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Antibiotics for Syphilis

Examples

Penicillin is the antibiotic most commonly used to treat syphilis. Penicillin is usually given as a shot (injection).

If you are allergic to penicillin, your doctor may prescribe another antibiotic in early stages of syphilis, such as doxycycline, tetracycline, ceftriaxone, or azithromycin. Or he or she may desensitize you so that you can safely take penicillin. Later stages of syphilis may require treatment with penicillin.

Penicillin is the only antibiotic that should be used during pregnancy. If you are pregnant and think you may be allergic to penicillin, discuss your allergy with your doctor.

How It Works

Antibiotics destroy the bacteria that cause syphilis.

Why It Is Used

Antibiotics are needed if you have a positive blood test for syphilis during routine screening or have symptoms suggestive of syphilis. Exposed sex partners of a person with syphilis and babies born to women who have syphilis also need treatment.

The amount of antibiotics used and how often the medicine is taken are based on the stage of the illness. For example, if neurosyphilis is present, you will need to receive antibiotics for 10 days to 2 weeks.

How Well It Works

Treatment with penicillin cures most cases of syphilis in any stage. Antibiotics prevent further complications of syphilis but may not reverse damage that has already occurred.

A follow-up exam and a blood test for cure should be done at 6 and 12 months after the antibiotics are given (and may be done at 24 months after latent syphilis) to be sure the infection is cured.

If human immunodeficiency virus (HIV) infection was also present at the time of treatment, follow-up exams and blood tests should be done at 3, 6, 9, 12, and 24 months.1

Syphilis passed to a baby from the mother (congenital syphilis) may be prevented if the woman is treated before the 16th to 18th weeks of her pregnancy. Treatment after 16 to 18 weeks will cure the infection and stop the damage to the baby. But it may not reverse damage already caused by the infection.

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

  • Usually the benefits of the medicine are more important than any minor side effects.
  • Side effects may go away after you take the medicine for a while.
  • If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Call 911 or other emergency services right away if you have:

  • Trouble breathing.
  • Swelling of your face, lips, tongue, or throat.

Call your doctor if you have:

  • Hives.
  • Severe belly pain or cramps.
  • Decreased urine.
  • Depression.
  • Nausea or vomiting.
  • Unusual bleeding or bruising.

Common side effects of this medicine include:

  • Diarrhea.
  • Headache.
  • Mouth sores.
  • Vaginal itching or discharge.

A Jarisch-Herxheimer reaction is a fairly common reaction to antibiotic treatment of syphilis that involves fever and headache. It may occur up to 8 hours after the first treatment of early syphilis. The reason the Jarisch-Herxheimer reaction occurs is not clear. But it may be caused by the toxins released from the syphilis bacteria as they are destroyed by antibiotics. A Jarisch-Herxheimer reaction is not the same as an allergic reaction to penicillin.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Antibiotic treatment can cure syphilis. And it can prevent complications. The complications of tertiary-stage or congenital syphilis may not be reversed with treatment. But the progression of the disease will be stopped.

Penicillin is the preferred drug for treating syphilis. And penicillin is the standard therapy for the treatment of neurosyphilis, congenital syphilis, or syphilis acquired or detected during pregnancy. But other antibiotics (such as ceftriaxone) may be used.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.

Advice for women

If you are pregnant, breast-feeding, or planning to get pregnant, do not use any medicines unless your doctor tells you to. Some medicines can harm your baby. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. And make sure that all your doctors know that you are pregnant, breast-feeding, or planning to get pregnant.

Checkups

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Complete the new medication information form (PDF)new medication information form (PDF)(What is a PDF document?) to help you understand this medication.

References

Citations

  1. Centers for Disease Control and Prevention (2010). Syphilis section of Sexually transmitted diseases treatment guidelines, 2010. MMWR, 59(RR-12): 26–39. Also available online: http://www.cdc.gov/std/treatment/2010/default.htm.

Credits

By Healthwise Staff
Kathleen Romito, MD - Family Medicine
Kirtly Jones, MD - Obstetrics and Gynecology
Last Revised October 8, 2013

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

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