Post-exposure prophylaxis or post-exposure prevention (PEP) of HIV infection is any preventive medical treatment started immediately after exposure to the virus in order to prevent the development of disease.

PEP is a course of antiretroviral drugs which reduces the risk of seroconversion after events with high risk of exposure to potentially HIV-infected body fluids (e.g., unprotected anal or vaginal sex, needlestick injuries or sharing needles). Factors that can increase the possibility of HIV infection include condom tears, the presence of blood eg. menses, cuts, ulcers and being uncircumcised. The CDC recommends PEP for any HIV-negative person who has recently been exposed to HIV for any reason.

Clinics use different PEP regimens (antiretroviral drug combinations) based on a patient's specific circumstances. Although different regimens may be employed, they all have to be taken for one month.

To be most effective, treatment should begin within an hour of exposure. After 72 hours post-exposure PEP is much less effective, and may not be effective at all. Prophylactic treatment for HIV typically lasts four weeks.

While there is compelling data to suggest that PEP after HIV exposure is effective, there have been cases where it has failed. Failure has often been attributed to the delay in receiving treatment (greater than 72 hours post-exposure), the level of exposure, duration of treatment (lack of adherence to the 28 day regimen), or all three. However, given that, for non-occupational exposures, the time and level of exposure are based on patient-supplied information, absolute data is unavailable. The standard antibody window period begins after the last day of PEP treatment. Doctors will advise patients who received PEP to get an antibody test at 6 months post-exposure as well as the standard 3 month test.

The antiretroviral regimen used in PEP is the same as the standard highly active antiretroviral therapy used to treat AIDS. It requires close compliance and can have unpleasant side effects including malaise, fatigue, diarrhea, headache, nausea and vomiting.

Fortunately, the newer PEP regimens very rarely cause adverse effects. Fewer than 1:100 patients experience nausea, diarrhoea and lassitude. Rash and fever are seen in less than 0.1%. Antiretroviral drugs affect liver and kidney function so these need to be monitored.

HIV PEP Post Exposure Prophylaxis

HIV PEP Post Exposure Prophylaxis

The costs involved are:

  • Consultation - $60-80, depending on the duration
  • Blood tests (Full Blood Count, liver & kidney function tests) - $140, to establish a baseline; no need to wait for the results to start PEP; not required if done recently, eg. during a health screening
  • Rapid HIV test - $50, to ascertain that the patient does not already have an established HIV infection
  • Medication - $1800 for the entire month, regardless of which regime is used

The total cost is around $2200, less if blood tests are not required.

Original, branded antiretroviral drugs are available at the larger hospital pharmacies at NUH, SGH or CDC (TTSH) and certain GP clinics like Drs. Tan & Partners[1] and Dr. Chua at Cambridge Clinic. The cost of Truvada at these places is over $900.

Much cheaper generic versions (around 1/4 the price of the branded original) may be obtained through buyers' clubs modelled after Dallas Buyers' Club, as seen in the movie. There are several of these clubs in Singapore. One of them is organised by Rev. Yap Kim Hao of the Free Community Church which has a closeted cell group of HIV-positive churchgoers. A seperate club which supplies generic antiretroviral drugs to people living with HIV is headed by Arthur who may be contacted via his handphone, number 97531592. Arthur sells generics at one of the cheapest prices available. He disclosed the fact on Blowing Wind, a forum accessible to anyone in the world even without registration, that he has been on antiretroviral medication since 2002 and that his viral load is undetectable. It is to give people living with HIV hope that one can lead a normal life with antiretroviral therapy. However, one needs to show him a doctor's prescription before one can buy the drugs.

The Ministry of Health and Health Science Authority tacitly allow these buyers clubs to source for generic anti-retroviral medication from overseas and have them shipped to the Action for AIDS (AfA) headquarters along Kelantan Lane, just opposite the Department of STI Control. From these stocks, representatives of the clubs can then procure the drugs for sale to individual buyers.

AfA may be contacted via their hotline: 6254 0212.

Some Singaporeans also travel to Bangkok, Thailand to buy the generics and to be followed up by the STI specialists there once every three months. Many catch a flight on Friday evening and return to Singapore by Sunday night. Places where generic antiretrovirals may be obtained include Bumrungrad Hospital, the Christian Bangkok Hospital and the Thai Red Cross AIDS Research Center. The latter is colloquially referred to as the "snake farm" or "Sa Pa Ka Chad" in Thai. It is located along Angreedunang Road, at the junction opposite Surawong Road. The Thai Red Cross is reputed to offer the cheapest prices. However, one has to factor in the cost of airfare, accommodation, food and local transport. Another physician which also prescibes and sells generic antiretrovirals is Dr. Natthakhet of Sathorn International Clinic, tel/fax: +66 (0) 20093877, e-mail: He used to work at the Thai Red Cross. Opening hours are 1700 to 2000hrs on weekdays and 0800 to around 1800 or 1900hrs on weekends. Many Singaporeans who are wary of the large crowds at the Thai Red Cross consult him.

Caring Pharmacy in Malaysia also stocks antiretroviral drugs. Dr. Singaraveloo of Johor Specilaist Hospital, 39 B Jalan Abdul Samad, tel: 02-07 225 3000 ext. 4854 is a physician who sees HIV-related problems.

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This article was written by Roy Tan.