Doxy PrEP for Comprehensive STI Prevention
Rates of sexually transmitted infections (STIs), like gonorrhea, chlamydia, and syphilis, have gradually risen among gay, bisexual, and other men who have sex with men (MSM) in the US over the past two decades, potentially due to a reduction in condom use and the insufficient adoption of Doxy PrEP. This trend has fueled the spread of bacterial STIs.
New groundbreaking research indicates that a dose of doxycycline — a potent antibiotic — effectively prevents several STIs after unprotected sex. Studies on this subject have provoked significant reactions across the medical community.
A 2022 study from the University of California, titled Evaluation of Doxycycline Post-exposure Prophylaxis to Reduce Sexually Transmitted Infections in PrEP Users and HIV-infected Men Who Have Sex With Men, is ongoing, with only preliminary data being released.
Best of all, as the trial is in the final phase (Phase IV), if successful, it could see a quick roll-out of the treatment across the US, helping to tackle the bacterial STI rise.
What is Doxy PrEP?
It is a course of treatment involving daily doxycycline as a preventative action against bacterial STIs. It should not be confused with Doxy post-exposure prophylaxis or Doxy PEP, where the doxycycline is taken 24 to 72 hours after an episode without a condom.
In the current study, under the supervision of their primary care doctor, the 637 participants take 200 mg of doxycycline or a placebo as PEP — after they practice unprotected sex. Confusion between these two treatment types is enhanced as many men in the trial also take HIV PrEP.
How Fast Does Doxycycline Work?
For most infections, doxycycline takes between 3 to 7 days to work. Depending on the infection in question, it may take anywhere from 1 week to 3 months for the full benefits to take effect.
That will differ for Doxy PEP or Doxy PrEP. In the former, patients in the current trial receive a single dose in a 24-hour period after condomless sexual contact — in the latter, doxycycline is taken continuously.
It's hoped that taking Doxy PEP once shortly after infection will increase its efficacy, reducing the need for longer treatment times.
How Long Does Doxycycline Stay in Your Body?
Doxycycline has a half-life of between 16 to 22 hours — meaning it takes that long for half the dose of doxycycline to be eliminated. For all the doxycycline to be eliminated from your system, it takes approximately 5 days. Your elimination rate will depend on your age and health, body mass (the bigger you are, the longer the drug remains), and metabolic rate.
Doxy PrEP vs. Doxy PEP
In a nutshell, Doxycycline PrEP involves taking the antibiotic before any infection occurs, and Doxy PEP involves taking the antibiotic immediately after the infection may have occurred.
Many people will naturally wonder why, if HIV PrEP is so effective, we do not take a pre-exposure prophylactic for bacterial infections. Surely, it would also work. The chances are it would. However, there is a secondary concern.
The potential benefits of taking doxycycline as a long-term prophylactic against bacterial STIs are likely outweighed by the risk of selecting resistance — that is, antibacterial strains resistant to the antibiotic.
Antibiotic resistance is a major concern. The more an antibiotic is used, the more we select for the strains of bacteria resistant to its effect.
Final Thoughts
Many argue that Doxy PrEP is a targeted intervention that treats potential bacterial infections before they take hold, thereby reducing significant infections and potential complications. Results, as we have seen, seem to back up this perspective.
Few ignore these benefits, even medical professionals concerned about potential risks. However, some concern is still that Doxy PEP could promote antibiotic resistance. Indeed, in France, over 50% of gonorrhea strains are resistant to tetracyclines — the class of antibiotics to which doxycycline belongs.
For now, we await the results of the ongoing trials to see if this is a reliable form of treatment to manage the growth of bacterial STIs.