Prep pills, or pre-exposure prophylaxis, are medications taken to prevent getting HIV from sex or injection drug use. There are two pills approved for use as PrEP: Truvada® and Descovy® . Truvada® is for people at risk through sex or injection drug use, while Descovy® is for people at risk through sex. Apretude is the only shot approved for use as PrEP and is for people at risk through sex who weigh at least 77 pounds (35 kg) . PrEP is highly effective for preventing HIV when taken as prescribed. It reduces the risk of getting HIV from sex by about 99% and reduces the risk of getting HIV from injection drug use by at least 74% . PrEP is safe, but some people experience side effects like diarrhea, nausea, headache, fatigue, and stomach pain. These side effects usually go away over time. PrEP does not protect against other sexually transmitted infections, so condom use is still important for protection against other STDs.