Whilst not a cure specific to HIV, post-exposure prophylaxis (PEP) refers to any treatment that works to prevent a disease, rather than cure it. Within the context of HIV/AIDS, PEP refers to what is usually a four week course of highly active antiretroviral medication that is said to dramatically increase the development of HIV transmission after events with a high risk of exposure (unprotected sex, sharing needles etc). To increase its effectiveness, it must be taken as soon as possible after the event, with this being no more than 72 hrs after the likely transmission. Almost all major emergency rooms/hospitals in Western countries carry PEP for HIV exposure.
On a more personal level, I can say that the side effects are shocking, so reliance on this sort of preventative medication should be used only in an emergency. They range from diarrhoea, nausea, vomitting, nose bleeds, lethargy with many other less common effects experienced. This is made even worse by the fact that PEP is not even assured of working so there is also the chance you are taking it for nothing (or for that matter, you may have never even contracted it in the first place - it typically takes at least 6 weeks for a confirmed positive test from a particle swab)

).
Still though, the choice for me (Mr. Candyslut) was a no brainer. No need to risk your life. Literally. It certainly gave me a new appreciation for people who live daily with these symptoms.