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PEP: Post-Exposure Prophylaxis (Treatment after exposure to HIV)

(Finalized March, 2005)

What is PEP?

“Prophylaxis” means taking some medications to prevent disease.
“Post-exposure prophylaxis” (PEP) means taking anti-HIV medications soon after exposure to HIV to prevent infection.
PEP involves taking 2-3 different kinds of anti-HIV medications from different classes for a period of one month.
PEP is not a cure for HIV/AIDS. It is also not 100% effective. Different studies have estimated that PEP may prevent between 80%–90% of HIV infections.

When should PEP be given?

PEP should be started as soon as possible after exposure to HIV. Ideally, PEP should be started within 24 hours, and certainly within 72 hours, of exposure to HIV.

Who may consider PEP?

1. Work-related exposure: Most commonly, PEP has been given to health care workers exposed to HIV from needle-stick injuries.
2. Other exposure: PEP may also be considered in other situations of known exposure to HIV, such as unprotected sex and sharing needles with a partner known to be HIV positive, especially when the situations are unexpected or involuntary (for example, in cases of rape or when the condom breaks accidentally).

Concerns about the use of PEP outside work settings:

Many policy makers and health care providers have expressed concerns about using PEP for non-work-related exposure situations. These include the following:

1. PEP is not like the “morning after pill” that prevents pregnancy. It is a much more complicated regimen that involves several drugs that need to be taken several times a day, for at least 30 days.
2. The medications in PEP may cause many unpleasant side effects.
3. PEP is very expensive. One month of PEP usually cost around $1,000. It is not a cost-effective way to prevent HIV infection.
4. Unsafe behaviours that led to HIV exposure outside of work settings may occur many times, (e.g. unprotected sex or sharing needles) and it is not possible to start PEP every time a person engages in an unsafe behaviour.
5. If people think that PEP is an easy way to avoid HIV infection, it may encourage them to continue unsafe behaviours. PEP should not replace practicing safer sex with condoms and using clean, unshared equipment for drug use as ways to prevent HIV infection.

What are the other risks of PEP?

1. Each of the medications used in PEP has side effects, such as fatigue, nausea or diarrhea.
2. If you have been exposed to a strain of HIV that is resistant to some anti-HIV medications, then it is possible that PEP may not work for you.
3. If you do not take the PEP medications regularly as prescribed, you may develop HIV infection.

Where can I get PEP?

Policy and practices of providing PEP may vary in different cities. The important thing to remember is that PEP should be started as soon as possible after exposure to HIV, ideally within 24 hours.
Contact your doctor or health service provider immediately if you find out that you have just been exposed to HIV. If you cannot reach them within 24 hours, contact your local sexual health clinic or emergency department for advice.