The epidemiologic control of syphilis would be greatly enhanced if gonorrhea therapy were simultaneously curative for incubating syphilis. In a cooperative study, schedules currently recommended by the Public Health Service for gonorrhea treatment in the male and female (aqueous penicillin G procaine, 2.4 and 4.8 million units, respectively) were evaluated in 127 patients exposed to infectious syphilis within a 30-day period. After a three-month clinical and serologic follow-up, these schedules were found to be 100% effective in aborting incubating syphilis. Of a control group of contacts treated with placebo who were exposed to infectious syphilis within 30 days preceding treatment, 30% developed syphilis. Consequently, aqueous penicillin G procaine in the dosage of 2.4 and 4.8 million units is curative therapy for patients with gonorrhea with coexisting incubating syphilis.
Schroeter AL, Turner RH, Lucas JB, Brown WJ. Therapy for Incubating SyphilisEffectiveness of Gonorrhea Treatment. JAMA. 1971;218(5):711–713. doi:10.1001/jama.1971.03190180033006