PrEP HIV Prevention

There's more than one way to prevent HIV

If you are concerned about your risk for HIV, consider Pre-Exposure Prophylaxis (PrEP), a once a day pill, to reduce the risk of getting HIV from sex by more than 90% when taken consistently. 

What is PrEP?

PrEP stands for Pre-Exposure Prophylaxis. It is an HIV prevention option that works by taking one pill every day. PrEP can help prevent you from getting HIV if you are exposed to the virus. Some people are exposed to HIV through sexual activity or injection drug use.

How does PrEP work?

PrEP is available as the medication Truvada® which contains the HIV medications
tenofovir and emtricitabine.

Studies have shown that PrEP decreases the risk of getting HIV from sex by more than 90% when taken consistently.


  • When people start taking PrEP but do not take it every day or skip doses, it is less effective in preventing HIV.
  • It can take up to 7 days for men and 21 days for women to have full protection from PrEP.
For more information about PrEP, see the following websites:

What happens after I start PrEP?

Once you are started on PrEP, it is very important that you take the pill every day around the same time of day.

Some people who start PrEP can have some minor side effects such as stomach upset and headache. These side effects usually go away in the first month.

It is very important that you follow up with your healthcare provider every 3 months for labs and prescription
refills. At those appointments, your doctor will screen you for HIV and other sexually transmitted infections.

Tell your provider if you have difficulty remembering to take your pill, if you are experiencing side effects, or want to stop PrEP.

How Can I Start PrEP?

Talk with your Tufts Medical Center Primary Care - Boston doctor or healthcare provider to
determine if PrEP is right for you.

If you do not have a healthcare provider, do not feel comfortable talking to them about PrEP, or they do not feel comfortable with prescribing it, there are trained doctors in the Tufts Medical Center Infectious Diseases Clinic that prescribe PrEP.

If you and your doctor decide that PrEP is a good option for you they will provide medication counseling and have labs drawn before giving you a prescription for PrEP.