Are you looking to self medicate?
Benzathine penicillin G 2.4 million units IM in a single dose is what the cdc 2006 guidelines suggest if it's early latent - otherwise it's Benzathine penicillin G 50,000 units/kg IM, up to the adult dose of 2.4 million units, administered as 3 doses at 1-week intervals (total 150,000 units/kg up to the adult total dose of 7.2 million units). Talk to your doctor about what dose is best for you. were you properly diagnosed or did you have pcn for something else and are just wondering if it would've covered syphilis too?
grace