Chlamydia is a bacterial sexually transmitted infection (Chlamydia trachomatis) that often presents without noticeable symptoms, making routine screening important. If left untreated, this infection can cause serious complications, such as pelvic inflammatory disease (PID) in women or epididymitis in men. Chlamydia is curable with a short course of antibiotics, which eliminates the bacteria and prevents these health consequences. The specific antibiotic regimen selected depends on the infection site, potential for adherence, and individual patient circumstances.
Standard First-Line Treatments
The goal of antibiotic treatment is to achieve a high rate of cure for uncomplicated genital, rectal, and pharyngeal infections. Current guidelines prioritize doxycycline as the preferred first-line treatment for non-pregnant adults due to its superior efficacy, especially for rectal infections. This regimen involves taking 100 milligrams of doxycycline orally, twice daily, for seven days. Doxycycline remains the standard of care for most patients.
The alternative first-line option is a single 1-gram dose of azithromycin taken orally. This single-dose regimen is favored when there are concerns about a patient’s ability to complete the full seven-day course of doxycycline. Doxycycline is more effective than azithromycin for treating rectal C. trachomatis infection. Clinicians must weigh the benefit of improved adherence against the decrease in efficacy for certain infection sites.
Both medications are effective for treating urogenital infections, but doxycycline is preferred due to its superior efficacy for rectal sites. Azithromycin’s lower efficacy for rectal chlamydia is a concern, as inadequately treated infections can lead to reinfection of the urogenital tract. For uncomplicated infections, doxycycline and azithromycin form the backbone of treatment protocols.
Treatment for Specific Patient Groups
Antibiotic selection requires modification for specific patient populations where standard regimens may be contraindicated. Pregnant patients cannot be treated with doxycycline because it carries a risk of permanent tooth discoloration and bone development issues in the fetus. For these individuals, the preferred treatment is a 1-gram single oral dose of azithromycin.
If a pregnant patient cannot tolerate azithromycin, an alternative regimen is amoxicillin, taken as 500 milligrams orally three times a day for seven days. Azithromycin is generally preferred in pregnancy due to greater clinical experience and fewer concerns about compliance. Erythromycin is another potential alternative for those with severe allergies, though it is rarely used due to gastrointestinal side effects.
Patients presenting with complicated infections, such as pelvic inflammatory disease (PID) or epididymitis, require a different approach. These infections involve a longer course of antibiotics and may require a combination of drugs to cover a broader spectrum of bacteria. For example, treating epididymitis caused by chlamydia includes a 10-day course of doxycycline, often combined with a single dose of ceftriaxone to treat possible co-infection with gonorrhea.
Steps Following Antibiotic Treatment
Completing the antibiotic regimen requires specific behavioral and testing steps afterward. To prevent spread and avoid reinfection, patients must abstain from sexual activity for seven days after completing the full seven-day course of doxycycline. If the single-dose azithromycin regimen was used, the patient should still abstain for seven days following the dose.
A Test of Cure (TOC) is generally not recommended for non-pregnant individuals who received standard treatment. A TOC can produce a false-positive result if performed too soon because non-viable bacterial fragments can still be detected. However, a TOC is essential for pregnant patients, who should be retested approximately four weeks after completing treatment.
All patients should be retested for reinfection approximately three months after the initial treatment, or at the next healthcare visit within the following year. Retesting is necessary because of the high rate of reinfection, which often occurs when sexual partners were not treated. Treating all recent sexual partners prevents this “ping-pong” effect and reduces the risk of complications from repeat infection.