PEP Treatment in Chennai: Post Exposure Prophylaxis for HIV

Written and medically reviewed by Dr Shah Dupesh, MBBS, DCE, FASM · Consultant Andrologist
First published 15 October 2019 · Last reviewed and updated 27 September 2026

Hello! Vanakkam and Namaste & Welcome to Dr. Shah’s Clinic. This is Dr. Shah
Dupesh, consultant sexology doctor in Chennai.

If you are reading this at 2am after a condom broke, I know exactly how you feel. I see
that face in my consulting room every week.

So let me be your doctor for the next ten minutes. I will tell you what PEP is, how fast
you need it, which tablets we use, how well it works, and what the 28 days really look like.
Short answers first. Detail after.

That is the triage I run on the phone. Hours since exposure, and what kind of exposure.
Everything else follows from those two answers.

1. What is PEP treatment?

PEP stands for Post-Exposure Prophylaxis. It is a short course of anti-retroviral
medicines that reduces the chance of an HIV infection taking hold after a risky exposure.

Those exposures are usually one of four things. Sex without a condom, or with a condom that
broke or slipped. A needle-stick or blood splash at work. Shared needles. Sexual assault.

PEP is an emergency treatment. Think of it like a fire extinguisher. Brilliant when the
fire is small and fresh. Useless once the house has burnt down.

What PEP actually does inside your body

When HIV enters the body, it does not become a permanent infection instantly. It spends
the first hours and days trying to reach immune cells, copy itself and settle in for good.

PEP floods your blood with drugs that block that copying step. If the virus cannot copy
itself, it cannot establish itself. It simply fails. That is the picture at the top of this
page.

That is why timing is everything. PEP can only stop a process that has not finished yet.

The evidence for this is old and solid. Animal studies from the 1990s onwards showed that
PEP started soon after exposure prevented infection that otherwise always happened. A
meta-analysis of 25 of those studies found the risk of infection was 89% lower with PEP
(Irvine, 2015).

What PEP is not

• It is not a cure. If HIV has already established itself, PEP does not remove it.
• It is not a morning-after pill. It is a supervised 28-day course, started only
  after a consultation and an assessment of your exposure.
• It is not a substitute for condoms or PrEP. It is the safety net for when those
  fail.
• It does not cover other STDs. Gonorrhoea, chlamydia and syphilis need their own
  tests. More on that in section 17.

2. How soon to start PEP: every hour counts

PEP treatment for HIV works best when the medications are taken in the first 24 hours or
better yet at the ‘earliest possible time after a potential exposure’. When given
at the right time frame, pep treatment has been found to be 80% effective.

That 80% figure comes from the one human study that could ever be done on this. Health
workers who took zidovudine after a needle-stick had about 81% lower odds of infection than
those who did not (Cardo, 1997). Nobody will ever run a placebo trial of PEP in humans. It
would be unethical.

Today’s three-drug regimens are far stronger than the single drug in that
study.

The current CDC guidance is blunt about it. Give the first dose as soon as possible, ideally
within 24 hours, and no later than 72 hours after exposure (Tanner, 2025).

The first 2 hours

This is the gold window. If you call me within 2 hours, I want you started the same
afternoon. A modelling study found that a two-drug course may already protect poorly when
started more than an hour after exposure, which is one reason we use three drugs
(Zhang, 2025).

2 to 24 hours

Still very good. In monkeys, tenofovir started 24 hours after the virus protected every
single animal (Tsai, 1998). Most of my patients land here. They slept on it, panicked in the
morning, then called.

24 to 72 hours

PEP is still worth starting, but it is a race now. When the same monkey study pushed the
start to 48 or 72 hours, protection dropped (Tsai, 1998). In a vaginal-exposure model,
animals started at 12 and 36 hours were protected, while the 72-hour group had a breakthrough
infection (Otten, 2000).

So if you are at hour 60, do not waste hour 61 reading. Go.

Here is the practical rule I give every patient. Count the hours from the exposure, not
from when you started worrying. And do not wait for a working day. Call us the moment you
decide, so we are ready for you when you walk in.

3. Past 72 hours? Here is what I do instead

If it has been four or five days, PEP is off the table. By then the virus, if it got in,
has already settled. The medicines have nothing left to prevent.

That is not the end of the plan. It changes the plan.

Step 1: Do not buy PEP anyway

I meet patients who got a late course from somewhere just to feel they did something.
It adds side effects and no protection. Worse, it can blur the timing of your tests.

Step 2: Test at the right time, not the next morning

A test the day after an exposure tells you about the months before, not about last week.
The useful test depends on how many days have passed. I explain
when an HIV test becomes reliable on a separate page, so you
are not tempted to test too early and misread a negative.

Step 3: Check for everything else

An exposure risky enough for HIV is risky enough for gonorrhoea, chlamydia, syphilis and
hepatitis B. Those are testable, and most are curable. Section 17 covers it.

Step 4: If it keeps happening, plan PrEP

If you find yourself here more than once, the answer is not a faster PEP. It is PrEP,
started before the next exposure. Section 16 explains the difference.

4. The PEP regimen: which tablets are used

The WHO recommended regimen for pep treatment is a drug combination of Tenofovir combined
with either lamivudine or emtricitabine as a preferred backbone drug.

You can read the current WHO guidelines for HIV post-exposure prophylaxis for
yourself. That backbone has not changed. The third drug has. Dolutegravir has replaced
ritonavir-boosted lopinavir as the preferred third drug. In a German trial, lopinavir
caused more nausea and diarrhoea than a darunavir-based alternative (Fätkenheuer, 2016).

All these drugs are routinely used in
HIV treatment protocols, which is why their safety is so
well understood.

The backbone: tenofovir with lamivudine or emtricitabine

Tenofovir is the anchor. In the animal meta-analysis, tenofovir-based PEP was linked with
better protection than other drugs (Irvine, 2015). In people, tenofovir-based courses were
also finished far more often than older zidovudine-based ones, 78.4% versus 58.8% (Ford, 2015).

The third drug: dolutegravir

Dolutegravir is an integrase inhibitor. It blocks the step where HIV inserts itself into
your cell’s DNA. In 100 men given dolutegravir with tenofovir-emtricitabine, 90%
completed the course and nobody acquired HIV (McAllister, 2017).

In India this comes as a single tablet called TLD: tenofovir, lamivudine and
dolutegravir together. It is the same first-line combination the national programme uses for
treatment (Deshwal, 2026). One tablet, once a day. That simplicity is a big reason people
finish.

Older regimens you may still see

Some pharmacies and some old prescriptions still carry lopinavir/ritonavir or
zidovudine-based PEP. They work, but the side effects drive people to stop early. If someone
hands you one of these in 2026, ask why.

The ones I see most often in India are the older single tablets that pair tenofovir and
lamivudine or emtricitabine with efavirenz. In my practice they cause far more nausea
and vomiting than dolutegravir, and the man who is vomiting on day 4 is the man who stops on
day 5. That is why I do not use them for PEP. The regimen that protects you is the one you can
finish.

Current CDC guidance lists bictegravir-based and dolutegravir-based regimens as preferred
for most adults (Tanner, 2025). I choose between them based on your kidneys, your other
medicines and what is in stock that day. Every hour counts more than the brand.

Why I will not tell you brand names

You will see brand names on search pages. I name the molecules on purpose. The brand does
not matter. The three molecules, the dose, and the 28 days do. And the right choice for you
needs a doctor looking at you, not a product page.

5. Is PEP treatment dangerous? Side effects, honestly

No. PEP is not dangerous for the vast majority of people. It is, however, not
side-effect free, and I would rather you hear that from me than panic on day three.

The newer drugs seem to have a better tolerance profile for patients. Common side effects
reported by patients while on PEP include

1. Nausea
2. Headache
3. Gastritis
4. And Fatigue

Most of these symptoms are transient in nature, and will spontaneously subside on their
own.

Here is what the numbers look like on a modern regimen.

Loose stools are also common. On a raltegravir-based course, nausea or vomiting affected
27%, diarrhoea 21% and headache 15%, all mild and self-limiting (Mayer, 2012). On the single
bictegravir tablet, nausea dropped to about 15% (Mayer, 2022).

How long the side effects last

Most settle within the first week or two as your body gets used to the tablets. The first
three to five days are usually the worst. That is when people are tempted to stop.
Do not.

How to make them easier

• Take the tablet with food, at the same time every day.
• Night-time dosing helps some people sleep through the nausea.
• Drink plenty of water.
• Keep antacids, calcium and iron tablets a few hours away from dolutegravir.
• If it is bad, call me. We adjust. We do not quit.

Kidneys and liver

Serious harm is rare. In the dolutegravir study, kidney filtration fell by an average of 14 units
over the 28 days, and dropped below the normal cut-off of 60 in 3% of men. A liver enzyme rose
in 22%, with no case of clinical hepatitis (McAllister, 2017). That is why I check your kidney and liver tests at the start.

Erections during the 28 days

Some men tell me their erections go off during the course. In my experience that is the
worry talking far more often than the tablets, and it settles once the tests come back clear.
If it does not, it is treatable; see my page on
erectile dysfunction treatment.

Allergic reactions

These are uncommon, but real. A 2026 case report described a hypersensitivity reaction
within an hour of starting bictegravir-based PEP, and a more severe drug reaction after
switching drugs, in a doctor with a prior sulfa allergy (Goel, 2026). Tell
me about every drug allergy you have. A rash, fever or swelling on PEP is a same-day call.

6. The 28-day PEP course: why every day matters

PEP is taken every day for 28 days. Not 20, not 21, not “until I feel safe”.
Current guidance is 28 days for both sexual and occupational exposures (Tanner, 2025;
Kuhar, 2013).

Why 28 days and not less

This number came from careful animal work. When tenofovir was started 24 hours after
exposure, 28 days protected every animal. Only half were protected with 10 days, and none with
3 days (Tsai, 1998).

So stopping early is not a small shortcut. It throws away the protection you have already
paid for with side effects.

28 days or 30 days?

Twenty-eight. Some bottles contain 30 tablets. The extra tablets are not an instruction.
Stop at 28 days unless I have told you otherwise.

How to take it

• One dose at the same time every day. Set a phone alarm.
• With food if it upsets your stomach.
• No alcohol binges. In my clinic, a heavy night out is the usual story behind a missed dose.
• No new sexual exposures during the course. Use condoms every time.

Current guidance also recommends a check-in within about 24 hours of starting, by phone or
in person (Tanner, 2025). I do this with every patient of our
sexual health clinic. It is where we
catch the day-two nausea before it turns into a stopped course.

7. PEP success rate: how effective is PEP, really?

PEP cut HIV risk by about 80% in the classic health-worker study (Cardo, 1997). Modern
regimens, started early and finished, do better. In 1,744 Los Angeles courses, about 1 in 100
people (17) still became positive (Beymer, 2017).

So PEP is highly effective, but it is not 100%. Anybody who promises you 100% is selling
something.

Here is what the evidence actually says, in plain numbers.

The human evidence: about 80%

In health workers exposed to HIV-positive blood, those who took zidovudine had odds of
infection about 0.19 times those who did not. That is roughly an 81% reduction
(Cardo, 1997). This is where the 80% figure comes from, and it was one drug, not today’s
three.

The animal evidence: 89%

Across 25 animal studies and 408 primates, PEP cut the risk of infection by 89%
(Irvine, 2015). Earlier starts and tenofovir-based regimens did best.

Modern three-drug PEP: over 90% in modelling

A 2025 modelling study found three-drug PEP could exceed 90% efficacy when started within
48 hours and taken for at least 14 to 28 days (Zhang, 2025). In real clinics using modern
regimens, infections during follow-up are rare. None occurred among 100 men on dolutegravir
(McAllister, 2017), or among 52 people on bictegravir (Mayer, 2022).

Why the number is not 100%

Because PEP is a race against time, and people do not always finish it. In the Los Angeles
series, 7 of the 17 who became positive reported a fresh exposure, and late starts and missed
doses were more common among them (Beymer, 2017). The next section takes each one in turn.

8. Why PEP fails: the five reasons I see

Interestingly, the scientific literature suggests that there are a few cases of patients
testing positive after PEP treatment. When I look at those cases, I look for what went
wrong, because it changes what we do next time.

The best data comes from Los Angeles. Of 1,744 PEP courses with follow-up testing, 17 people
became positive. Seven reported a fresh exposure after starting PEP. Those who became positive
were also more likely to have missed doses, started later in the 72-hour window, or used
methamphetamine (Beymer, 2017).

Four of the five are in your hands. Here they are.

1. Started late

The later in the 72 hours you start, the higher the risk (Beymer, 2017). Hour 70 is not
the same as hour 7.

2. Missed doses

PEP needs steady drug levels for 28 days. Gaps let the virus through. Section 9 has the
missed-dose rules.

3. Exposed again during the course

This is the one nobody talks about. PEP covers the exposure you came in for. It cannot
promise to cover a new one halfway through. In the Los Angeles data, 7 of the 17 who became
positive reported a fresh exposure after starting PEP (Beymer, 2017). Any new exposure also
deserves its own check at our STD clinic.

4. A drug-resistant virus

Rarely, the source partner carries a strain resistant to one of the drugs. This is uncommon
with dolutegravir-based regimens, but it is why I ask about the partner’s treatment
history whenever it is known.

5. Stopped early

Shorter courses protected fewer animals in the timing studies (Tsai, 1998). Feeling fine
on day 15 is not a reason to stop.

9. Missed a PEP dose? What to do, and why finishing matters

Life happens. You fell asleep, you were travelling, you forgot. Here is what to do.

If you remember the same day

Take it as soon as you remember. Then carry on at your usual time the next day.

If the next dose is almost due

Skip the missed one and take the next dose on time. Never double up. Two tablets
together do not make up for the gap. They only double the side effects.

If you have missed a full day or more

Call me the same day. We decide together whether to continue, and whether your testing plan
changes.

Now, why do I fuss about this so much? Because completion is the weak link of PEP
everywhere in the world.

How many people actually finish PEP

Across 97 studies and over 21,000 PEP courses, only 56.6% of people completed the full 28
days. After sexual assault it was just 40.2%, and after non-occupational exposures 65.6%
(Ford, 2014). That is not a drug failure. That
is a support failure.

Simpler regimens help. At one Boston community clinic, completion was only 39% on the
older zidovudine-based regimens (Mayer, 2017). It rose to 57% on twice-daily raltegravir
(Mayer, 2012), 71% on a once-daily single tablet (Mayer, 2017) and 90.4% on the bictegravir
tablet (Mayer, 2022). In Australia, 90% finished a dolutegravir
course (McAllister, 2017). Setting and support matter as much as the drug.

So my job is not only to prescribe the tablet. It is to make sure you still take it on day
21, when the fear has faded and the nausea has not.

10. Who needs PEP (and who does not)

PEP is decided by what happened, not by who you are. Your job, your marriage, your
sexuality: none of these make you a PEP candidate. The exposure does.

Current guidance recommends PEP when there has been a real exposure to blood or sexual
fluids through broken skin or a mucous membrane, and the source has HIV without sustained viral
suppression, or their status is unknown (Tanner, 2025).

Risk varies hugely by the type of act. Receptive anal sex carries the highest sexual risk,
estimated at 138 infections per 10,000 exposures. Oral sex is rated low risk in those
estimates (Patel, 2014). I use these numbers with you, not to scare you, but to decide
whether PEP is worth 28 days of tablets.

Oral sex and massage parlours: why I still give PEP

“It was only oral, doctor.” I hear this every week, very often after a massage
parlour visit. Low risk on paper is not no risk. Over the years I have seen a number of men
test HIV positive whose only reported exposure was orogenital contact. So after oral sex with
a partner whose status is unknown, including at a massage parlour, I offer PEP after
assessing the exposure, the same as I would after vaginal sex.

Travelling, and you think it may happen

Many of the men I see travel for work. Some tell me honestly, before the trip, that they
may be intimate with someone while they are away. I do not judge that. I would rather you
tell me than hide it. For these men, after a consultation and a risk assessment, I give PEP
as a safety fallback, so it can start within hours of an exposure instead of after a
panicked search for a doctor in a strange city. If trips like this are a regular part of
your life, PrEP is the better plan; section 16 explains it.

When the partner is on treatment and undetectable

If your partner has HIV, takes treatment and has had an undetectable viral load for at
least six months, they cannot pass HIV on through sex. PEP is not needed. Condoms plus a
partner on effective treatment cut the risk by 99.2% even in the older estimates
(Patel, 2014).

After sexual assault

Call us and come straight in. You will be assessed for PEP, emergency contraception where
relevant, hepatitis B vaccination and STD prevention, in a private room.

In one national sexual assault service, hepatitis B vaccination was started in over half of
cases (Kane, 2024). You will be treated with privacy and without questions you do not want
to answer.

Survivors say how they were spoken to shaped whether they finished PEP
(Porter, 2026). The medical part is only half of it, and
psychosexual counselling is there for the weeks
after.

Pregnancy and breastfeeding

Being pregnant or breastfeeding is not a reason to refuse PEP. Integrase-based regimens,
including dolutegravir, are used in pregnancy in current guidelines. Tell me, so we choose and
monitor the regimen properly.

The mistake I see most

People underestimate their own exposure. In a Brazilian cohort given ready access to PEP,
the commonest reasons for not starting it among those who later became positive were
“it was my steady partner” and “I did not think it was risky enough”
(Schechter, 2004). If you are unsure, call. That is literally what the call is for.

11. What happens when you come to the clinic for PEP

You will be in and out faster than you fear. A PEP visit, like every
confidential sexual health consultation
we run, goes like this, step by step.

The questions I ask

• How many hours since the exposure?
• What exactly happened: which act, condom or not, any bleeding?
• What do you know about the other person’s HIV status or treatment?
• Your kidney history, current medicines and drug allergies.

Nothing you tell me leaves the room. I have heard every version of this story, and none of
them shock me.

The baseline tests: compulsory before the first tablet

A rapid or fourth-generation HIV test before PEP is recommended (Tanner, 2025). In my
clinic, nobody gets PEP without four rapid tests first: HIV, hepatitis B, hepatitis C and
syphilis. There are no exceptions. I also check kidney and liver function, because
tenofovir is cleared by the kidneys.

The baseline HIV test is there to confirm you were negative before this exposure. It
cannot tell you anything about the exposure itself. The hepatitis and syphilis results tell
us what else needs treating or vaccinating, and they give us a clean starting point for your
follow-up tests.

The first dose does not wait for results

This matters. The first PEP dose should not be delayed for pending laboratory results
(Tanner, 2025). The four rapid tests give results within the same visit, so they do not cost
you hours. In the Los Angeles clinic, the first dose was not offered at the start of the
visit, and the authors recommended fast-track dosing precisely because timing predicted who
became positive (Beymer, 2017).

Why not just walk into a pharmacy?

PEP is a prescription medicine in India, and for good reason. It should be taken only
after a clinical consultation and an assessment of your exposure. Without the baseline test you
may start PEP when you are already positive, which is the wrong treatment. Without kidney
tests nobody knows whether tenofovir is safe for you. And without follow-up nobody catches the
day-three nausea that ends the course.

For the same reasons, do not buy PEP online. You lose hours to delivery, and hours are the
one thing you cannot spare.

12. HIV tests after PEP: the follow-up schedule

Finishing the tablets is not the finish line. The follow-up tests are.

Current guidance is testing at 4 to 6 weeks and again at 12 weeks after the
exposure (Tanner, 2025). For work-related exposures with a fourth-generation test, follow-up
may conclude at 4 months (Kuhar, 2013).

The confirmatory test I use: NAAT

For the confirmatory tests after PEP, I use NAAT (nucleic acid amplification
testing), not an antibody or rapid test alone. For HIV that means the HIV-1 & 2
qualitative PCR, which looks for the virus itself. In the same visit I run NAAT for
chlamydia and gonorrhoea too, because PEP does nothing against them and they are far
easier to catch than HIV.

Why PEP changes the timing

PEP can slow down how quickly a test turns positive if the infection has broken through. In
one documented case, one person who took 30 days of prophylaxis did not show antibodies
until 70 days after their blood donation (Nishiya, 2021). That is why, after a sexual or other non-work exposure, the 12-week
result, not the 6-week one, closes the question.

The general rules on test timing belong on a different page. If you want the full picture,
read my guide to the HIV window period. Here I will keep it to
the PEP schedule.

If a follow-up test is positive

It happens rarely, and it is not the end of anything. We confirm it with a second test, and
you move straight on to starting HIV treatment in Chennai
with the same doctor, the same week.

13. Where to get PEP treatment in Chennai

You have one good option, and one bad one.

The good option: our clinic in T Nagar

Call us on 97907 83856 and come in. We assess, test and
start you on PEP. The whole thing is confidential. No public register of why you came, no
awkward questions at reception, no queue of people who might know you.

Dr Shah’s Clinic, No 21, Sree Kalki Apartments, Ground Floor, Bazullah Road,
T-Nagar, Chennai 600017. Clinic hours: Monday to Sunday, 9am to 6pm.
Open the clinic in Google Maps.
Please call before you come, so we are ready for you.

Your privacy comes first

Most men who need PEP are more afraid of being seen than of the virus. I understand that.
Here your exposure is discussed with one doctor, in a closed room, and your tests and
tablets are handled by us. Nothing goes on a public record because you came for PEP.

The bad option: waiting

Waiting for Monday, waiting for a friend’s advice, waiting to see if you get
symptoms. There are no symptoms to wait for. The only thing waiting does is spend your
hours.

Because an exposure risky enough for PEP needs a look at other infections too, we run the
whole thing as a confidential STD clinic visit rather than a one-drug
prescription.

Coming from outside T Nagar?

Patients come to us from across Chennai: Adyar, Anna Nagar, Velachery, OMR, Tambaram and
Porur. Call before you set out, tell us the hours since the exposure, and we will be ready
for you when you arrive, so the drive does not cost you more time than it has to.

14. PEP treatment cost in Chennai

PEP is a one-time 28-day course, not a monthly bill. And it costs a tiny fraction of what
lifelong HIV care costs. Cost should never be the reason you wait.

The PEP cost in Chennai at our clinic has four parts.

Call 97907 83856 and I will tell you the exact total before you
come. No hidden extras, no surprise tests added at the counter.

Why the tablets are affordable

The medicines are generic and made in India. The single-tablet regimen is the same
combination the national programme uses for HIV treatment (Deshwal, 2026).

What drives the price up elsewhere

• Imported brand-name tablets instead of generics.
• Panels of tests you do not need, sold as a package.
• Repeat visits because nobody explained the plan the first time.

If you need PEP and cost is genuinely the barrier, tell me on the phone. We will find a
route. Nobody should skip PEP over money.

Dr Shah Dupesh

Consultant Andrologist & Sexologist

★★★★★800+ positive patient reviews

Private 1-on-1 consultation

Worried about an exposure? Call me today.

Confidential PEP assessment in T Nagar, Chennai, and your course started without delay. No judgement, no public register of why you came.

Book a Confidential Consultation

or call directly: +91 97907 83856

🔒 100% private🧪 12+ years in andrology💬 Honest, no-shame advice

15. PEP after a needle-stick injury or occupational exposure

Nurses, doctors, lab staff and housekeeping staff all get needle-sticks. Hospital
records show needle-sticks are common (Naidu, 2023), and a ten-year review from one tertiary
centre concluded they are under-reported (Perumal, 2024).

The average risk of HIV after a needle-stick from an HIV-positive source is about 0.3%.
Deep injuries, visible blood on the device and a needle that had been in a vein or artery all
raise it (Cardo, 1997).

First aid, straight away

1. Wash the wound with soap and running water.
2. Do not squeeze the wound, scrub it, or pour bleach on it.
3. Splash in the eyes, nose or mouth? Rinse with plenty of clean water.
4. Report it to your supervisor or infection-control team immediately.
5. Get assessed for PEP within hours, not at the end of your shift.

What happens next

Occupational exposures are urgent medical problems. The source patient’s HIV status
should be established where possible, and PEP, when indicated, uses three drugs for four
weeks (Kuhar, 2013). You are also checked for hepatitis B and hepatitis C. If you are not immune
to hepatitis B and the source may carry it, you get hepatitis B vaccine, hepatitis B
immunoglobulin (HBIG) or both, as soon as possible and within 1 to 7 days (Puro, 2005).

The outcome for health workers who complete PEP is excellent. In a 10-year hospital series,
none of the 444 who completed follow-up became infected with hepatitis B, hepatitis C, HIV or
syphilis (Lee, 2023). A 2026 review of 132 studies confirmed occupational HIV infection is now
rare (Marques-Medeiros, 2026).

If you are a health worker in Chennai and your hospital cannot start PEP quickly, call us.
Hepatitis B is a bigger risk than HIV after most needle-sticks. I cover it on my
hepatitis B treatment page.

16. PEP vs PrEP: which one do you need?

They sound alike. They do opposite jobs. PEP is the emergency brake after one exposure.
PrEP is a daily prevention tablet taken before exposures, for people with ongoing
risk.

If you have needed PEP more than once, you are the person PrEP was designed for.
Current guidance asks doctors to offer PrEP and a PEP-to-PrEP transition plan to anyone with
continuing risk (Tanner, 2025). Having used PEP was one of the main predictors of later
starting PrEP (Zhang, 2025).

I do this transition at the end of the 28 days, without a gap. I keep the PrEP detail
short here on purpose; the point is simply that it exists, and it works better than
repeated PEP.

17. PEP covers HIV only: test for the other STDs too

PEP does nothing against gonorrhoea, chlamydia, syphilis, herpes or hepatitis B. These
spread more easily than HIV. So an exposure that worried you about HIV deserves a full check
for them as well.

What I test for after an exposure

• Gonorrhoea and
  chlamydia: NAAT on urine and, where relevant,
  throat and rectal swabs. After oral sex the throat swab matters most.
• Syphilis: a blood test, repeated later.
• Hepatitis B and C: blood tests, plus hepatitis B vaccination if you are not immune.

The simplest way is a full STD check in one visit, timed so each test is meaningful.
Book it with us and I will stagger the tests correctly.

Doxy-PEP is a different thing

You may read about “doxy-PEP”. That is a single dose of the antibiotic
doxycycline after sex, studied to prevent bacterial STDs in high-risk groups
(Luetkemeyer, 2025). It does nothing against HIV and is not a substitute for HIV PEP.

18. PEP tablet uses in Tamil: PEP மாத்திரை பற்றி தமிழில்

Many of my patients search in Tamil, so here is the essential PEP information in Tamil.

PEP (Post-Exposure Prophylaxis) என்பது HIV தொற்று ஏற்படக்கூடிய ஒரு ஆபத்தான
தொடர்புக்குப் பிறகு எடுத்துக்கொள்ளும் அவசர தடுப்பு மாத்திரை ஆகும்.

PEP மாத்திரை எதற்குப் பயன்படுகிறது?

பாதுகாப்பற்ற உடலுறவு, ஆணுறை கிழிதல், ஊசி குத்துதல் (needle-stick) அல்லது பாலியல்
வன்முறைக்குப் பிறகு, HIV வைரஸ் உடலில் நிலைபெறுவதைத் தடுக்க PEP பயன்படுகிறது.

எப்போது தொடங்க வேண்டும்?

சம்பவம் நடந்த 72 மணி நேரத்திற்குள் தொடங்க வேண்டும். 2 மணி நேரத்திற்குள் தொடங்கினால்
மிகவும் நல்லது. ஒவ்வொரு மணி நேரமும் முக்கியம்.

எத்தனை நாட்கள் எடுக்க வேண்டும்?

தினமும் ஒரே நேரத்தில், 28 நாட்கள் தொடர்ந்து எடுக்க வேண்டும். இடையில்
நிறுத்தக்கூடாது.

பக்க விளைவுகள் என்ன?

குமட்டல், தலைவலி, சோர்வு, வயிற்றுப்போக்கு ஏற்படலாம். பெரும்பாலும் முதல் ஒன்று அல்லது
இரண்டு வாரங்களில் தானாகவே சரியாகிவிடும். உணவுடன் சாப்பிட்டால் குமட்டல் குறையும்.

முக்கிய எச்சரிக்கை: “Pep” என்ற பெயரில் வரும் மற்ற மாத்திரைகள் (உதா: Pep-40, D-Pep)

“Pep” என்று பெயர் தொடங்கும் சில மாத்திரைகள் அசிடிட்டி (வயிற்று எரிச்சல்)
அல்லது மூட்டு வலிக்கானவை. அவை HIV PEP அல்ல. HIV PEP மருத்துவர் பரிந்துரை இல்லாமல்
கிடைக்காது.

உடனே எங்களை அழைக்கவும்: 97907 83856. உங்கள்
விவரங்கள் முழுவதும் ரகசியமாக வைக்கப்படும்.

In short, for my Tamil-speaking readers: PEP is an emergency HIV-prevention tablet, started
within 72 hours and taken for 28 days. The acidity tablets with “Pep” in their name
are completely different medicines. At my
sexology clinic in Chennai we consult in Tamil and English,
so ask in whichever language is easier.

If any of these myths were stopping you from calling, let this be the nudge. A
two-minute phone call costs nothing. Waiting can cost a great deal.

PEP treatment: your questions answered

These are the questions people search for most, usually late at night. Short answers here. The detail is in the numbered sections above.

The bottom line

All said and done, PEP is not a fail-safe method of preventing HIV. But it is the best we
can do after an exposure, and it works best when you start in hours, not days, and finish all
28 of them.

If you take one thing from this page, take this: the clock started at the exposure.
Do not spend your hours reading forums. Spend two minutes on a phone call.

I hope this helped. This is Dr Shah, consultant
andrologist in Chennai. Please share this page with anyone who might need it one
day. On this subject, sharing really does help someone.

If you are worried about an exposure, get in touch with us below, or directly at the
address mentioned. We will help you through it.

References

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2. Tanner MR, et al. Antiretroviral Postexposure Prophylaxis After Sexual, Injection Drug Use, or Other Nonoccupational Exposure to HIV – CDC Recommendations, United States, 2025. 2025. PMID 40331832.
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