PEP – A Way to Prevent HIV Infection after Exposure

By Adam, April 8th, 2015 in

Post Exposure Prophylaxis (PEP) involves taking a combination of two to three types of anti-HIV (antiretroviral) drugs less than 72 hours after a possible exposure, as a way to reduce the risk of HIV infection. The drugs must be taken for 28 days. The medication must be taken exactly how the doctor prescribes. The sooner the drugs are taken, the more likely the drugs will work.

Exactly how the drugs work depends on the specific regimen the doctor prescribes, but essentially, the medication aims to prevent HIV from using your cells to make copies (more HIV). This is particularly important when considering how quickly you must start treatment. If HIV is given the time to make too many copies, and spread throughout the body, PEP will not work. If medication is started too late, or is not taken correctly, the risk of HIV infection increases. If a person becomes infected with HIV while taking PEP, their HIV may become resistant to the PEP drugs, meaning the same anti-HIV drugs may not work for treating their HIV.

Although studies show a lot of promise in post exposure prophylaxis’s ability to drastically reduce the likelihood of HIV infection when taken correctly, it is still not 100% effective. There are many documented cases of individuals testing positive while taking PEP.

PEP is not to be used by a person living with HIV. An HIV negative person may consider taking PEP if they’ve had a possible exposure in the last 72 hours. In order to receive treatment a person must first discuss their situation with a nurse, doctor or counsellor, and test negative for HIV. Not all possible exposures contribute to the same risk of infection; for example the risk of HIV infection is much lower with oral sex than it is with anal sex. If the likelihood of HIV transmission is low, PEP may not be recommended. PEP is not to be used as a primary prevention method. It should be used for emergencies only, as it does not prevent against pregnancy or other STIs. PEP may also be hard on the body; if side effects and toxicity are a problem, a doctor may decide to change one or more of the anti-HIV drugs being used for PEP.

Exposure is classified into two categories: occupational exposure and non-occupational exposure. Occupational exposure refers to a possible exposure that happens at the workplace (for example, a healthcare worker who accidently suffers a needle-stick injury.) It is likely that this type of exposure will result in your workplace’s health insurance or workers’ compensation covering the cost of the anti-HIV drugs. Non-occupational exposure refers to an exposure that did not happen at the work place (for example, a condom breaking during sex). If you are prescribed PEP after sexual assault, you may qualify for partial or total reimbursement. Anti-HIV drugs are expensive: a month-long course of PEP can cost more than $1,000. If you cannot get insurance coverage, private, or employer-based, your healthcare provider may be able to help you apply for assistance. Please note: Many healthcare providers are unaware of non-occupational PEP, are not trained to provide PEP, or may be unwilling to prescribe it.


Trillium Health Partners Sexual Assault/Domestic Violence Services:

  • Provides the entire 28 day regimen of HIV PEP (and the necessary medical follow up) to survivors of sexual assault at risk of HIV exposure

Trillium Health Centers:

  • You will be triaged
  • The emergency department has HIV PEP 5 day “starter kits” available to people who are at risk due to potential exposure
  • There is no cost associated with the 5 day “starter kits”, but additional cost are associated with any prescription that is needed to filled out for the full treatment

Brampton Civic Hospital- William Osler:

  • You will be triaged, and seen by the ED physician who will order the prophylaxis after an assessment
  • They will provide the first dose in a pre-pack kit and then give a prescription for you to fill in the out-patient setting

If you have the means to do so, you should consider St Michael’s Hospital located at 30 Bond St, Toronto, ON. They are said to have PEP knowledgeable doctors and the most progressive non-occupational PEP assessment program in Ontario, including much shorter waiting times and a large HIV clinic. To read one person’s experience with taking PEP and accessing services though St Michael’s visit: (note: graphic language, graphic content)

To read more about PEP visit:

Written by:
Arron Maynard  – Men’s Health Promotion Coordinator


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