Emergency HIV prevention requires accurate and readily accessible information. “PEP” or Post-Exposure Prophylaxis is a highly effective antiretroviral treatment when initiated immediately after potential exposure.
This article will provide you with a comprehensive understanding of PEP, covering its mechanism of action, usage guidelines, duration, cost, side effects, and service locations. It also addresses common questions to help you make informed decisions when facing unexpected situations.
PEP (Post-Exposure Prophylaxis) is an antiretroviral medication for emergency situations, used to reduce the chance of HIV infection after a risk event such as having unprotected sex, condom breakage/slippage, sexual assault, or injury from a needle stick. This medication is a “post-exposure” measure, not a treatment for the disease, and it does not replace primary prevention methods such as condoms or PrEP, which are more suitable for long-term prevention. Recipients should be assessed by a doctor for suitability and must take the medication continuously as prescribed in order to achieve effective protection.
PEP inhibits the life cycle of HIV from the very early stage after the virus enters the body. The medication, usually a combination of 2–3 drugs, often includes NRTIs and/or Integrase Inhibitors, which block the enzymes the virus uses to create DNA and insert it into the genetic material of human cells. When the virus is unable to replicate and establish itself, the risk of infection is significantly reduced.
The standard course is 28 consecutive days. It should be taken at approximately the same time every day to maintain stable drug levels. Stopping the medication on your own or not completing the full course may reduce its effectiveness in prevention.
Missing doses causes the level of antiretroviral drugs to be insufficient to suppress the HIV cycle, significantly reducing protection and allowing the virus a chance to establish itself. If multiple doses are missed or skipped for a long period, you should inform your doctor for appropriate evaluation and management.
Common symptoms during the first 1–2 weeks include nausea, stomach pain, dizziness, fatigue, insomnia, or headache, which usually improve as the body adjusts. However, symptoms should be monitored; if severe or persistent, consult your doctor. PEP may also affect liver or kidney function in some cases, so blood tests are often performed as appropriate.
It may be considered in some cases when the “benefits outweigh the risks.” Doctors will select regimens with established safety data and monitor liver/kidney function as well as maternal and infant health as appropriate. Do not start or stop PEP on your own.
Yes, under the supervision of a specialist doctor. The dosage and regimen are adjusted according to age and body weight. If a child or adolescent has a risk event, they should be taken for evaluation and initiation within 72 hours.
Always use condoms. If a new risk occurs during the course, inform your doctor to assess whether the existing course is sufficient or if an additional plan is needed. Do not increase the dose or restart PEP on your own without consulting a doctor.
PEP reduces the chance of infection but does not always produce a negative test. If infection occurs, it may take several weeks before tests can detect markers. Normally, doctors schedule follow-up tests after the course, such as around 1 month and 3 months, to confirm results.
4 steps to receiving PEP (things to know before starting):
If convenient at Safe Clinic: Provides confidential consultations, has an in-house laboratory for rapid results within about 40 minutes before doctor consultation and treatment planning (service availability may vary by branch).
Generally, follow-up testing is done about 1 month after completing the course and again at around 3 months. Doctors may choose the appropriate testing method, such as Antigen/Antibody or HIV RNA, at their discretion. You should attend appointments even if you have no symptoms.
Costs vary by facility and regimen. Typical ranges:
Some public health agencies and non-profit organizations provide free or subsidized services for target groups. Common examples include the Anonymous Clinic of the Thai Red Cross and some public hospitals, as well as programs under the Department of Disease Control. Conditions may differ, so check before visiting.
In general, PEP is available at Emergency Rooms (ERs) of large hospitals open 24/7, such as university/major hospitals, as well as private hospitals with emergency departments. It is recommended to call ahead to confirm PEP service availability and the presence of relevant on-duty physicians.
No. PEP must be prescribed under medical supervision. Assessment and testing are required before starting to ensure the correct regimen and dosage, reduce risks of side effects or drug interactions, and establish a monitoring plan.
Many reported initial anxiety after risk events. Access to clear information and structured services helped them decide quickly. Mild side effects in the first week often improved, and the experience led many to adopt safer practices. Key lessons: “Act quickly, consult a doctor, and complete the course.”
Note: Services and availability may differ by branch. Please check before visiting.
Within 72 hours after a risk event. The sooner it starts (especially within 24 hours), the more effective it is.
Yes, if started late, doses are missed, or the regimen is inappropriate. Strict adherence to medical advice improves the chance of success.
No. It only prevents HIV. Condoms should be used to protect against other STDs.
Not necessarily, but condoms should always be used to reduce repeated risk and prevent other infections.
PEP is an emergency measure to reduce the risk of HIV infection after exposure. The key points are to start as soon as possible within 72 hours, complete the 28-day course, and attend follow-up appointments, while consistently using primary prevention methods. If unsure, consult a doctor immediately.
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