PrEP (pre-exposure prophylaxis) is a medication that can be taken on a regular basis to reduce the risk of getting infected with human immunodeficiency virus (HIV), the disease that leads to acquired immunodeficiency syndrome (AIDS).

According to, studies show that PrEP reduces the risk of getting HIV by more than 90% when used consistently. It is even more effective when combined with condoms and other safe-sex practices. For people who inject drugs, PrEP reduces the risk by 70% when used consistently.

How PrEP Works

PrEP is an antiretroviral drug that builds up in your bloodstream. After seven days, there is enough to keep HIV from attaching to your cells’ DNA. It is important to take your dose at about the same time every day to maintain the level of  PrEP in your body.

Who Should Take PrEP

If you are HIV-negative and at high risk of HIV infection, you should consider PrEP. Some examples include:

  • You are HIV-negative and in a relationship with someone who is HIV-positive.
  • You are HIV-negative, have multiple sexual partners and don’t know their HIV status.
  • You are HIV-negative and have injected drugs or shared needles.

To start PrEP, talk with your provider about a prescription. Your provider will ask about your lifestyle. Answer honestly to help your doctor make the appropriate recommendations.

Once you are on PrEP, you should see your provider every three months to monitor your health and refill your prescription.

HIV PrEP Risks

PrEP works if you are HIV-negative. You will need to be tested regularly to make sure you are not infected. If you are HIV-positive, you run the risk of infecting your partner. HIV is most effectively treated in its early stages, so you would also run the risk of delaying your HIV treatment. If you have flu-like symptoms, please tell your provider.

PrEP does not protect against pregnancy or sexually transmitted infections, such as gonorrhea or chlamydia.

You need to take PrEP every day. If taking regular medication is difficult for you, PrEP may not be right for you. If you miss a dose, take your pill as soon as you remember. If you are close to the next dose time, take that dose and contact your provider. Do not double your dose.

When you start taking PrEP, you may experience side effects such as nausea, dizziness, headaches, fatigue and stomach cramps. These should subside after a few weeks. Try taking the pill at different times of the day and before, during or after meals. If the symptoms continue, contact your provider about how to manage them. It is important to contact your provider before you stop taking PrEP.

More PrEP Resources

For more information on PrEP and HIV prevention, please visit