There is no way to prevent syphilis by taking oral medications. If a patient wants to prevent syphilis by taking oral medication after having high-risk sex, this is clinically impossible. In order to prevent syphilis, the first thing you need to do is to eliminate high-risk sex, especially high-risk sex without safety measures. Syphilis can also be transmitted in other ways, such as through blood transfusions and sharing intimate items such as towels and underwear.