PrEP and DoxyPEP are both strategies to help prevent sexually transmitted infections, but they work very differently and protect against different things.
PrEP, which stands for pre-exposure prophylaxis, is medication taken regularly to prevent HIV infection. It usually involves taking a daily pill that contains antiviral drugs such as tenofovir and emtricitabine (known as Truvada or Descovy), or receiving a long-acting injection like cabotegravir (Apretude). When taken correctly and consistently, PrEP reduces the risk of getting HIV by more than 99%. It doesn’t protect against other sexually transmitted infections like syphilis, gonorrhea, or chlamydia — its focus is HIV prevention.
DoxyPEP, which stands for doxycycline post-exposure prophylaxis, is a newer approach designed to prevent bacterial STIs, not HIV. It involves taking a single 200 mg dose of the antibiotic doxycycline within about 72 hours after having sex. Studies show it can significantly reduce the risk of getting bacterial infections like syphilis, chlamydia, and, to a lesser extent, gonorrhea. However, it doesn’t prevent HIV, and because it’s an antibiotic, there are concerns about side effects and the potential for antibiotic resistance if used frequently.
In short, PrEP prevents HIV and is taken before exposure, while DoxyPEP prevents bacterial STIs and is taken after exposure. Some people at high risk use both together — PrEP to protect against HIV, and DoxyPEP to reduce the risk of other STIs — under the guidance of a healthcare provider.