• Benzathine penicillin, 2.4 million units injected into a muscle (IM) as a single dose
• Doxycycline 100 mg (milligrams) by mouth twice per day for 15 days
• Tetracycline 500 mg by mouth four times per day for 15 days
• Erythromycin 500 mg by mouth four times per day for 2 weeks
• Ceftriaxone 250 mg IM daily for 10 days

• Benzathine penicillin 2.4 million units IM weekly for 3 weeks
• Doxycycline 100 mg by mouth twice per day for 30 days
• Tetracycline 500 mg by mouth twice per day for 30 days

• Aqueous penicillin G 12 to 24 million units injected into a vein (IV) daily for 10 days followed by benzathine penicillin 2.4 million units IM once a week for 3 weeks
• Procaine penicillin 2.4 million units IM daily; given with oral probenecid 500 mg four times per day--both for 10 days. This is followed by benzathine penicillin 2.4 million units once a week for 3 weeks.

Syphilis during pregnancy:
Penicillin is recommended as the only real drug of choice. Tetracycline can not be used because of toxicity to the fetus and erythromycin may fail to prevent congenital syphilis in the fetus. Penicillin-allergic individuals should be desensitized and then treated with penicillin.

Several hours following treatment of early stages of syphilis individuals may undergo a febrile reaction called Jarish-Herxheimer reaction. Symptoms of this reaction include:

• Fever
• Chills
• Headache
• Nausea
• General feeling of being ill (malaise)
• Generalized joint aches (arthralgia)
• Generalized muscle aches (myalgia)

Complications include a progression of symptoms.