HIV pre-exposure prophylaxis (PrEP) is the regular use of antiretroviral medication by HIV-negative individuals to prevent HIV infection
Currently, PrEP refers to prophylactic daily oral use of tenofovir disoproxil fumarate/emtricitabine (TDF/FTC), a formulation that is indicated in Canada for the treatment of HIV infection. Although licensed only in the United States for PrEP, this formulation is used off label in Canada for carefully selected and monitored individuals who are at high risk of HIV infection, based on expert clinician judgment. Those at high risk include men who have sex with men and who have frequent unprotected anal intercourse.
PrEP is efficacious in the prevention of HIV, with adherence being the critical determinant of effectiveness
Randomized controlled trials of PrEP have found reductions of 44%-75% in HIV incidence among men who have sex with men, heterosexual people and people using injection drugs. (1-4) Pharmacodynamic modeling suggests efficacy above 99% if PrEP is taken daily. (5) A trial of intermittent dosing, as well as...