Post Exposure Prophylaxis (PEP) and Pre-Exposure Prophylaxis (PrEP) are two ways of using traditional HIV medication to prevent getting HIV.
PEP is Antiretroviral Therapy (ART) that is taken after an instance in which someone maybe have been vulnerable to acquiring HIV. The medication can be taken up to 72 hours after potential infection but has more efficacy the sooner you take it. The medication works in the same way that ART meds work for someone who is HIV positive but as the virus is so new to the body the medication is able to fight it off completely.
You can get PEP from GPs, sexual health clinics and A and E, though it is given at the health professionals discretion.
PrEP, again, is ART taken as HIV prevention. This is HIV medication that is taken by someone who is HIV-negative to prevent them acquiring HIV. Most commonly, this is one pill a day that is taken consistently. It is more efficient the more consistent the individual is at taking it. It is extremely good at preventing HIV infection. Unfortunately, PrEP is not available on the NHS in England currently. However, it can be bought online through I Want PrEP Now .