From the Guidelines
For patients with chlamydia who cannot tolerate doxycycline, azithromycin is the recommended alternative treatment, with a standard regimen of azithromycin 1 gram taken orally as a single dose 1. This recommendation is based on the guidelines from the Centers for Disease Control and Prevention, which suggest that azithromycin is a highly effective treatment for chlamydial urethritis 1. The advantages of azithromycin include improved compliance due to its single-dose regimen and the convenience of directly observed treatment. Some key points to consider when treating patients with chlamydia who are intolerant to doxycycline include:
- Abstaining from sexual activity for 7 days after treatment begins and until all partners have been treated to prevent reinfection
- Notifying, testing, and treating partners from the past 60 days, regardless of their test results
- Considering alternative treatments, such as levofloxacin 500 mg orally once daily for 7 days or erythromycin base 500 mg orally four times daily for 7 days, although azithromycin is generally preferred
- Retesting pregnant women 3-4 weeks after treatment, as a test of cure is not routinely recommended for uncomplicated chlamydia infections if the recommended treatment is completed. Azithromycin's mechanism of action, which involves binding to the 50S ribosomal subunit of susceptible bacteria and inhibiting protein synthesis, makes it effective against the intracellular Chlamydia trachomatis organism 1.
From the Research
Alternative Treatments for Chlamydia
In patients intolerant to doxycycline, alternative treatments for chlamydia include:
- Azithromycin: a single 1 g dose is as effective as a standard seven-day course of doxycycline 2
- Ofloxacin: 400 mg bid for seven days is also effective against Chlamydia trachomatis 2
- Erythromycin, ofloxacin, and levofloxacin: recommended as alternative-regimen by the Centers for Disease Control and Prevention (CDC) 3
Treatment Effectiveness
Studies have compared the effectiveness of azithromycin and doxycycline in treating chlamydial infections:
- A retrospective cohort study found that doxycycline may be more effective than azithromycin in treating rectal chlamydial infections 4
- A mathematical model estimated that doxycycline effectiveness may be 97% compared to just 82% for azithromycin when considering the possibility of autoinoculation from the rectum to the genitals 5
- A use-effectiveness study found that the use-effectiveness of single-dose and multidose therapy was comparably high, with similar rates of chlamydial persistence or recurrence 6
Considerations
When choosing an alternative treatment for chlamydia, considerations include:
- Resistance to antibiotics: in vitro resistance to azithromycin and doxycycline has been reported, although the clinical significance is unknown 3
- Patient compliance: single-dose regimens may be more convenient, while multidose regimens may require better patient compliance 6
- Cost: single-dose regimens may be more expensive than multidose regimens 6