PrEP Provider Toolkit

Advanced Topics

Event-Driven PrEP (ED-PrEP)

   Although the data is limited, event-driven PrEP (ED-PrEP) with F/TDF (Truvada) appears to be an efficacious alternative strategy, offering similar protection against HIV infections as daily dosing. ED-PrEP may be appropriate for patients who are MSM and do not prefer daily ingestion. There are a couple of important points to note and discuss with your patients:

Event-Driven PrEP Patient Counseling Checklist
  • ED-PrEP does not have FDA approval in the United States though existing studies show that it may be just as effective in preventing HIV infections as daily dosing
  • Only F/TDF (Truvada) should be used for ED-PrEP
  • Only indicated for individuals who are MSM to prevent HIV infections that occur sexually
  • ED-PrEP may cause more significant GI side effects
  • It should not be used if the patient has HBV infection or does not know their HBV status

The 2-1-1 Rule for PrEP on-Demand

  • Initial Dose: Take 2 pills 2-24 hours before sex
  • Second Dose: Take 1 pill 24 hours after the initial dose
  • Follow-up Doses: Take 1 pill 24 hours after the second dose (48 hours after the initial dose)
  • If sexual activity continues, take 1 pill everyday and continue for 2 days after the last sexual event.
  • Additional notes for follow-up doses:
    • If a gap of <7 days occurs between sexual event, take 1 pill everyday and continue for 2 days after the last sexual event.
    • If a patient has been off of PrEP for >7 days, restart the 2-1-1 cycle
Table 13. ED-PrEP Patient Counseling Checklist
Source: https://checkhimout.ca/what-is-prep/resources/