Chlamydia trachomatis is a bacterium responsible for one of the most common sexually transmitted infections worldwide. This infection frequently affects the urogenital tract but often presents without noticeable symptoms, allowing it to spread easily. If left untreated, chlamydia can cause serious reproductive complications. Fortunately, it is a curable infection when treated correctly with antibiotics.
Standard First-Line Antibiotics
For uncomplicated chlamydia infection of the cervix, urethra, or rectum in non-pregnant adults, healthcare guidelines establish two primary antibiotic regimens. The preferred treatment is a 7-day course of doxycycline, a tetracycline-class antibiotic. This regimen involves taking 100 milligrams of doxycycline by mouth twice a day for seven days. Doxycycline is highly effective, often achieving a cure rate exceeding 95%, and is the superior choice for treating rectal chlamydia infections.
The alternative standard treatment is a single, one-gram oral dose of the macrolide antibiotic azithromycin. This one-dose approach is useful when adherence to a multi-day regimen is a concern. While convenient, the single-dose azithromycin regimen is slightly less effective than doxycycline, especially for infections in the rectum.
Both doxycycline and azithromycin inhibit the bacteria’s ability to synthesize proteins, stopping C. trachomatis from growing and reproducing. Completing the entire prescribed course of medication is necessary to ensure the infection is fully eradicated. Failure to take all the medication can lead to treatment failure and persistent infection.
Alternative Treatments for Specific Cases
When standard treatments cannot be used, alternative antibiotics are necessary, particularly in unique patient populations. Doxycycline is contraindicated in pregnant patients because it can affect fetal bone and tooth development. Therefore, the preferred first-line treatment during pregnancy is a single, one-gram oral dose of azithromycin, which is safe and effective throughout all trimesters.
If azithromycin cannot be tolerated, the alternative regimen for pregnant patients is amoxicillin, taken as 500 milligrams three times a day for seven days. For non-pregnant patients allergic to tetracyclines or macrolides, a fluoroquinolone antibiotic like levofloxacin may be used, typically prescribed as 500 milligrams once daily for seven days.
Rectal chlamydia requires special consideration because it can be caused by different strains of the bacteria. Uncomplicated rectal chlamydia is treated with the standard 7-day doxycycline regimen. If the aggressive serovars that cause Lymphogranuloma Venereum (LGV) are suspected, the doxycycline regimen is prolonged to 100 milligrams twice daily for a total of 21 days.
Post-Treatment Guidelines and Follow-Up
Successful treatment depends on strict adherence to the prescribed antibiotic regimen. Patients must take all doses to achieve a complete cure. To prevent spreading the infection, sexual activity must be avoided for seven days following treatment or until all sexual partners have been treated.
Treating all recent sexual partners is crucial to prevent immediate reinfection. Healthcare providers often use Expedited Partner Therapy (EPT), where a patient is given medication or a prescription for their partner without an exam. Partners who had sexual contact with the infected individual within 60 days before the patient’s diagnosis should be evaluated and treated.
A Test of Cure (TOC), which confirms eradication, is generally not required for non-pregnant individuals who completed standard treatment. However, a TOC is strongly recommended for all pregnant women, performed three to four weeks after treatment completion. Retesting is recommended for all patients about three months after treatment to check for a new infection, as the risk of reinfection remains high.