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PEP (Post-Exposure Prophylaxis Against HIV) 

What is PEP (Post-exposure Prophylaxis)?

PEP is a method of post-exposure prevention to reduce the risk of acquiring HIV. These are some examples in which PEP is suitable for you:

  1. Torn condom

  2. Unsafe sex

  3. Under the influence of alcohol or drugs which may have caused loss of inhibition or cannot remember clearly the incident

  4. Rape cases

  5. Needle prick injury

  6. Blood contact through wounds

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How does PEP (post-exposure prophylaxis) work?

PEP has been a new treatment and there has been very successful to prevent HIV after an unlucky incident as above. PEP is basically three drugs that can be used to prevent and treat HIV. This combination is set with two NRTI (nucleoside reverse transcriptase inhibitor) and Integrase Inhibitors, when you think about it logically treatment for HIV is also the method which can be used to prevent HIV post-exposure.

HIV requires a host which is the human T-helper lymphocyte (human immune cell). Once infected, HIV requires multiple steps to breed. First step HIV needs to enter the Human T-helper lymphocyte. HIV has a protein called Integrase (to integrate) and its’ function is like a key to the T-helper lymphocyte door.

NRTI (Nucleoside Reverse Transcriptase Inhibitor) drug is to prevent HIV from replicating and multiplying while Integrase Inhibitor is designed to block the action of integrase, a viral enzyme that inserts the viral genome into the DNA of the host cell, therefore via this method a high-risk post-exposure of HIV becomes possible to prevent through blocking the pathways of HIV infection.

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How to start or initiate PEP (post-exposure prophylaxis)?

Unlike most medications; PEP needs to be started correctly and promptly and these are a few rules to adhere to:

  1. Starting PEP within 72 hours of the last high-risk exposure (unsafe sex, rape, needle prick injury, blood contact through the wound). 

  2. Medical history (Allergy, Medication, Prior experience with PEP, Drug abuses, Other STD, Infections like Hepatitis B / Hepatitis C / Gonorrhea / Syphilis)

  3. Important history about the event and other sexual encounters to identify possible HIV naïve during the “Window Period”

  4. To ONLY STARTED IN HIV NEGATIVE patients who are tested NEGATIVE. (You are possibly infected with HIV however the patient remains negative for HIV because of the “Window Period”.

  5. Perform an in-house HIV test if laboratory machines are available in the clinic or HIV Rapid Test with a 4th Generation Test for HIV or at least a 3rd Generation Test for HIV and to confirm that the patient is HIV Negative.

  6. The doctor must address the side effects of PEP based on the medications available to the doctor’s practice as each medication has different side effects.

  7. Medications once started must be taken daily and timely.

  8. Discuss follow-up and keep in touch with the patient for any side effects. Side effects are usually manageable and we will talk more about PEP side effects.


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How effective is PEP (post-exposure prophylaxis)?

PEP is not guaranteed to totally provide absolute 100% protection, nothing is 100%. The earlier you get started; you may have better your efficacy. In retrospective clinical studies, we have seen the great benefit of PEP.

You need to understand that PEP is not only for gay men as the study is done on all gay men but it is for anyone with potentially high-risk exposure or behaviour.  As gay men are at higher risk of acquiring HIV, therefore, the study is performed on the gay population. PEP is effective from eighty-six to ninety-seven per cent against the risk of HIV. In conclusion, if PEP is effective for gay men who are at higher risk of acquiring HIV; then other lower-risk populations like heterosexuals, lesbians, and transexuals should possibly receive higher protection while on PEP after any high-risk exposure. 

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What is the side effects of PEP (post-exposure prophylaxis)?

Patients will always ask me about side effects and the drug damaging effects of liver and kidney. My response will always be “Do you eat fast food?” and my patients will say “Of course!”. “Well do you know that eating food can increase cholesterol or certain foods consumed are cancerogenic? So why do you still eat them?” This usually stops my patient for a while to reflect on the logic behind their own actions. Take this analogy: You eat fast foods and your cholesterol may increase. Is cholesterol increment considered a side effect of eating fast food? Well, Yes!

My argument here is; anything you consume into your body can possibly be bad for health but the important fact is that we have to monitor and detect the side effects early. Everything is bounded by Newton’s First Law: For every action, there is an opposite reaction.

Side effects may range differently from one person to another:

  1. Abdominal symptoms: Nausea, Dizziness, Abdominal Bloating, Loose stool

  2. Insomnia but not in all people on PEP

  3. Allergies

  4. Lethargy

Most of these symptoms are considered “Start-up Syndrome” when started on PEP during the 1st week of PEP commencement and tend to resolve spontaneously by the 2nd week.















Other side effects may include liver and kidney derangement or damage. In a study conducted: PEP has shown to cause some derangement of liver and kidney function but patients spontaneously recover after stopping PEP. Some people may have some pre-existing liver and kidney diseases which were not diagnosed before therefore PEP may cause damage to these organs. In a study conducted PEP is considered short-term for 28 days and has not reported any liver or kidney failure or permanent damage. Safety is well established for PEP but if you have any doubts; you can always talk to your doctor about your side effects and we can help you.


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What should you do while on PEP (post-exposure prophylaxis)?

HIV prevention PEP is invaluable for the reduction of HIV infectivity, medical financial burden if infected with HIV and psychological unease after a possible high-risk exposure. Therefore efforts need to be made for more and more people to be aware of the existence of PEP.

There are some rules to observe when you are PEP:

  1. Take your medication time as prescribed. Same time and same dose.

  2. Avoid unprotected sex for 3 months from the day you were started on PEP

  3. Inform your doctor about any unsafe sex (includes torn condom) while you are on PEP. You doctor may consider extending the PEP period for another 28 days from the last unsafe sex day.

  4. Avoid Grapefruit and Pomelo fruit or extracts of Grapefruit and Pomelo. These fruits block the action of an enzyme called cytochrome P-450 3A4 which can cause the drug to remain in the body longer and unable to clear, thus leading to accumulation of the drug at higher levels.


  5. While on PEP until 3 months from the last high-risk exposure there are some situations that need immediate attention. For example:

  6. If ejaculated into the vagina. A partner needs to consider the morning-after pill to prevent conception and consider for the partner to be started on PEP.

  7. If ejaculated into anus or mouth. A partner should be started on PEP.

  8. If ejaculated on a wound or broken skin. PEP may be considered. However, if ejaculated on intact skin then wash off and not needed to start on PEP.

  9. Accidents can always happen and in some cases, your blood from injuries sustained can come in contact with another person with a wound. There is a possibility of HIV transmission but there have not been any reported cases where HIV has been passed through this mode. Kindly discuss with your doctor who is providing you with PEP and if your doctor is unsure then he should always discuss with an Infection Disease Specialist.


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Why is it important to go for follow-up after PEP (post-exposure prophylaxis)?

Yes. PEP does not guarantee that you will not get infected by other STDs like Hepatitis A, Hepatitis B, Hepatitis C, Syphilis, Gonorrhea and other sexually transmitted diseases.

Before starting on PEP we need to screen if the patient has HIV, Hepatitis A, B, C or syphilis and other STDs as a baseline. This baseline is used to be sure that the patient is negative for other STDs. Why is the baseline is important? It is important because the baseline shows a timeline of the patient’s sexual history. Take for example that the patient was tested for Syphilis during the baseline (before the commencement of PEP); this shows that the patient was already be infected by other high-risk contacts prior to the most recent high-risk contact which warrants PEP. Then treatment against syphilis and other STDs are required to be initiated as soon as possible.

The initial testing before starting on PEP is to determine pre-existing diseases like Hepatitis A, B or C and syphilis. After completion of PEP, your doctor should recheck if you have been infected with other STDs which can be transmitted during the high-risk contact which warrants PEP.

This concludes the information about PEP and may you have more knowledge at this point in time than when you first started reading this article. For any enquiries call us, email us or book an appointment with us via our website.

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