Treating syphilis 

Primary and secondary syphilis can be successfully treated with a single dose of penicillin, which is given as an injection into your buttock.

You will be prescribed another antibiotic in tablet form if you are allergic to penicillin.

Later stages of the disease need to be treated with three penicillin injections, which are given at weekly intervals.

Treatment usually lasts around two weeks, but can take longer in some cases.

Side effects of antibiotics

Some of the antibiotics used to treat syphilis can interfere with methods of contraception that contain the hormones oestrogen and progestogen, such as the combined pill or contraceptive patch.

Tell your doctor or nurse if you are using these methods of contraception so they can advise you on additional contraceptive methods to prevent you getting pregnant.

Refrain from any kind of sexual activity or close physical contact with another person until your treatment is complete and your sexual partner has been tested and treated.

Jarisch-Herxheimer reaction

A small number of people experience a reaction to the antibiotics, which is known as the Jarisch-Herxheimer reaction. It is thought that the reaction is triggered by the toxins released when a large number of bacteria are killed after antibiotic treatment.

The Jarisch-Herxheimer reaction causes flu-like symptoms such as fever, headaches and muscle and joint pain. These normally only last 24 hours, are nothing to worry about, and cause no serious problems.

The symptoms can be treated with paracetamol, but contact your GP or the genitourinary medicine (GUM) clinic if the symptoms are severe or do not settle down.

Follow-up test

Once the course of antibiotics has finished, you will be asked to return to the GUM clinic so a follow-up blood test can be carried out to check that the infection has gone.

You can still catch syphilis again, even after you have been successfully treated for it.

Tertiary syphilis

Treatment of tertiary syphilis requires longer courses of antibiotics and may need intravenous treatment (administered directly into the vein). While treatment can stop the infection, it cannot repair any damage that has already been caused by the tertiary syphilis.

Telling your partner

If you have syphilis, it is important that your current sexual partner, or any sexual partner you have had since being exposed to infection, is tested and treated.

Some people can feel angry, upset or embarrassed about discussing syphilis with their current partner or former partner. Do not be afraid to discuss your concerns with the clinic staff or your GP. They can advise you about who should be contacted and the best way to contact them.

The clinic can give you a "contact slip" to give to your partner or partners. This slip explains to that person that they may have been exposed to syphilis and that they should go for a check-up. The slip does not have your name on it and your details will remain totally confidential.

If you would prefer, the clinic can contact your recent partner for you. This is usually done by phone or letter. Again, your details will remain totally confidential and your partners will be given no information about you without your consent.

Nobody can force you to tell any of your partners about your syphilis, but it is strongly recommended. If it is left untested and untreated, syphilis can lead to death.


Syphilis in pregnancy can be successfully treated using antibiotics. There are no risks to your unborn baby from the antibiotics.

It is vitally important that pregnant women receive treatment for syphilis because it can cause serious birth defects, miscarriage or stillbirth if it is left untreated.

Avoiding sex

Do not have vaginal, anal or oral sex and avoid any kind of skin contact with your partner until you have finished treatment.

Otherwise, you could be infected again or you could pass the infection on to someone else.

Page last reviewed: 05/06/2014

Next review due: 05/06/2016