US Pharm. 2024;49(10):32-34.

ABSTRACT: The CDC recently released clinical guidelines for the use of doxycycline as postexposure prophylaxis (PEP) to prevent bacterial sexually transmitted infections. The CDC strongly recommends that providers counsel men who have sex with men and transgender women with a history of syphilis, chlamydia, or gonorrhea in the past 12 months about the benefits and harms of using doxycycline PEP and offer doxycycline as part of a comprehensive sexual health approach for the prevention of these infections. With doxycycline PEP, an individual would be given a prescription for doxycycline and instructed to take 200 mg within 72 hours of oral, vaginal, or anal sex. Pharmacists are in a key position to actively work with patients to provide counseling and ensure appropriate monitoring for those receiving doxycycline PEP.

In 2022, there were 207,255 cases of syphilis, 1,649,716 cases of chlamydia infection, and over 648,000 cases of gonorrhea reported in the United States.¹ With these high numbers of reported cases, the CDC considers sexually transmitted infections (STIs) to be a public health priority.¹ Doxycycline postexposure prophylaxis (PEP) refers to taking doxycycline as soon as possible and within 72 hours of oral, vaginal, or anal sex to prevent syphilis, gonorrhea, and chlamydia infection after a possible exposure.² Doxycycline is a tetracycline antibiotic that has bacteriostatic activity against a variety of gram-positive, gram-negative, and atypical bacteria.³ Doxycycline is the recommended agent for treatment of chlamydia and an alternative option for treatment of syphilis in nonpregnant patients with a severe penicillin allergy.⁴ When doxycycline PEP was studied in clinical trials in men who have sex with men (MSM) and transgender women, it reduced rates of infections with syphilis and chlamydia by over 70% and rates of gonorrhea by approximately 50%.² Guidelines for the use of doxycycline as PEP for prevention of bacterial STIs were recently released by the CDC.² This article focuses on these clinical guidelines and reviews the current recommendations for use and monitoring of doxycycline prophylaxis.

GUIDELINE RECOMMENDATIONS

Populations

The CDC’s recommendations for doxycycline PEP are strongest for MSM and transgender women with a history of at least one infection with chlamydia, gonorrhea, or syphilis within the previous 12 months.² The CDC clinical guidelines strongly recommend that providers counsel MSM and transgender women about the risks and benefits of doxycycline PEP to prevent bacterial STIs and to offer doxycycline PEP using shared decision-making for those with a history of at least one infection with chlamydia, gonorrhea, or syphilis within the previous 12 months. Discussion and shared decision-making about doxycycline PEP can also be followed with MSM and transgender women who do not have a history of bacterial STI in the previous 12 months but who will be participating in sexual activities that increase the likelihood of STI exposure.²

The CDC does not have a recommendation on the use of doxycycline PEP for cisgender women, cisgender heterosexual men, transgender men, or other individuals because there is insufficient evidence to assess the benefits and harms of its use. The CDC states that although the pharmacokinetics of doxycycline and experience in treating bacterial STIs suggest that doxycycline should be effective in other populations, there are limited clinical data, so a recommendation cannot be made at this time. The CDC recommends that providers use clinical judgment and shared decision-making when considering prescribing doxycycline PEP for populations other than those for whom it is recommended.²

Medication Regimen

The recommended regimen of doxycycline PEP is 200 mg, self-administered by the individual for whom it was prescribed, taken as soon as possible and no later than 72 hours after oral, vaginal, or anal sex, with a maximum dosage of 200 mg within a 24-hour period (see TABLE 1).² Any formulation of doxycycline may be used for the purpose of PEP. The CDC recommends that a provider assess an individual’s ongoing need for doxycycline PEP every 3 to 6 months, and the quantity of doxycycline prescribed should account for the time period until the next provider visit. The total quantity of doxycycline prescribed should be based on behavioral assessment, considering an individual’s anticipated sexual activity until the next prescriber visit.²

Additional Clinical Services at Initial Visit

Doxycycline PEP should be used in conjunction with a comprehensive sexual health approach, focused on prevention and control of STIs.² These strategies should be followed when first discussing doxycycline PEP and include assessment of risk for STIs; education and counseling on how an individual can avoid STIs, including the regular use of condoms and use of recommended prevention services, such as HIV preexposure prophylaxis (PrEP); the use of preexposure vaccines (including those for hepatitis A virus, hepatitis B virus, human papillomavirus, and mpox, as indicated); screening and treatment for STIs in both asymptomatic and symptomatic individuals; and appropriate diagnosis, treatment, counseling, and follow-up of STI-infected individuals and their sexual partners.^2,4

At the initial doxycycline PEP visit, individuals should be screened for gonorrhea and chlamydia at anatomic sites of exposure and screened for syphilis with serologic testing and treated accordingly based on findings.² Linkage to care for accessing HIV treatment, HIV PEP, or HIV PrEP should be followed as indicated.² Recommended agents for HIV PrEP are included in TABLE 2.^5-9

MONITORING AND FOLLOW-UP

Providers should assess an individual’s ongoing need for doxycycline PEP every 3 to 6 months.² At follow-up visits, providers should evaluate whether a patient has had any issues related to tolerability or side effects of doxycycline and continue to provide STI risk–reduction counseling. At follow-up visits, providers should continue to follow CDC recommendations for screening, treatment, and prevention of STIs, including encouraging the use of HIV PrEP as indicated; screening for gonorrhea, chlamydia, and syphilis every 3 to 6 months in MSM and transgender women at increased risk for infection; screening for HIV at least annually in those with risk factors for infection, with consideration given to screening every 3 to 6 months for MSM at high risk for infection who are not receiving HIV PrEP; and assessing the need for HIV PEP.^2,4,10

CONCLUSION

Pharmacists play an integral role in the appropriate use of doxycycline as PEP of bacterial STIs. Pharmacists can educate patients about the importance of speaking with their provider to discuss the new CDC recommendations. Pharmacists should also be familiar with additional resources available in their area, including those from public health departments. Pharmacists can work with clinicians to determine whether doxycycline PEP is appropriate for an individual and provide education and counseling to patients on risk-reduction strategies for STIs, appropriate administration, avoidance of drug interactions, and potential side effects. Pharmacists are in a key position to actively work with patients and healthcare providers to ensure the appropriate use of doxycycline PEP to prevent bacterial STIs.

REFERENCES

1. CDC. Sexually transmitted infections (STIs). January 30, 2024. www.cdc.gov/std/statistics/2022/default.htm. Accessed July 13, 2024.
2. Bachmann LH, Barbee LA, Chan P, et al. CDC clinical guidelines on the use of doxycycline postexposure prophylaxis for bacterial sexually transmitted infection prevention, United States, 2024. MMWR Recomm Rep. 2024;73(2):1-8.
3. Vibramycin hyclate (doxycycline) product information. New York, NY: Pfizer, Inc; January 2024.
4. Workowski KA, Bachmann LH, Chan PA, et al. Sexually transmitted infections treatment guidelines, 2021. MMWR Recomm Rep. 2021;70(4):1-187.
5. CDC. US Public Health Service: Preexposure prophylaxis for the prevention of HIV infection in the United States—2021 update: a clinical practice guideline. www.cdc.gov/hiv/pdf/risk/prep/cdc-hiv-prep-guidelines-2021.pdf. Accessed July 13, 2024.
6. National Institutes of Health. Pre-exposure prophylaxis (PrEP). December 11, 2023. https://hivinfo.nih.gov/understanding-hiv/fact-sheets/pre-exposure-prophylaxis-prep. Accessed July 13, 2024.
7. Truvada (emtricitabine and tenofovir disoproxil fumarate) product information. Foster City, CA: Gilead Sciences, Inc; April 2024.
8. Descovy (emtricitabine and tenofovir alafenamide) product information. Foster City, CA: Gilead Sciences, Inc; January 2022.
9. Apretude (cabotegravir extended-release injectable suspension) product information. Durham, NC: ViiV Healthcare; December 2023.
10. CDC. Getting tested for HIV. January 18, 2024. www.cdc.gov/hiv/testing/index.html. Accessed July 13, 2024.

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

To comment on this article, contact rdavidson@uspharmacist.com.