Prep 2-1-1 Missed Dose
If you miss a dose of prep, take the missed dose as soon as you remember, provided it is within 12 hours of your usual dosing time. If more than 12 hours have passed, skip the missed dose and continue with your regular dosing schedule. Make sure you keep taking one prep pill every day as this helps ensure your body stays protected even after the event. For continued prep use, the body takes several weeks to adjust to this medication. If you do miss a dose of your prep medication, there is not much need for concern.
Demetre explained that skipping just one dose should not have any effect on the level of hiv transmission protection prep provides. There is no solid research yet about the effect of missed.