Dr. Tan and Partners is one of the few approved Anonymous HIV Testing Centres in Singapore. A detailed write up on our service is available here.

Other STD services: Early STD Screening, Rapid Hepatitis B Blood Test, Swab for Gonorrhea and many more... contact us to make an appointment now!

There is NO CURE for HIV EXCEPT…

Within 72 hours of any POTENTIAL EXPOSURE to HIV, you can prevent a HIV infection by taking a course of medications known as PEP.

These are tablets that if taken within 72 hours of any POTENTIAL EXPOSURE to HIV, will SIGNIFICANTLY REDUCE (up to 99%) the chance of HIV infection.

There is unfortunately NO WAY to conclusively know within 72 hours if you have HIV.

So if you are NOT SURE, DO NOT TAKE THE RISK. There is NO CURE for HIV.

See our doctor and decide if PEP could save your life.

Click here for more Info on PEP at Our Clinics including Prices

PEP International Expert Opinion

The WHO defines Post-exposure prophylaxis (PEP) as:

a short-term antiretroviral treatment to reduce the likelihood of HIV infection after potential exposure, either occupationally or through sexual intercourse.

Quotes from the Joint WHO/ILO Guidelines on Post-Exposure Prophylaxis to Prevent HIV Infection:

‘In sexual exposure, the potential for HIV transmission arises if a condom was not used, broke or came off.’

With regards to oral sex, ‘the risk may increase if the exposed individual has the significant oral disease, and HIV PEP may be offered in such cases.’

‘When there is a risk of HIV transmission, post-exposure prophylaxis should be initiated as soon as possible, within hours and no later than 72 hours following the potential exposure.’

‘Initiating PEP within 12, 24 or 36 hours of exposure is more effective than initiating it 48 or 72 hours following exposure.’

HIV PEP (Post-Exposure Prophylaxis) FAQ

What is PEP?

PEP stands for Post-Exposure Prophylaxis.

It is a regime of medication given to a patient after he/she has been exposed to HIV. It can potentially prevent the onset of HIV/AIDS. It is the only chance we have of ‘curing’ HIV.

Who should take the PEP?

PEP medicines are prescribed to anyone who has had a high-risk exposure to HIV. This includes the exposure of the vagina, rectum, eye, mouth or other mucous membranes or non-intact skin with the blood, semen, vaginal secretions, rectal secretions, breast milk or any bodily fluid that is visibly contaminated with blood of a person known to be infected with HIV. If the HIV status of the partner is unknown, decision to start PEP is made on a case-by-case basis depending on the risk assessment. This will be determined by our doctor after a thorough interview.

When should PEP be started?

PEP must be started as soon as possible after exposure. The earlier PEP is started, the more effective it is.

PEP must be started within 72 hours after exposure.

How is PEP started?

You will first see our doctor and undergo a thorough interview and examination to determine if you are a candidate for PEP.

Once we have decided on PEP treatment, you will first undergo a rapid HIV test to determine your HIV status. Patients who are HIV positive will NOT be given PEP.

We will then draw blood and urine to test for all other STDs, Complete Blood Count, Liver Function Tests and Kidney Function Tests.

You will then be prescribed the PEP medications which you will take for 1 month. You MUST complete the course of medication.

When can I be sure that I do not have HIV?

You must be followed up for 3 months after PEP treatment.

Click here for more Info on When to test for HIV during and after PEP

You will be required to undergo HIV testing during your initial visit, 1 month and 3 months after starting PEP.

You must come back earlier for evaluation if you experience a combination of any of the following symptoms that might suggest a HIV infection:

  1. Fever
  2. Enlarged Lymph Glands
  3. Rash
  4. Body aches, Joint aches
  5. Diarrhoea
  6. Headache
  7. Nausea and Vomiting
  8. Weight Loss

What other follow up do I need to do?

We will also need to monitor your Liver Function, Kidney Function and Blood Count during your follow-up visits.

On case-by-case basis, we might also need to repeat tests for other STDs.

Click here to see the full range of our HIV/STD Services

What if I also have other STDs?

If any of our tests show any other STDs, you will be given appropriate std treatment in Singapore and follow-up. This will not affect your PEP treatment.

Need more advice?

Come down to Our Clinics for a discussion with Our Doctors, or call our clinics for more information:

Email: hello@dtapclinic.com.sg


  1. Luin chan

    Hi Dr , i was given a PEP made up of the following drugs within 48 hours , my worry is will these three drugs works ,
    Tenofovir DF ,atazanavir/ ritonavir .

    was this correct . I a bit worried . Im on day 17 while taking this PEP

    • Dr. Julian Ng


      This is not the recommended PEP regimen by CDC. However check back with your doctor who gave you the PEP.

  2. Dear Doc,

    15 days ago I had protective sex three times in one night with a HIV+ man, he is under medication for the last two years, we deep kissed he had no blisters or wounds in the mouth, and during that time, he fingered me twice,

    I had no wounds in my miss V.
    Might I have contracted the HIV virus from fingering and kissing?

    I started PEP treatment at the 55th hour after exposure.
    I’m so anxious to know my status. Can I go for a test today?
    Please advice.

    • I would say your initial risk is already quite low. And the fact that you are on PEP would reduce this risk to almost zero. Doing a test today would not be of much use though.

  3. Hi Doctor,I realise today a 4th generation test while i am on pep,stiil have another 13 days of tablets!Do u think that a negative result after 15 of exposure,with 4th generation test can be conclusive?Please answer

    • It is not conclusive at this point. Please repeat one after completion of PEP.

      • 19 days after exposure my HIV test, 4th generation, is negative. I’m still on PEP for another 8days. Is this a good indication?

  4. Anonymous

    Hi Doctor,
    I went to another clinic due to urgency for a PEP. That doctor did not screen me other other STDs even upon request. Report came back with just full blood count, liver, kidney functions and body fats.
    Once after my PEP, I would like to go to your clinic at the 3month mark for screening.
    Would like to know how much is it roughly about.

  5. Nervous John

    Hi Dr Tan,
    I french kissed and had both unprotected oral sex (cunnilingus & fellatio) & protected intercourse with the same sex worker on 21 Dec 2013 & 17 Jan 2014. I have no sex history before, these are my 1st & 2nd times. For the pass few weeks I’ve been having umbilical pain. Could that be a STD inflected symptoms? When can I perform both STD & HIV tests?

    • Nervous John

      I just started to have sore throat today, will that be related to STD transmitted through cunnilingus?

    • Hi, you are obviously at risk of HIV and all other STDs. You should see a doctor to further assess your symptoms. Generally speaking, HIV and STD test can be performed at 1 month post exposure. However you should get your symptoms attended to first.

  6. hye dr tan,
    is it autoimmune disorder like diabetes can prolonged the hiv window period from 3 mths to 6 mths.is it 3 mths antibody screening is conclusive for the patient who was diabetes.

    • Is Diabetes an auto-immune problem? You mean type 1 DM? I think what you mean is Diabetes can compromise the immune system. I am however not aware of any evidence that Diabetes can affect the HIV window period. Please post any follow up questions on http://www.askdrtan.com

  7. Foreigner to China

    I had unprotected sex with a girl at a massage parlour in china. I ejaculated inside of her, pulled out and washed the excess semen and liquid off my head. I asked my friend to ask this girl if she had any diseases and she said no but i am just not convinced eventhough it was an upmarket massage parlour. This incident happened 18th January 2013, today is the 22nd. I am depressed and scared, my mind is not at ease and i feel like killing myself.

    I know that this was a very stupid and irresponsible move from my part and i regret it. I would do anything to take this back as the guilt i felt aferwards cannot be described. I am a safe individual and i only have one sexual partner, my girlfriend. I have gone for my routine hiv/aids test and the results have been negative always. I can’t stop thinking about it and i keep reading blogs, forums and stats and i have convinced myself that i have hiv/aids. My questions are:

    1) what is the minimum window period time to wait before going for an accurate hiv/aids test? I just need to know because this will affect my relationship and my life.
    2) i keep reading that its difficult for a man to get hiv/aids from a woman, what are the chances?
    3) i have this tingling and pinching feeling in my lower abdomen, testicles and penis head? Could this be a sign of an std?
    4) is there any std prevention meds i can take right now?
    5) can i take P.E.P?

    Support and advise is highly appreciated.

    • 1. 10 days RNA PCR. 2. 0.1%. 3. Yes but not HIV. 4. Yes but I cannot prescribe. Please see your doctor. 5. You are passed the 72 hours window for PEP. However in certain cases we will still prescribe it. Another thing to see your doctor about.

  8. Hi Doctor,

    i have isentress and combiver for my PEP after 60 hours exposure. Is it too late to start PEP? Accroding to your experience, are there any pep failure? I am really anxious, since i can make sure the guy who is positive.

    • I am very disappointed that this was not discussed with you by the doctor who gave you the PEP. As far as I know, the cut off for commencing PEP is 72 hours and the success rates vary from 80% to 87%. I have personally seen PEP failure. Please see your doctor for more advice.

  9. hi dr tan a pleasant day last august 2012 i had a contact with a lady and sadly the protection broke im so worried,i am a seafarer so theres no chance for me to get tested but luckily i was able to get tested using HIV testing kit after an hour it doesnt shows im positive but when i return after 4 hours the result came with 2 stripes meaning positive now my question is what should be the time limit to base the accuracy of result??thank you and more power

    • I cannot comment on this as I do not know what kit you used. Read the instructions. If you are still unclear, see a doctor for a HIV test when you can. Please post any follow up questions on http://www.askdrtan.com

  10. I had sex with a lady i meet in a pub,the condom i was using bust we wet for an hiv test and she test postive,i in pep is their a chance for me to negative after 6 months

    • You really should have had a careful discussion on the efficacy of PEP even BEFORE starting on the treatment. It is pointless to be discussing this now. Please see the doctor who dispensed the medication to you for more advice.

  11. charliebrown

    Had a HIV 1/11 test after 6 months exposure and it was non reactive. Is it a confirmation that I don’t have HIV?

  12. jack tan

    hi Dr

    i really need your advice, i dont know whether she have hiv or not, but will the percentage gets higher because of her period and blood contact straight to my penis? is getting PEP adviceable? i have se with her around 40 hrs ago.

    • If you think you need PEP the right thing to do is to see a doctor. NOT post questions on the Internet.

  13. jack tan

    hi DR

    need your advise urgently just came back from phuket and have sex without condom with a sex worker. and half way her period came. that happens 36hrs ago. how can i contact you?

  14. Dr. I had unprotected oral sex with a male. Since then I had no fever, but a rash on my face, vomiting, diahrea, a swollen lymph node in my left armpit. I also had a severely sore throat which I have been seeing a ENT for. He has advised me that he think it is my lingual tonsils that are cronically swollen or infected. I tested negative for HIV using fingerprick test at 4 weeks. How accurate is that at 4 weeks?

  15. Dr tan, i was drunk yesterday, went into a massage house, and end up having sex with the therapist,
    I used a condom thou, is there any chance for me to be infected if let say she is hiv +? i really worry about this… Thanks

    • Hi Chris,

      Condoms are 85% protective against HIV. That should answer your question.


      Dr Tan

  16. Dear dr
    I had sex worker last 72 hours precisely ladyboy with artificial vagina. It wa mostly oral and I had much to drink therefore I couldn’t perform. Next day when I got erection I inserted into her vagina for barely few mins and ejaculated outside. However I’m getting frequent urination and slight itching. I do have previous prostatitis condition for past 3 years cuz I’m single and do not engage sexually on regular basis. Could I be at risk of HIV? I went to a doctor and gave me PEP I just took one pill and not sure to continue cuz side effects are alot. Could u please advice ? I started ciprobay 500 my regular medicine to control the urine.

    • Before that I didn’t have intercourse for 8 months and I did Elissa test and other STD all came out negative.

    • Hi sameer,

      There is no use to take only one day of pep. You either complete the course or not take it at all. You need to find out what is causing your urinary frequency and itching. Not all stds can be cured by cipro.


      Dr tan

    • Hi Sameer,

      I cannot recall if I have answered your question or not. It is really pointless to take PEP for 1 day. You either complete the course or not start at all. You have actually done yourself a huge disfavor. If you really have been infected with HIV, not only do you NOT enjoy the benefits of protection from PEP, you have risked developing drug resistance to the medicine you took. You really need to find out what is causing your urinary frequency and itching. It sounds like urethritis. Ciprobay might not be the correct treatment depending on what infection you have. You will need to monitor your HIV status closely for the next 3 months.


      Dr Tan

  17. Hello Dr Tan,

    Had an unprotected sex with sex worker before an year.
    Had an ELISA (hiv i and ii) test at 12th month and Anti HIV i & ii (MELA)and p24 test at 15th month. All tests were negative.

    A) Are above results conclusive, can i stop worrying on this and stop further testing.
    B) i am having bronchitis for couple of years, does this impact the test results.

    Kindly advice.

    • Hi Sharon,

      Yes the tests are conclusive. You can stop testing and stop worrying. Bronchitis will not affect the accuracy of the tests.


      Dr Tan

  18. Dr tan, i’ve had my tooth extracted on 2days ago and i had some foreplay with a sex worker today with no sex or oral sex involve. only exposure is my tongue and lips on the nipples. i have no idea what to make of this. the tooth socket have no healed.

    • Hi joel,

      Are you afraid of getting infected with HIV from her breast milk? Unless she was actively lactating at the time, this is highly highly improbable. In fact, I would go so far as to say it is impossible to catch HIV from this exposure, even with your raw tooth socket.


      Dr Tan

  19. Hi Dr Tan,
    I am currently working overseas. I visited a sex worker last night and while having sexual intercourse, my condom (the top part) broke and it wasnt until few minutes after that i realized it. It was the first time such thing happened and i am totally freaked out now.

    what are my chances of getting infected? is it advisable for me to do PEP (becos the country i am in now doesnt have, i would have to fly back today)

    pls help..thanks

    • Hi dav,

      Advising on PEP is complicated and really must be done via a face-to-face consultation. There are many details that have to be considered. First of all we need to consider the risk of the sex worker having HIV. Second we need to consider the risk of transmission. In your case if it is just unprotected (condom broke) insertive vaginal sex then we are looking at a risk of between 0.1% and 0.01%. You have to balance these risks against the cost and potential side effects of PEP. As I said, this is a very complicated discussion that has to be done face-to-face. I will be in my clinic at Robertson Walk on Monday should you wish to see me. That is still within the 72 hours window.


      Dr Tan

      • thanks dr tan for your prompt reply. u have been really helpful.

        the sex worker said that she has tested negative on 5th nov. though it doesnt mean that shes disease free, it lowers the probability of her being a carrier and i am really hoping she isnt. besides i have read up terrible side effects of PEP and have decided not to go for it.

        instead, i will plan for a trip back to singapore to do check up at the earliest date. when would you advise me to do so? i read from your site that the earliest is pcr but the results take two weeks. i am thinking of doing the instant p24 combo test and a test on the STDs 28 days later. I only know of the window for hiv but not for std. would the tests done(hiv and std test) be conclusive for my status of hiv and std 28 days later?

        thanks doc

        • Hi dav,

          28 days post exposure is the perfect time to screen for HIV and all the other STDs.


          Dr Tan

          • Dr tan,
            My penis forehead top layer skin is peeling off. Theres no itch or blood. I am not sure ifbthis is something to worry about (std possibility) as I did not notice thisnbefore.

            Should I fly back earlier for a diagnosis? Really worried. Ols advise

          • Hi Dav,

            It is really difficult for me to make a diagnosis without actually conducting a physical examination. Your symptoms however do not sound like a typical STD. It sounds more like a fungal infection or just a dermatitis (allergy to latex?) But again it is impossible to make a diagnosis this way and you really cannot rely on this post as proper medical advice. Why don’t you see a dermatologist in whichever country you’re in?


            Dr Tan

  20. Hi Dr.Tan,

    I have taken ELISA test (only HIV test) one year after exposure, the results were negative.

    My questions and worry are
    Have seen an article that antibodies would not be produced if a person has chronic disease.

    – I have a skin problem around 4 years and dermatologist has identified it as mild form of parapsorasis and have been taking external medications like ketaconazole shampoo and candid-b lotion for scalp and few ointments for skin like propysalic. And have long back taken UVB light treatment.

    Would like to know if any above factors would have resulted in not producing enough antibodies to be detected during elisa test.

    Kindly advice,

    • Hi Sam,

      Your fears are unfounded. Antibody production will not be affected in your condition. I am sure you do not have HIV.


      Dr Tan

      • Thanks Dr.Tan. It gave me peace of mind.

        Many many thanks for your great and wonderful service.