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Video on HIV Post Exposure Prophylaxis PEP

What is HIV Post Exposure Prophylaxis (PEP)?

PEP are medicines given to a person after a high risk HIV exposure to minimize the risk of him/her getting infected with HIV.

Common high risk HIV exposure scenarios include having unprotected sex with a casual partner or sex worker, or condom breaks or slips.

PEP has to be started within 72 hours after the exposure. It is up to 99% effective in preventing a HIV infection.

Most people tolerate the treatment very well although some develop side effects like nausea, diarrhea and lethargy.

Remember, PEP is only effective within 72 hours after a person has been
exposed to HIV.

Speak to our doctors if you suspect that you have had any high risk exposure to HIV.

Find out more about HIV related health information


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  1. hello doctor, is it true that pep is 99% effective and is there any pep failure in your experience?

    • It depends on which studies you read. Different studies differ in risk and medicines used. So it is very difficult to quote a blanket efficacy rate for PEP as a whole. In general, a figure of between 80% to 90% efficacy is usually quoted. I know there are some studies that quote 99% but this is not usual. Of course I have seen PEP failures. The fact is if a doctor has seen enough HIV cases and given out enough PEP, he must have seen PEP failures. I wrote about a case of PEP failure in my blog. Click HERE.

      • thanks you for the information doctor..so there has not been a failure after that case?
        Why do you think that case fail doctor and any other pep failure within 72 hours?
        thanks you in advance!

        • The fact is PEP is NOT 100% effective. There is no point in asking what my experience is. There is a chance of PEP failure is everyone. That is a fact. What my experience is does not change anything.

          • Sorry If i sound prying doctor, the reason i ask is bcuz i am on pep and ease my worrying mind by knowing successful pep

          • That is exactly my point. How would my experience in any way affect how successful PEP will be for you? If you ask a very junior Doctor who has only seen 1 case of PEP and it was a success then his experience is PEP is 100% effective. If you ask a very experienced Doctor who has seen thousands of cases of PEP, he would definitely have come across some cases of failure. How does this affect your chances? It does not.

  2. May I know estimated successful pep case in drtannpartner clinic and pep failure with the reason pleae?
    I just want to encourage myself from knowing the success pep and stop this depression while on pep.

    • Dr Justin Sim

      Don’t panic, PEP is very effective and you have taken the safest course of action to be on PEP. Just test at the right time after completing PEP and then we can be sure.

      • thanks for the reply doctor ..is it true that there are no pep failure with this new drug regime ?

  3. Worried student

    Dear Doctors,

    Please don’t delete my question, I have no idea why my question got deleted, I really need your advice, please……

    On 21 Jun 2015 (yesterday) I met a man with unknown status. Assumes he is HIV positive. His precum and cum came into contact with my old wound on my sole. He rubbed his penis against my sole and later cum on it. The wound was not bleeding or oozing blood at the time it came into contact with his precum/cum anyway.

    I got the wound on my sole on 15 Jun 2015, one week ago before my sexual encounter. I accidentally stepped on a sharp edge of a swimming pool, that’s how I got the cut. It was a small cut. At the time I was hurt, the cut would ooze blood if I press the wound hard. If I don’t press the wound it wouldn’t even ooze blood. Now one week after that, I am not sure whether the wound has healed or not when the precum and cum contacted with it.

    Doctor, is my case considered risky? Should I come to see you right away? Considering that PEP is only effectively within 72 hours after exposure, Tuesday is the last chance I shall take PEP. Will you suggest PEP?

    Best wishes and many thanks!
    Worried student