Adherence to doxycycline for uncomplicated genitourinary chlamydia: A prospective observational study

Since 2020, the Center for Disease Control and Prevention (CDC) no longer recommends single-dose azithromycin as first-line therapy for uncomplicated genitourinary chlamydia, advising instead a 7-day course of doxycycline. Our study investigates self-reported adherence to the new regimen, reasons for nonadherence, and the impact of dispensing the regimen on-site compared to prescribing it.

We performed a prospective observational study of adult patients treated for suspected or laboratory-confirmed uncomplicated genitourinary chlamydia at three urban emergency departments (EDs), where patients receive a prescription for doxycycline, and in a sexually transmitted infection (STI) clinic, where the 14 doxycycline pills are dispensed on-site. Clinical data were extracted from electronic medical records and patients were interviewed regarding adherence via telephone 2-4 weeks after their index visit.

We enrolled 127 STI clinics and 201 ED patients. Therapeutic adherence was reported by 85% of STI clinic patients and 77% of ED patients. In the ED setting, younger age and female sex were associated with nonadherence, with only 67% of female patients reporting adherence. Reported reasons for nonadherence included medication adverse effects, financial and transportation barriers, skepticism of the need for therapy, and misunderstanding of discharge instructions, among others.

A considerable portion of patients treated for uncomplicated genitourinary chlamydia in urban EDs and STI Clinics report nonadherence to the 7-day doxycycline regimen. The CDC recommendation to consider azithromycin when nonadherence is a "substantial concern" should be applied broadly in these settings by routinely discussing barriers to adherence when selecting the optimal antimicrobial regimen. The benefit of dispensing the doxycycline regimen on-site compared to prescribing it could not be determined given differences in baseline characteristics between the two groups.