PrEP 2-1-1 for Anal Sex

What is PrEP 2-1-1?

Rather than taking Truvada once daily, PrEP 2-1-1 involves taking PrEP medication around times of anal sex instead of once per day. PrEP 2-1-1 is named for its schedule of dosing: You take two pills 2-24 hours before sex, one pill 24 hours after the initial dose, and one final pill 24 hours later. If you have sex more than 24 hours after taking your first dose (two pills), or over multiple days, you will need to continue taking one pill every day until you have taken two doses following your last anal sex encounter, at which point you can stop taking tablets.

Because PrEP 2-1-1 is taken around times of anal sex instead of every day, PrEP 2-1-1 might make sense for people who have sex less frequently.

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How Does PrEP 2-1-1 work?

This downloadable PDF explains the difference between Daily PrEP and PrEP 2-1-1 for anal sex, and offers an explanation of the dosing strategy for PrEP 2-1-1.


Clinicians only recommend PrEP 2-1-1 for people having anal sex, since the drug may not be present in levels high enough with PrEP 2-1-1 dosing to protect vaginal tissues. In studies with men who have sex with men, PrEP 2-1-1 has been found to be effective in preventing HIV infection when used correctly.


PrEP 2-1-1 has been extensively studied and is known to be effective at preventing HIV infection for people having anal sex. However, the strategy has not been reviewed by the FDA in the U.S., which is one reason many people may not know about it.

PrEP 2-1-1 is endorsed by the country-wide health organizations of France, Australia and Canada. As of January 2019 in the U.S., the International AIDS Society in the USA (a professional medical society) and the San Francisco Department of Public Health endorse PrEP 2-1-1.

Find out how effective PrEP 2-1-1 is to prevent HIV infection.

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