5-FU injection and topical even in small doses cause both acute central nervous system (CNS) damage and progressively worsening delayed degeneration of the CNS in mice. This latter effect is caused by 5-FU-induced damage to the oligodendrocytes that produce the insulating myelin sheaths.
Home > Sexually transmitted infections > Syphilis > After treatment for syphilis. It is strongly advised that you do not have any sexual intercourse; including vaginal; anal or oral sex until you and your partner(s) have both finished the treatment and any follow-up treatment.
Risk of infection from oral sex: 1  Giving oral sex to a partner with a syphilis sore or rash on the genitals or anus can result in getting syphilis. 2  Getting oral sex from a partner with a syphilis sore or rash on the lips or mouth, or in the throat, can result in getting syphilis.