Q and A


Should I keep a few pills in case I need PEP again in the future?

Is it a good idea to stop PEP on Day 26 and keep the 2 remaining Truvada and 4 raltegravir pills as “insurance” in case of a future mishap?

I ask because after a condom break and unverifiable HIV status of my sex partner, obtaining PEP was a miserable experience due to emergency room staffing shortages and my travelling.

Most of the stress was in this phase and should I ever need it again, I would like to be able to start within minutes, not after 28 hours. If not advisable, are there starter packs that can be obtained? I know all the stuff about liver testing and verifying HIV before treatment, but if I test negative and only have safe sex, the latter is pointless.

The liver testing could be done after a couple days I’m imagining (anyway, few side effects besides a bit of tiredness) Thanks for a practical answer.



Thanks, yes, the short answer is that there are lots of reasons why this might be a good idea and very few reasons not to consider this.

A slightly longer response continues…

There is actually very little data on the effectiveness of PEP. This is mainly because HIV is already such a difficult virus to catch, any study would need to include many thousands of PEP cases to start to see anything significant. So even though some PEP studies report low numbers of infections – often none – these studies usually only include a few hundred people when looking for something that might only have a 1 in 500 chance of occurring anyway.

The study I remember that showed a benefit used starter packs – and this has always made the most sense – especially if someone is at higher risk.

i-Base information always stresses the earlier PEP is started, the better chance it will work. This should ideally be within hours. On this basis, PEP clinics (including general hospitals) would be better to give someone a single Truvada tablet as soon as they walk through the door..

The single pill would start working immediately (FTC is absorbed very fast, tenofovir takes longer). This means PEP could start working while other tests are carried out. In the event that someone might already HIV positive, another med could be given to minimise any risk of drug resistance (ie switching to a boosted PI for two days). Another alternative would be an option to continue HIV treatment, which is increasingly an option on diagnosis.

There is no data to show there is any difference between 26 day or 28 days of PEP, so you can easily do this with little likely impact on the efficacy of PEP. Actually, there is no data showing a difference between 21 and 28 days either – I think 28 days was chosen for practical reasons as much as anything else.

In practice, after a needlestick risk. most health workers report stopping PEP within a week or two. This shows that even people who should be the best informed about PEP, often do not complete the full course. The full course is always recommended. 

Either way, holding back a few days of PEP does makes practical sense, especially when health services generally – certainly in the UK – keep people waiting for at least four hours, if not considerably longer. It would also take the uregency and panic out of getting PEP. so that if the incident happened at a difficult time, you could go to the PEP clinic the next morning.

You are right to be cautious about not using PEP in the future if you might become positive. You could explain all this to the clinic when you next need PEP.

There is little risk form a single dose of Truvada

An important caveat is that advocates at i-Base are not doctors. This practical information is just based on the theoretical mechanism for PEP and the difficulties in accessing PEP promptly.

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  1. Simon Collins

    Hi Abigale, please take the PEP as your hospital recommended. This is usually for 28 days.

  2. Abigale

    My partner is HIV positive but during our sex the condom break and I went to hospital the very same day to get pep pills. today it’s day 26 can I stop taking the pills?

  3. Lisa Thorley

    Hi Jack,

    From what you’ve said, it sounds like you need to see a doctor, you could be having some side effects to the ARVs, however there could be another issue. PEP needs to be taken for 28 days.

  4. Jack

    Hi there! Thank you for this wonderful website and your time answering our questions.
    I had a question about PEP, its side effects and discontinuation of the medicine. It is the weekend now and my doctor is not picking up her phone (so I will probably have to wait till Monday to reach her).
    I am now taking PEP for 20 days (Combivir + Kaletra (I am not based in the UK)). Besides an upset stomach which as I understand is a pretty common side-effect from taking Kaletra, I have been experiencing persistent dull pain (like a pressure) in the upper-left side of my stomach, dark urine and a weird smell when I wake up in the mornings (a smell of someone who is hungover). I am worried that these signs might indicate some kind of toxicity (liver or pancreas).
    In your original post you say that there is no scientific proof that there is a difference between taking PEP 21 days or taking it 28 days. I am currently debating if I should discontinue taking my meds now, since it has been 3 weeks already and I am worried what these meds might do to my body if I continue using them for one more week. Thank you!

  5. Roy Trevelion

    Hi Nkanelo,

    It’s good that your partner tested HIV negative. But it’s a good idea to check on the window period for his test. Most people will test antibody positive within 4 weeks of exposure. But 5% can take up to 3 months to produce antibodies to HIV.

  6. Nkanelo

    Hi,I just started PEP three days ago and i always feel sick.the reason i considered PEP was that the condom break and my partner refused to go and get tested with me.but today he got tested and the results are negative,so is it okay for me to stop taking PEP?

  7. Roy Trevelion

    Hi Nosipho,

    Have you finished your course of PEP? Some HIV meds used in PEP can cause a mild rash in the first week or so when you use it. But it’s a good idea to show the marks to your doctor so that you can ask what’s causing them.

    If you live in South Africa you can contact the Treatment Action Campaign for local support for HIV prevention. Here’s a link to their contact page.

  8. Nosipho

    After I used PEP i notice my body have some pimples left with black mark. Does this usually happen after you u’ve been using this treatment l

  9. Roy Trevelion

    Hi Cass,

    I’ve put your three comments in this one:

    It’s a good idea to talk to your doctor and ask these questions. Truvada, on its own, is not recommended as PEP.

    There are many variables that can increase or decrease risk, and this makes it difficult to answer these questions. It was one broken condom and your partner was on PEP. So it could be low risk.

    Talking to your doctor about your own health is important. And this is the best way to decide what you should do.

    Here’s a link to FAQs on HIV risks and HIV testing. I hope these pages will help to answer your questions.

  10. Cass

    Okay but can you further explain the topic of how you said that with the other person being on pep I have a small risk of infection? Again saying he has been on pep for about 4 days. And I have read that in the past truvada was the only prescribed medication for pep? What were the results then?

    But could truvada by itself be enough as a pep treatment?
    And can you further explain how my partner being on pep for 4 days can reduce the chance of receiving hiv from him?

    Are my comments going thru?


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