The increasing use of doxycycline as post-exposure prophylaxis (doxyPEP) to prevent sexually transmitted infections (STIs) is raising concerns among researchers about the potential for increasing antibiotic resistance. While doxyPEP has shown promise in reducing the risk of chlamydia and syphilis, particularly among gay, bisexual, and other men who have sex with men (gbMSM), and trans women, its widespread adoption could have unintended consequences for the effectiveness of doxycycline and other antibiotics.
DoxyPEP involves taking a dose of doxycycline after sexual activity. Studies have demonstrated its effectiveness in preventing bacterial STIs, though it is generally less effective against gonorrhea. The initial clinical trial conducted in San Francisco and Seattle showed low rates of bacterial resistance to doxycycline. In fact, the study even suggested a reduction in the risk of gonorrhea, in addition to chlamydia, and syphilis. However, experts caution that these results may not be universally applicable as doxyPEP is implemented in different regions.
The concern stems from the fact that doxycycline belongs to a class of antibiotics called tetracyclines. These antibiotics were previously used extensively to treat gonorrhea, leading to the development of resistance in gonorrhea-causing bacteria. This resistance persists globally, and in some areas, such as France, widespread tetracycline use has resulted in widespread doxycycline resistance. A recent clinical trial in France found that doxyPEP effectively reduced the risk of chlamydia and syphilis but did not offer the same protection against gonorrhea.
Antibiotic resistance develops when bacteria mutate in response to exposure to antibiotics. This can occur even when the antibiotic is taken as prescribed, but is more likely with improper use or insufficient dosage. When bacteria become resistant, the antibiotics designed to kill them become less effective, potentially leading to infections that are harder to treat and can spread more easily. The World Health Organization (WHO) has identified antimicrobial resistance as a global health threat.
Currently, ceftriaxone is the most effective treatment for gonorrhea, administered via intramuscular injection. Ceftriaxone is also used to treat other serious bacterial infections, such as certain types of pneumonia. The potential for doxycycline resistance, extends beyond the realm of STIs, potentially impacting the treatment of other conditions.
The San Francisco Department of Public Health and the San Francisco AIDS Foundation began recommending doxyPEP in late 2022 to individuals at higher risk for STIs. This recommendation sparked questions from the community regarding the potential for drug resistance. Experts emphasize the importance of discussing the potential benefits and risks of doxyPEP with a healthcare provider before starting the regimen.
The dilemma lies in balancing the individual benefits of STI prevention with the broader public health implications of antibiotic resistance. While doxyPEP offers a valuable tool for reducing the incidence of chlamydia and syphilis, the potential for diminishing doxycycline’s effectiveness – and potentially impacting other antibiotics – requires careful consideration. Ongoing monitoring of antibiotic resistance patterns is crucial as doxyPEP becomes more widely adopted. Further research is needed to fully understand the long-term effects of widespread doxycycline use and to develop strategies to mitigate the risk of resistance.
The CATIE blog highlights the importance of understanding the nuances of antibiotic resistance and the potential impact of preventative measures like doxyPEP. The blog emphasizes that while doxyPEP can be beneficial for certain populations, it is not a foolproof solution and does not eliminate the need for regular STI screening and safe sex practices.
the decision to use doxyPEP should be made in consultation with a healthcare professional, taking into account individual risk factors, potential benefits, and the evolving understanding of antibiotic resistance. Continued research and public health surveillance will be essential to navigate this complex issue and ensure the continued effectiveness of antibiotics for generations to come.
