Strategies to Reduce STIs: “Doxy-PEP”

HEALTH

Strategies to Reduce STIs: “Doxy-PEP”

by Vincent Betti

Background Information

Sexually transmitted infections (STIs), including gonorrhea, chlamydia, and syphilis, can pose serious health risk to patients. Thankfully, these infections respond well to treatment when detected early. The issue is that, particularly in people assigned male at birth, these infections can go undetected due to lack of symptoms, increasing transmission^(2). Men who have sex with men (MSM) make up one population that is affected by these unknown, asymptomatic infections⁽⁷⁾. There is work being done to decrease the rates of bacterial STIs, particularly through medications.

There has been a reduction in the rates of infection with HIV with advancements in both treating and preventing infection⁽⁶⁾. There are medicines to prevent infection, such as “PreP,” that people take every day, and there are medicines to eliminate the virus as well, such as “PEP”, that people take after sexual encounters⁽⁶⁾. It is more complicated to prevent bacterial infections, such as chlamydia or syphilis, than infections with a virus because antibiotics are used for bacterial infections, and they have more risks than antivirals. However, there is newer data that shows that using a specific antibiotic, doxycycline, as post-exposure treatment (PEP) to prevent infection with syphilis or chlamydia from progressing and getting transmitted is effective⁽⁴⁾.

Doxycycline – The Good and The Bad

Doxycycline is an antibiotic commonly used for specific bacterial infections, such as chlamydia and Lyme disease. It does not have serious side effects but can cause diarrhea and vomiting⁽¹⁾. It should not be taken with any milk-containing products because the milk will prevent the medicine from being absorbed by the body⁽¹⁾. It should also be avoided in pregnant patients to avoid harm to the fetus. Overall, it is a safe medication when taken as prescribed, though it is important to be consider side effects.

However, using it as post exposure prophylaxis for STIs is controversial. This is mainly because of a fear of antibiotic resistance, which is when the bacteria stop responding to antibiotics if taken for long periods of time⁽⁵⁾. Many experts opposed to Doxy-PEP believe that preventing some cases of these infections is not worth causing antibiotic resistance, which is why this strategy for prevention has not been made as public as HIV PreP/PE⁽⁸⁾.

Guidelines and Conclusion

Currently, the Center for Disease Control (CDC) has put out preliminary statements, but formal guidelines are still pending⁽³⁾. In November 2023, there was a call for public opinion on these preliminary guidelines. It is important to remember the potential side effects of this medication and to keep in mind that there is a risk for developing infections that are resistant to typical treatments before considering this regimen. At this time, the best advice is to discuss this with your doctor if you were assigned male at birth, have sex with men, had one of the STIs mentioned in this article in the last year, or have sex without condoms with multiple partners^(3,7,8).

Illustrations by Ellie Cheng and Nicholas Hall

References

1. DiMarco DE. NYSDOH AI doxycycline post-exposure prophylaxis to prevent bacterial sexually transmitted infections. HIVGuidelines.org. September 25, 2023. Accessed December 6, 2023. https://www.hivguidelines.org/wp-content/uploads/2023/09/NYSDOH-AI-Doxycycline-PEP-to-Prevent-Bacterial-STIs_11-7-2023_HG.pdf.
2. Farfour E, Dimi S, Chassany O, et al. Trends in asymptomatic STI among HIV-positive MSM and lessons for systematic screening.PLoS One. 2021;16(6):e0250557. Published 2021 Jun 24. doi:10.1371/journal.pone.0250557
3. Guidelines for the use of doxycycline post-exposure prophylaxis for bacterial STI prevention. Centers for Disease Control and Prevention. September 29, 2023. Accessed December 6, 2023. https://www.cdc.gov/std/treatment/guidelines-for-doxycycline.htm.
4. Molina JM, Charreau I, Chidiac C, et al. Post-exposure prophylaxis with doxycycline to prevent sexually transmitted infections in men who have sex with men: an open-label randomized sub study of the ANRS IPERGAY trial.Lancet Infect Dis. 2018;18(3):308-317. doi:10.1016/S1473-3099(17)30725-9
5. Park JJ, Stafylis C, Pearce DD, et al. Interest, Concerns, and Attitudes Among Men Who Have Sex With Men and Health Care Providers Toward Prophylactic Use of Doxycycline Against Chlamydia trachomatis Infections and Syphilis.Sex Transm Dis. 2021;48(9):615-619. doi:10.1097/OLQ.0000000000001395
6. Sun Z, Gu Q, Dai Y, et al. Increasing awareness of HIV pre-exposure prophylaxis (PrEP) and willingness to use HIV PrEP among men who have sex with men: a systematic review and meta-analysis of global data.J Int AIDS Soc. 2022;25(3):e25883. doi:10.1002/jia2.25883
7. Traeger MW, Mayer KH, Krakower DS, Gitin S, Jenness SM, Marcus JL. Potential impact of doxycycline post-exposure prophylaxis prescribing strategies on incidence of bacterial sexually transmitted infections.Clin Infect Dis. Published online August 18, 2023. doi:10.1093/cid/ciad488
8. Venkatesan P. Doxycycline PEP for prevention of STIs.Lancet Infect Dis. 2022;22(11):1545. doi:10.1016/S1473-3099(22)00674-0

Vincent (Vinny) is from Jessup, Pennsylvania. He graduated from Colgate University with degrees in biochemistry and Spanish literature in 2021 before starting as a medical student at the University of Rochester. He is dedicated to providing medical care to Spanish-speaking patients in Spanish, and for that reason he participates in the “LatinX Health Pathway” at the medical school. He wants to be a psychiatrist after graduating in 2025.