 The risk of syphilis can be decreased by latex condom use or not having sex . Syphilis can be effectively treated with antibiotics . The preferred antibiotic for most cases is benzathine penicillin G injected into a muscle . In those who have a severe penicillin allergy , doxycycline or tetracycline may be used . In those with neurosyphilis intravenous penicillin G potassium or ceftriaxone is recommended . During treatment people may develop fever , headache , and muscle pains , a reaction known as Jarisch @-@ Herxheimer . 
