Non-Adherence – Doxycycline’s Weakness for Treatment of STI

August 22, 2024

Written by Samuel Rouleau

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A single center retrospective treatment of 144 patients who tested positive for C. trachomatis found that 18% (n=26) of patients did not pick up their prescription for doxycycline. Those who did not obtain their doxycycline prescription were 3 times more likely to return to the ED within 28 days for the same chief complaint.

Chlamydia be gone!
The CDC updated its treatment guidelines for sexually transmitted infections in 2021. For patients with Chlamydia, the guidelines recommended a 7-day course of doxycycline over the previous first-line treatment of one-time dose of azithromycin. This retrospective study of a single ED in Chicago found that in 144 patients who tested positive for Chlamydia trachomatis, 26 (18%) did not pick up their prescription for doxycycline. When comparing those who picked up the prescription versus those who did not, there was no significant difference in insurance status, housing status, demographics, sexual orientation, or history of STI. Those who did not obtain their doxycycline prescription were 3 times more likely to return to the ED within 28 days for the same chief complaint (OR 3.6, 95%CI 1.2 to 11.3).

This study’s largest limitation is how they defined adherence. One aspect of adherence is picking up the medication from the pharmacy. However, even if a patient does this, they may not take the prescription as prescribed. My instincts tell me that the study likely underestimated rates of non-adherence for this reason, though further work needs to be done to investigate this.

How will this change my practice?
This study exposes the tension between guideline recommendations and treatment adherence, especially when the best treatment is more difficult to adhere to than the next preferred treatment.

• Doxycycline is clearly preferred for the treatment of Chlamydia, but if the patient is not going to be adherent with a 7-day course of doxycycline, a one-time dose of azithromycin might be better than no or incomplete treatment.
• We should all consider factors that impact treatment adherence and use shared decision-making and clinical judgment when selecting therapies.

Source
Doxycycline adherence for the management of Chlamydia trachomatis infections. Am J Emerg Med. 2024;81:136-139. doi:10.1016/j.ajem.2024.05.003. PMID: 38728936.