This guideline is going to be for GUM, rather than us, but as I hadn’t heard of this concept, I thought it worth explaining as it may become relevant in the future or you may have patients using it. It basically involves patients who are at higher risk of HIV infection (eg serodiscordant couples, or men who have sex with men) using some kind of drug as prophylaxis against HIV. Both tablets and vaginal gels have been tested.
Currently it is far less effective than condoms, or treatment of an HIV positive partner, so is not advised. However you may have patients who are on it as part of a trial.