Last reviewed: 16 September 2026
PrEP stands for pre-exposure prophylaxis. It is HIV prevention medication used by people who do not have HIV and who may have an ongoing chance of acquiring HIV.
When used as prescribed, PrEP is highly effective at preventing HIV. It should be used under medical supervision as part of an individual HIV prevention plan.
PrEP may be appropriate for adults and adolescents without HIV who may be exposed to HIV through sex or injection drug use.
Whether PrEP is appropriate depends on individual circumstances. A healthcare professional can assess your HIV status, medical history, possible exposures and the PrEP options available in your country.
PrEP should not be started without confirming that the person does not have HIV, because using certain PrEP medicines in someone with undiagnosed HIV can contribute to drug resistance.
PrEP is highly effective at preventing HIV when it is used correctly and consistently. Its effectiveness depends on using the prescribed regimen as directed.
PrEP reduces the chance of acquiring HIV, but it does not protect against other sexually transmitted infections (STIs) or prevent pregnancy.
Different PrEP methods are available internationally. These include oral antiretroviral medication and long-acting prevention options.
The exact medicines approved or recommended for PrEP vary by country, population and individual medical circumstances. For this reason, the most appropriate PrEP regimen should be selected together with a qualified healthcare professional.
European HIV prevention guidance includes oral tenofovir-based PrEP as an established prevention option, while international guidance also includes newer long-acting PrEP methods.
Yes. HIV testing is an essential part of PrEP care. HIV-negative status should be confirmed before PrEP is started, and regular HIV testing is required while PrEP is being used.
Follow-up appointments may also include checks for other STIs and, depending on the PrEP medicine and the individual, monitoring of kidney function or other health parameters.
The exact monitoring schedule should be determined by the healthcare professional prescribing PrEP.
PrEP is generally well tolerated, but side effects can occur. The type and frequency of side effects depend on the specific medicine.
Some people using oral PrEP experience temporary effects such as nausea, headache, tiredness or stomach discomfort. Certain oral PrEP medicines can also affect kidney function in some people, which is one reason medical follow-up may be recommended.
People using injectable PrEP may experience reactions at the injection site. Always discuss persistent, severe or concerning symptoms with a healthcare professional.
PrEP and PEP both use HIV prevention medicines, but they are used at different times.
PEP must be started as soon as possible and no later than 72 hours after a possible exposure. If a recent exposure occurred, seek urgent medical advice rather than waiting to start PrEP.
Drug resistance is uncommon when PrEP is used correctly by someone who does not have HIV. The main concern arises when PrEP is started or continued during an unrecognised HIV infection.
This is why HIV testing before starting PrEP and regular testing during PrEP use are important parts of safe PrEP care.
PrEP is one of several HIV prevention options. Depending on individual circumstances, prevention may also include condoms, regular HIV and STI testing, sterile injecting equipment and other measures.
If you are considering PrEP, speak with a healthcare professional or sexual health service about whether it is suitable for you and which options are available where you live.
