Syphilis Treatment: What You Are Given and How Long Before It Clears

Clinically reviewed by Dr. Pipat Finn, M.D., Senior Doctor, Doctor Pattaya. Last reviewed: August 2026

You got a result you were not expecting. Or you are still waiting on one and your stomach is in knots. Maybe you are three days into a Pattaya holiday and this was absolutely not part of the plan. Maybe you are an expat who has been putting off getting tested for months and finally did it. Either way, you need to know what happens next and whether the treatment actually works.

It does. Syphilis is curable. Here is exactly what to expect.

The short version: a penicillin injection, one or three doses depending on your stage, clears the bacteria. A few follow-up blood tests confirm it is gone. That is genuinely the whole story for most people. The longer version is what this article covers, because the details matter when you are making real decisions about your health.

How Syphilis Is Diagnosed Before Treatment Begins

No responsible doctor gives you an injection before confirming what you actually have. At Doctor Pattaya, a same-day blood test checks for syphilis using two types of markers. The first is a treponemal antibody test such as TPHA, which detects whether your body has responded to the infection. The second is a non-treponemal test such as RPR, which reflects how active the infection currently is.

The RPR result comes with a titer, which is a number. That number becomes your baseline for confirming the treatment has worked, so getting it before you start matters.

In most cases, results come back quickly enough to confirm the diagnosis and give the first injection during the same visit. You can read more about STD testing and treatment options in Pattaya if you are not sure what to expect before you arrive.

Stage-by-Stage Syphilis Treatment

What you are given depends entirely on your stage. This is the most important thing to understand before you walk into a clinic.

Primary and Secondary Syphilis

Primary syphilis usually shows up as a painless sore, often on the genitals or mouth. Secondary syphilis comes weeks later with a rash, flu-like symptoms, and sometimes mouth sores. Both stages respond to a single intramuscular injection of benzathine penicillin G, 2.4 million units given into the muscle. One injection, and that is it for most people.

This is genuinely good news if you are in Pattaya for a limited time. The treatment is complete before you leave.

Latent Syphilis

Latent syphilis means the bacteria are in your body but you have no symptoms. Early latent is within the first year of infection. Late latent is anything beyond that, or when the timeline is unclear.

Late latent syphilis needs three injections of benzathine penicillin G, one per week for three consecutive weeks. Missing a dose by more than a day or two may mean starting the course again.

If you are leaving Pattaya before the course is finished, tell your doctor at the first visit. We can discuss your options, including an oral doxycycline regimen in some cases, and help you arrange continued care wherever you are heading.

Tertiary Syphilis and Neurosyphilis

Tertiary syphilis is the late stage where the infection has begun affecting organs. Neurosyphilis means it has reached the nervous system. Both require intravenous penicillin given daily in a hospital setting and need specialist input.

If you have neurological symptoms alongside a syphilis diagnosis, such as vision changes, confusion, or severe headaches, get assessed the same day. Do not wait.

What to Expect on the Day of Your Injection

The injection goes into the gluteal muscle, the upper outer area of your buttock. Benzathine penicillin G is a thick solution. The injection takes around ten to fifteen seconds and is uncomfortable rather than painful. Most patients say the soreness that follows for a day or two is the main issue, not the injection itself.

You do not need to fast or prepare anything beforehand. You do need to tell your doctor about any allergy history before the injection is given. Sit or lie down for fifteen minutes afterward as a precaution. That is standard practice everywhere.

The Jarisch-Herxheimer Reaction

This is the one that sends people back to Google at two in the morning after their injection, so let us cover it properly.

A few hours after the first injection, some people develop fever, chills, headache, and muscle aches. This is not an allergic reaction and it is not the syphilis getting worse. It is your immune system reacting to the bacteria dying off quickly, and it feels like a bad flu hitting fast.

It almost always resolves within twenty-four hours. Paracetamol and plenty of water are enough for most people. Do not take ibuprofen if you are pregnant.

Come back in if the fever has not settled after twenty-four hours, if symptoms are still present at forty-eight hours, or if you develop hives, lip or throat swelling, or any difficulty breathing. Doctor Pattaya is open around the clock, so if you feel rough at midnight after your injection, we are here.

If You Are Allergic to Penicillin

Penicillin allergy does not leave you without options, as long as you are not pregnant.

For non-pregnant patients with a documented penicillin allergy, doxycycline 100 mg twice daily is the standard alternative. The course is fourteen days for primary or secondary syphilis and twenty-eight days for late latent. It works well but requires strict daily adherence. Oral antibiotics are less forgiving than a single injection.

Pregnancy changes everything here. Doxycycline cannot be used during pregnancy because of risks to the baby. Pregnant patients with a penicillin allergy need to be desensitised to penicillin and then treated with it, in a clinical setting. Congenital syphilis, where the infection passes to the baby, is a serious risk that makes prompt treatment non-negotiable. If this applies to you, raise it with your doctor the same day.

Syphilis Treatment With HIV Co-infection

If you have syphilis and HIV at the same time, the treatment drugs are the same. What changes is your follow-up schedule. Immune suppression can affect how quickly your RPR titer drops, so more frequent blood test monitoring is needed and the threshold for repeat treatment is lower.

Tell your doctor about your HIV status and current treatment before the injection is given, so the right follow-up plan is in place from the start.

Follow-Up Blood Tests and What the Numbers Mean

Treatment success is not confirmed by how you feel. It is confirmed by your RPR titer dropping over time.

The benchmark is a fourfold decline. If your starting titer was 1:64, the target at six to twelve months is 1:16 or lower. If you hit that, treatment has worked. If the titer stays the same or rises, it may mean reinfection or treatment failure, and further assessment is needed.

One thing that confuses a lot of expats: the TPHA treponemal test often remains positive for life, even after a confirmed cure. This does not mean the infection is still active. It is simply a scar in the blood test record. The RPR titer is the number that tells you what is actually happening right now.

A condition called serofast means the RPR stays at a low level without continuing to drop. It does not always mean treatment has failed. Your doctor will look at the full picture before deciding whether retreatment is needed.

Getting Syphilis Treatment in Pattaya

Walk-in access is one of the practical advantages of getting care at Doctor Pattaya. No appointment needed. The blood tests that confirm the diagnosis run on the same visit, and if the results support it, the first injection can be given the same day.

For tourists leaving within a week or two, early-stage syphilis is fully treated in one visit. For late latent syphilis requiring three weekly doses, we will be honest with you about the timeline and work out the best plan, whether that means completing the course here or giving you everything you need to continue care elsewhere.

Follow-up RPR tests at three, six, and twelve months can be done at any reputable lab wherever you are. Results can be forwarded to us for continuity if you are no longer in Thailand. We also offer doctor hotel visits across Pattaya, Jomtien, and Naklua if coming into the clinic is difficult.

Partner Notification and Treating Contacts

If you test positive, anyone you have had sexual contact with in the past ninety days should be tested and possibly treated. This applies to primary and secondary syphilis. For late latent syphilis, the contact window extends further.

Partners can be assessed and treated quickly, without a long wait or complicated referral. Some may be offered presumptive treatment while their results are pending, particularly if they are symptomatic or at higher risk. The clinic handles all of this discreetly.

After Syphilis Treatment — Reducing Your Risk Going Forward

Syphilis does not leave you immune. Reinfection is entirely possible, and it is more common among people with multiple or new partners. Regular STI screening is the most effective tool you have.

If you are at higher ongoing risk, particularly if you are a man who has sex with men, PrEP for HIV and regular syphilis and gonorrhoea screening should be discussed together. There is also strong emerging evidence for doxy-PEP, taking doxycycline within seventy-two hours of unprotected sex to reduce the risk of bacterial STIs including syphilis. The CDC now includes this in guidance for certain high-risk groups. Ask your doctor whether it makes sense for your situation.