The most effective remedy for treating syphilis is benzathine penicillin, which should always be given as an injection and the dose varies according to the staging of the disease.
In case of allergy to this drug other antibiotics such as tetracycline, erythromycin or ceftriaxone can be used, but penicillin is the most effective medicine being always the first choice. Before testing another antibiotic one should opt for desensitization to penicillin so that the treatment can be done with this same drug. Desensitization consists of applying small doses of penicillin until the body can not reject it.
The treatment schedule should be done according to your doctor's guidelines but may be:
| Phase of the disease | Dose of penicillin | Other medications |
| Primary syphilis | 1 injection of 2, 400, 000 IU benzathine penicillin. | Doxycycline, 100 mg 2x / day or Tetracycline, 500 mg 4x / day or both for 14 days |
| Secondary syphilis | 2 injections of 1, 200, 000 IU of benzathine penicillin at two different sites of the body. | Doxycycline, 100mg 2x / day or Tetracycline, 500mg 4x / day or both for 14 days |
| Tertiary syphilis | 3 injections of penicillin with 2, 400, 000 IU in different places of the body, with interval of 7 days each dose | Doxycycline, 100mg 2x / day or tetracycline, 500mg 4x / day, both for 28 days |
| Neurosyphilis | 6 daily injections of Penicillin G Crystalline with 2 to 4 million for 10-14 days | Procaine penicillin, 2.4 million UI / IM / day, + Probenecid 500mg / VO / 4x / day or both for 14 days |
| Congenital syphilis |
Penicillin G Crystalline 100 to 150 mil or | Not indicated |
| Syphilis in pregnancy | Penicillin G Benzathine | Erythromycin 500 Stearate mg VO, of 6/6 hours for 10 days or until the cure |
Test for allergy to penicillin
The test to know if the person is allergic to penicillin is to rub a small amount of this medicine into the skin and see if the site shows any signs of reaction such as redness or itching. If these signs are present the person has an allergy.
This test should be performed by a nurse in a hospital environment and is usually done on the skin of the forearm.
How penicillin desensitization is done
Desensitization to penicillin is indicated in case of allergy to this drug, especially in case of treatment for syphilis during pregnancy and treatment for neurosyphilis. This withdrawal of sensitivity to penicillin should be done at the hospital, and tablet use is the safest form.
There is no indication for the use of antihistamines or steroids prior to taking penicillin because these medications do not prevent the anaphylactic reaction and may mask their first signs delaying treatment.
After the procedure, penicillin should be started. If the person spends more than 28 days without having any contact with this medicine, it is necessary to check again for signs of allergy and if they are present, desensitisation should be started again.
Common penicillin reactions
After the injection, symptoms such as fever, chills, headache, pain in the muscles and joints may appear 4 to 24 hours after the injection. To control these symptoms the doctor may recommend taking an analgesic or antipyretic.
When penicillin is contraindicated
Treatment for syphilis can not be done with penicillin in case of Stevens-Johnson syndrome, toxic epidermal necrolysis and exfoliative dermatitis. In these cases, treatment for syphilis should be done with other antibiotics.
