person from these categories:

  • MSM
  • Any intravenous or intranasal drug user at risk or sharing their equipment or using contaminated equipment
  • Any person from an HIV endemic country without knowing their HIV status
  • Any known HIV positive person without effective antiretroviral treatment or not regularly taking their medication
  • Sex worker

The effectiveness of PEP depends on the time between the risky sexual contact and the start of treatment, adherence to treatment, and its use. The shorter the delay, the better the result. Exact data for non-professional PEP are not known. For professional PEP, effectiveness is estimated at 80%.

The duration of PEP remains 28 days regardless of the molecules used.

Option used which does not appear in the update of Canadian recommendations

Biktarvy (tenofovir alafenamide (TAF) 25mg + emtricitabine (FTC) 200mg + bictegravir (BIC) 50mg) once a day for 28 days.

Genvoya (tenofovir alafenamide (TAF) 10mg + emtricitabine (FTC) 200mg + elvitegravir (ELV) 150mg + cobicistat (COB) 150mg) once a day for 28 days.

Tenofovir disoproxil fumarate (TDF) 300mg + emtricitabine (FTC) 200mg once a day for 28 days and raltegravir 400mg twice a day for 28 days (raltegravir HD 600mg 2 co once a day should not be used)

NO LONGER RECOMMENDED: despite possible alternative (weak recommendation) in the update of Canadian guidelines

The combination lopinavir/ritonavir, regardless of dosage 800/200mg orally once a day or lopinavir/ritonavir 200/50mg 2 tablets (total lopinavir 400mg/ritonavir 100mg) orally twice a day is not recommended because of very significant gastrointestinal side effects resulting in early discontinuation of post-exposure prophylaxis by patients.

Short-term side effects may include nausea, vomiting, abdominal cramps, dizziness, headaches, insomnia, or fatigue. These symptoms usually start within the first two weeks of taking TDF/FTC + 3rd agent and last only one to two weeks. Often taking the medication with food will decrease gastrointestinal symptoms. Taking TDF/FTC at bedtime reduces fatigue symptoms. Taking the 3rd agent in the morning will reduce insomnia.

Long-term and serious side effects include proximal renal tubular acidosis (Fanconi syndrome) and bone demineralization (osteoporosis/osteopenia) are very unlikely since PEP is only taken for 28 days.

Anyone who has had PEP should have follow-up with screening for sexually transmitted and blood-borne infections (STBBIs) at the end of treatment, 3 months, 6 months, and 1 year after the end of PEP.

Condom use should be part of sexual habits throughout the duration of PEP treatment and until the results of the 3-month follow-up after the end of PEP. Taking PEP may delay HIV seroconversion. In case PEP treatment is ineffective in eliminating HIV infection, condom use should last up to 3 months after the end of PEP. It is extremely unlikely for a person to have a falsely negative HIV test result beyond 3 months after the end of treatment.