An antibiotic that is taken once as the “morning after pill” can significantly reduce infection with bacterial sexually transmitted diseases such as syphilis, gonorrhea or chlamydia. If the pill is taken within 72 hours of unprotected sex, around two-thirds of infections can be prevented, according to an international study published Wednesday in the New England Journal Of Medicine.
Taking antibiotic doxycycline
The study included men who have sex with men and trans women who are taking HIV prophylaxis or are already living with HIV infection. All subjects had been infected with a sexually transmitted disease in the year before the start of the study. On average, participants took the antibiotic doxycycline four times a month during the study.
Patients who take HIV prophylaxis often have unprotected sex, explained Georg Stary from the Institute of Dermatology at the University of Vienna. Some of them are infected with many sexually transmitted diseases.
If fewer people in this group contracted syphilis, gonorrhea or chlamydia due to taking doxycycline, there were fewer sexually transmitted diseases in circulation overall. “Accordingly, those who do not take the drug prophylactically may also be protected under certain circumstances,” he explained.
Consider antibiotic resistance
However, antibiotic resistance must be considered. There was increased resistance in gonococci that transmit gonorrhea. Therefore, the application cannot be generally recommended. If at all, it only makes sense for a selective group.
Long-term use is also not recommended. “One has to assume that there will be a significant change in the microbiome and that side effects will increase with long-term use,” explained Norbert Brockmeyer from the Center for Sexual Health and Medicine at the Catholic Clinic in Bochum.