How fast does PrEP wear off?

How fast does PrEP wear off? How long PrEP protection lasts after stopping depends on the type. Oral PrEP does not wear off immediately, drug levels decline over days. For generic Truvada and Descovy, protective intracellular drug levels can persist for several days after last dose, but they steadily fall, and protection becomes unreliable. If you have had potential HIV exposures in the week before stopping, CDC recommends continuing daily oral PrEP for at least 28 days after last possible exposure, similar to PEP duration, to cover the window. For injectable cabotegravir (Apretude), the drug has a long tail, it stays in the body for many months after last injection, slowly declining over up to 12 months or longer. During that tail, levels are too low to reliably prevent HIV but high enough to potentially allow drug-resistant HIV if infection occurs, so CDC advises transitioning to oral PrEP or other prevention within 8 weeks after missed injection. Because stopping is complex, talk to your provider before discontinuing, especially if you have ongoing risk or hepatitis B, since stopping tenofovir can cause hepatitis B flare.