Does the idea of taking a pill instead of using a condom appeal to you? There’s a lot of talk about two new medical technologies for HIV prevention, both before and after exposure: pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP).

It may sound appealing, but there are a few things you should know: it may be difficult to access, it’s not one pill, it’s not guaranteed to work, and it offers less protection than sex with condoms for HIV, and no protection for other sexually transmitted infections. If you’ve had a high-risk exposure to HIV, PEP is an option available to you. PrEP, on the other hand, is still in research phase. It has shown promising results in preventing HIV infections in exceptional circumstances.

PEP consists of a daily schedule of antiretroviral drugs for a month; drugs which are already used to treat people living with HIV. Antiretrovirals are only available by prescription, and both PEP and PrEP must be medically supervised. We’ll tell you why.

 Post-Exposure Prophylaxis (PEP)

PEP is given to a person who has been exposed to HIV within 72 hours after the exposure, although ideally within two hours. It usually consists of two or three different antiretrovirals taken for a period of 30 days, accompanied by regular HIV testing.

PEP is mostly used in Ontario for health care workers accidentally exposed to HIV and survivors of sexual assault. In recent years, PEP has also been used for other forms of exposure, such as consensual unprotected sex, sharing needles, or for infants who have breast-fed from an HIV-positive mother. In Quebec, PEP has been offered since 1999 for sexual exposure with costs covered by the provincial health benefits plan.

Things to keep in mind:

• Cost: The price of a PEP regimen can range anywhere from $500 to $1200 in Ontario, even if you access it from a hospital emergency room. It might not be covered under your drug plan.
• Side effects: Antiretrovirals can cause intense side effects, which cause 35% of people who start PEP to not finish. PEP can also pose problems if you are on other medications or hormones, or if you have a liver or kidney condition. Let your health care provider know your medical information if you are trying to access PEP.
• Adherence: If PEP isn’t taken as prescribed, an HIV infection may develop with drug resistance, which makes it more difficult to treat the infection.
• Effectiveness: Prevention is not guaranteed. Both animal studies and experience with humans have shown that PEP is not always successful in preventing HIV infection, even if it is started right away.
• Access: PEP is not easy to get. Even where it is available, there are inconsistencies in who is given access to it. Not all emergency rooms or doctors have PEP. Some will only give you a prescription for PEP and no starter kit, and some might refuse it to you because they don’t consider your exposure as high-risk.

 Pre-Exposure Prophylaxis (PrEP)

When this resource was written, only one research study had been published demonstrating somewhat successful results in taking antiretrovirals before exposure to prevent HIV. In this study, PrEP cut the risk of HIV infection by an average of 43% in gay men and trans women. It should be noted that the people in this study were taking antiretroviral medications every day just like someone with HIV. The study showed that if they took less than 90% of the medication, PrEP was less effective. There are currently no data to suggest taking one or two doses of antiretroviral medications before sex will provide any protection against HIV.

It has been reported that some HIV-negative gay men are already using antiretrovirals to prevent infection before exposure. A survey published in 2009 said that this isn’t really widespread in Ontario.

Things to keep in mind:

• PrEP is still only in the research stages. As of writing, it’s not approved for use in Canada.
• If PrEP does become available, your health care provider would need to be involved. Without medical supervision, it could actually cause you more harm.
• PrEP is still an antiretroviral regimen: The same considerations apply for PrEP as PEP, including access, cost, side effects, adherence and effectiveness.

Post-Exposure Prophylaxis (PEP)
Plain and simple fact sheets for treatment after exposure to HIV)

Post-Exposure HIV Chemoprophylaxis (PEP) - A Discussion Paper, AIDS Committee of Toronto

The world of Post-Exposure Prophylaxis (PEP)
Prevention in focus, can we prevent infection with HIV after an exposure?

Pre-exposure prophylaxis (PrEP) - Plain and simple fact sheets

Preparing for Pre-Exposure Prophylaxis (PrEP) - Prevention in focus