Overview of different PrEP dosing regimens used in PrEP trials
| PrEP dose regimen | Dose regardless of sexual activity | Pre-exposure dose | Postexposure dose | Adherence | Efficacy |
|---|---|---|---|---|---|
| Daily (PROUD, ADAPT)5 7 | 1 pill/day (24 hours apart) | N/A | N/A | No direct measure. | High |
| Event-Driven (1) (IPERGAY)6 | N/A | 2 pills, 2–24 hours before sex act; 1 pill if last pill taken <7 days ago | 2 pills, every 24 hours after the last pill; to be prolonged until 48 hours after the last sex act | Correct use (at least 1 pill taken <24 hours before sex act, and 1 24 hours after); No use (no pills 48 hours before and after sex act); Suboptimal use (any other use). | High |
| Event-driven (2) (ADAPT)7 | N/A | 1 pill, 24–48 hours before sex act (or sooner if needed); no pill if last pill taken <48 hours ago | 1 pill <2 hours after first penile sex act and not to be taken again that day | Sex act is covered if at least one pill <96 hours before sex act and 1 <24 after. | Under investigation |
| Time-driven (ADAPT)7 | 2 pills/week (3–4 days apart) | N/A | 1 pill <2 hours after first penile sex act and not to be taken again that day; no pill if twice-weekly dose has already been taken that day | Sex act is covered if at least 1 pill <96 hours before sex act and 1 <24 hours after. | Under investigation |
N/A, not applicable.