Understanding PrEP: The HIV Prevention Pill


If you’re at high risk for contracting HIV, the HIV prevention pill can help keep you safe and infection-free. PrEP is a once-daily pill that reduces your chance of contracting HIV from sex by more than 90 percent. Among injectable drug users, it reduces risk by 70 percent.

What is PrEP for HIV?

PrEP (pre-exposure prophylaxis) is a combination of two antiviral medicines in one pill that you take every day. Continued use ensures there is enough of the medication in your bloodstream to block HIV from infecting you when you come in contact with it.

PrEP is appropriate for patients who are HIV-negative but have specific risk factors:

Gay/bisexual men

The HIV prevention pill is recommended for gay or bisexual men who have:

  • A partner who is HIV-positive
  • Non-monogamous relationships plus anal sex without a condom or a recently diagnosed sexually transmitted infection

Heterosexual men or women

Heterosexual men and women may benefit from taking PrEP if they have:

  • An HIV-positive partner
  • Multiple partners or a partner who has multiple partners and unprotected intercourse with injectable drug users or bisexual men

Drug use

Injectable drug users, or those who have used injectable drugs within the past six months, may benefit from PrEP, especially if they:

  • Share needles
  • Have participated in a treatment program recently
  • Have the HIV risk factors associated with sex

A Health Care Provider Must Prescribe the HIV Prevention Pill

If you have any of the risk factors for contracting HIV, talk with your health care provider about PrEP. At the initial visit your provider will test for:

  • Pre-existing HIV
  • Kidney function

If your test results are acceptable, you can begin taking PrEP. Plan to make follow-up appointments for every three months to receive refills and have repeat HIV tests.

There have been no life-threatening side effects reported, but some people taking PrEP experience mild side effects such as nausea or loss of appetite. If side effects don’t subside, you should discuss them with your provider at your next visit.

In some instances, your doctor may decide PrEP is not safe for you to continue taking. Otherwise, you should continue taking the HIV prevention pill every day until your risk of contracting HIV decreases. The effectiveness of PrEP increases when you combine it with other prevention methods, such as condoms.

To learn more about PrEP, the HIV prevention pill, contact your UCLA Health provider. The UCLA Center for Clinical AIDS Research and Education (CARE) offers HIV- and AIDS-related care. Use our ask an expert form to have questions answered by an HIV prevention specialist. You can also call 310-557-9062 to learn more about CARE or our clinical trials in HIV prevention.