CAMPAIGN

illustration of a light blue oblong pill in a gray circle

About PrEP as a pill: 2-1-1

San Francisco City Clinic

What is 2-1-1 PrEP

  • 2-1-1 PrEP means taking PrEP pills only on the days when you have sex, and for 2 days after.
  • You must follow a specific schedule of pills correctly for it to work.
  • You can take 2-1-1 PrEP even if you drink alcohol, use drugs, take hormones, or use birth control.

Types of sex it protects

  • 2-1-1 PrEP prevents HIV when using your penis or anus for sex.
  • It does not prevent HIV when using your vagina/front-hole or injecting drugs.

Only use Truvada or its generic

  • Truvada is the only PrEP pill you can take on the 2-1-1 schedule.
  • You can use brand-name or generic Truvada. The generic name is "emtricitabine and tenofovir DF."
  • Do not use Descovy for 2-1-1.

2-1-1 PrEP requires planning ahead

  • You must take the first dose before sex.
  • You must follow a specific schedule of pills correctly for it to work. Read more about the schedule below.
  • Some find the 2-1-1 schedule hard to follow. If the 2-1-1 schedule does not work for you, consider a different type of PrEP instead.

How to take 2-1-1 PrEP

The 2-1-1 schedule

You must follow the schedule correctly for it to work. The schedule is very specific:

  1. Take the first dose: 2 pills at once, 2 to 24 hours before sex
  2. Then take a second dose of 1 pill, 24 hours after the first dose
  3. Finally, take a third dose of 1 pill, 24 hours after the second dose

If you have sex after the second dose, keep taking 1 pill every 24 hours until 2 doses have passed since your last sex.

  • For example, if you have sex again between the second and third doses, add a fourth dose of 1 pill 24 hours after the third dose. If you have sex between the third and fourth doses, or between any later doses, keep adding more doses on this same schedule until you have had 2 doses without any sex in between.


Here is a graphic showing the 2-1-1 schedule:

Illustration of 4 light blue oblong pills in a row. 2 are bundled together. The other 2 stand solitary. The word "2 1 1" is written beneath the pills.
  • In this graphic, day 1 is the day you have sex. On day 1 you take 2 pills at once, 2 to 24 hours before sex.
  • Find more detailed information about how to take 2-1-1 PrEP directly above the graphic.

How to remember to take each dose

Each dose of 2-1-1 is 24 hours apart. Here are some ways to help you remember to take each dose:

  • Once you take a dose, set a reminder on your phone to go off in 24 hours for the next dose.
  • When the 24-hour reminder goes off, take the next dose. Keep repeating this until you have taken all your 2-1-1 doses.
  • Plan ahead. Bring a pill with you if you will be out when it is time for the next dose. You can also take the pill up to 2 hours early if that is easiest.

Missed a dose?

  • If you miss the first dose and have sex without a condom or are more than 2 hours late for any of the doses after sex, take 2 pills in a single dose and call your provider about getting PEP.
  • If you are less than 2 hours late for any of the doses after sex: take the dose as soon as you can.

Possible side effects

  • Some people have gas, nausea, or headache when taking 2-1-1 PrEP. These side effects may lessen or go away over time. If they continue and they bother you, you can consider switching to a different type of PrEP.
  • Truvada is the PrEP medication used in the 2-1-1 schedule. Truvada can cause small changes in kidney function and bone mineral density. These return to normal once you stop taking it.

Maintaining your pill supply

  • Refills are not always automatic. Contact your pharmacy for a refill before running out of your pill supply. This way, you always have pills ready when you need them.
  • Before traveling, let your healthcare provider and pharmacy know that you may need an extra refill.

Cost

  • Truvada is available as a generic medication at low or no cost.
  • If you do have costs for PrEP medication, assistance programs may help cover those.
  • For help, contact the City Clinic PrEP line at 628-217-6692.

Lab testing

  • Before starting PrEP, you will get tests for HIV, STIs, kidney function, and Hepatitis B and C.
  • While taking PrEP, you will get tested for HIV, STIs, and kidney function regularly.

Switching or stopping PrEP

Switching to daily pill-taking

  • You can switch between daily and 2-1-1 pill schedules when you want to.

Switching your type of PrEP or stopping PrEP

  • If you want to stop taking 2-1-1 PrEP, talk to a healthcare provider about other HIV prevention options. You can switch to taking PrEP pills daily using Descovy or Truvada, or take PrEP as a shot, or you can use condoms.
  • If you decide to stop PrEP altogether:
    • Before you stop, take at least 2 more daily doses of Truvada after the last time you have sex without a condom. This protects against HIV.

If you have sex without a condom while not taking PrEP

  • Call your provider within 72 hours for PEP.
  • Get an HIV test as soon as you can when restarting PrEP. This helps you be sure of your HIV status after being off PrEP. PrEP is only recommended for people who are HIV negative.

PrEP prevents HIV

More PrEP resources

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This information is provided by San Francisco City Clinic. Visit our homepage at sf.gov/cityclinic.

Information on this page last revised April 14, 2026