Antibiotics for Chlamydia Infection
- What is Chlamydia infection?
- First-choice antibiotics
- Alternative antibiotics
Updated according to 2015 Centers for Disease Control and Prevention (CDC) STD Treatment Guidelines 10.
Based on "Principles and Practice of Infectious Diseases"
written by John E. Bennett, MD
What is a Chlamydia infection?
Chlamydia genital infection is a sexually transmitted disease (STD) caused by the bacteria Chlamydia trachomatis. In fact, C. trachomatis is the most common sexually transmitted bacterial infection in the world. Interestingly, about 70% of genital infections are associated with few or no symptoms at all.
Chlamydial infections in women are more likely to remain asymptomatic than in men (80% vs 50%). However, women are more likely to develop long-term complications.
The best antibiotics for Chlamydia: first-choice drugs
Chlamydia can be easily treated and cured with antibiotics. However, not all antibiotics are effective.
The Centers for Disease Control and Prevention (CDC) recommends doxycycline or azithromycin as first-choice antibiotic for the treatment of genital chlamydia. These medications are very effective for both acute and persistent infections.
Important note: To avoid reinfection, persons with chlamydia should abstain from sexual activity until they and their sex partners have completed the treatment.
- High efficacy. Doxycycline is an old proven and reliable treatment with cure rates exceeding 90%2. Most new treatments are compared against this antibiotic.
- Doxycycline may be more effective than azithromycin for symptomatic urethral infection in men2.
- Doxycycline is less expensive than azithromycin. It has been used extensively for a longer period.
- Doxycycline is contraindicated during pregnancy and breastfeeding.
- Its dosage regimen is less convenient than that of azithromycin.
Doxycycline dosage: 100 mg orally twice a day for 7 days for urogenital chlamydial infection (chlamydial urethritis and cervicitis).
Learn about doxycycline vs azithromycin for chlamydia
Azithromycin (Zithromax®, Z-pak®)
- Highly effective. Azithromycin has virtually revolutionized the treatment of chlamydial infections. It is one of the most widely studied antibiotics for chlamydia and provides a cure rate of 96% 6.
- Important advantage of azithromycin is that it works after taking a single dose. But you'll need to wait seven days after taking the medicine before having sex again.
- Chronic persistent chlamydia
Azithromycin is particularly effective for chronic persistent genital chlamydia.
- Chlamydia during pregnancy
Azithromycin is also recommended as a first-line treatment for genital chlamydial infection during pregnancy. There is evidence supporting azithromycin as safe and effective in pregnant women4.
- Chlamydia associated with infertility
New research from the Safdarjung Hospital7 suggests that azithromycin with its broader immunomodulatory effects may be preferable to doxycycline for the treatment of recurrent C. trachomatis infection associated with infertility.
- Rectal Chlamydia infection
According to the latest evidence9, a single dose azithromycin therapy for rectal chlamydia often results in treatment failure. Therefore doxycycline may be more preferable choice for rectal infection.
Azithromycin dosage: 1 g orally in a single dose.
Alternative dosage regimen: 500 mg in a single dose on day 1 followed by 250 mg once daily for 2 days5.
* Note: According to 2016 report azithromycin treatment failure for C. trachomatis is about 6.2-12.8%12.
- Erythromycin is a second-line treatment choice.
- Low cost.
- Erythromycin can be used in pregnancy. But erythromycin estolate is contraindicated during pregnancy.
- Erythromycin is less efficacious than other recommended antibiotics 11.
- Lengthy dosing (four times daily).
- Commonly causes gastrointestinal disturbances, which often lead to discontinuation.
Erythromycin dosage: 500 mg orally 4 times a day 7 days.
Erythromycin ethylsuccinate dosage: 800 mg orally 4 times a day 7 days.
- Effective alternative antibiotic.
- Levofloxacin has been successfully evaluated for treatment of chlamydia infection in clinical trials8.
- Because its pharmacology and in vitro microbiologic activity are similar to that of ofloxacin, levofloxacin may be substituted in doses of 500 mg once a day for 7 days.
- Contraindicated in pregnancy.
- No essential advantages over doxycycline or azithromycin.
Levofloxacin dosage: 500 mg orally for 7 days.
- Effective alternative medication.
- Similar in efficacy to doxycycline and azithromycin (cure rate about 95%).
- Good side-effect profile.
- Ofloxacin cannot be taken in pregnancy.
Ofloxacin dosage: 300 mg orally twice a day for 7 days.
Other fluoroquinolones, in particular ciprofloxacin (Cipro®), are NOT sufficiently effective against Chlamydia trachomatis.
According to the 2015 CDC Guidelines10 amoxicillin is now considered only an alternative treatment for Chlamydia infection during pregnancy. However, amoxicillin is not the best antibiotic for eradication of Chlamydia in other categories of people.
Amoxicillin dosage: 500 mg orally 3 times a day for 7 days.
Chlamydia can be transmitted during vaginal, anal, and, although less likely, oral sex. Genital infection can also be passed from an infected mother to the baby during vaginal childbirth. The bacteria also can infect the throat during oral sexual contact with an infected partner.
Chlamydia can be transmitted even if the penis or tongue does not enter the vagina, mouth, or rectum. Using latex condoms consistently and correctly - from the very beginning of sexual contact until there is no longer skin contact - reduces the risk of transmission of chlamydia.
Chlamydia is known as an asymptomatic or "silent" disease because about 75% of infected women and about 50% of infected men have no symptoms until the infection has become advanced. If symptoms do occur, they usually appear within 1 to 3 weeks after exposure.
In women, C. trachomatis initially infect the cervix and the urethra (urine canal). Infected women may have an abnormal vaginal discharge, burning sensation when urinating, pain during intercourse, lower abdominal pain. When the infection spreads from the cervix to the fallopian tubes, some women still have no any warning symptoms. Chlamydial infection of the cervix can spread to the rectum.
Infected men may have a discharge from the penis, painful urination, burning and itching around the opening of the penis. Pain and swelling in the testicles are uncommon.
Persons who have receptive anal intercourse may acquire chlamydial infection in the rectum, which can cause rectal pain, discharge, or bleeding. Chlamydia can also be found in the throats of women and men having oral sex with an infected partner.
Even though symptoms of chlamydia are usually minimal, severe complications can occur. Untreated genital chlamydia can progress to serious health problems with long-term consequences.
In women, untreated infection can spread into the uterus or fallopian tubes and cause pelvic inflammatory disease (PID). This happens in up to 40% of women with advanced chlamydia. PID can cause permanent damage to the fallopian tubes, uterus, and surrounding tissues. The damage can lead to chronic pelvic pain, infertility, and potentially fatal ectopic pregnancy (pregnancy outside the uterus).
Untreated chlamydia in men typically causes infection of the urethra, the tube that carries urine from the body. Infection sometimes spreads to the tube that carries sperm from the testis, causing epididymitis (inflammation of the reproductive area near the testicles). This may cause pain, fever, and even infertility.
Rarely, genital chlamydial infection can cause reactive arthritis (Reiter's syndrome) that can be accompanied by skin and mucous membranes lesions, inflammation of the eye and urethra.
In pregnant women, chlamydia infections may lead to premature delivery. Babies born to infected mothers can get eyes infections (conjunctivitis or pinkeye), as well as pneumonia. Both diseases can be treated with antibiotics.
- 1. Sexually Transmitted Diseases Treatment Guidelines 2015 Centers for Disease Control and Prevention
- 2. Kong FY, Tabrizi SN, Law M, Vodstrcil LA, Chen M, Fairley CK, Guy R, Bradshaw C, Hocking JS. Azithromycin versus doxycycline for the treatment of genital chlamydia infection: a meta-analysis of randomized controlled trials. Clin Infect Dis. 2014 Jul 15;59(2):193-205. PubMed
- 3. Chlamydial Infections: Urethritis and Cervicitis STD Treatment Guidelines 2015 Centers for Disease Control and Prevention
- 4. Rahangdale L, Guerry S, Bauer HM, et al. An observational cohort study of Chlamydia trachomatis treatment in pregnancy. Sex Transm Dis. 2006;33(2):106-110.
- 5. Whatley JD, Thin RN, Mumtaz G, Ridgway GL. Azithromycin vs doxycycline in the treatment of non-gonococcal urethritis. 1991 Jul-Aug;2(4):248-51.
- 6. Miller JM. Efficacy and Tolerance of Single-dose Azithromycin for Treatment of Chlamydial Cervicitis During Pregnancy. Infect Dis Obstet Gynecol. 1995;3(5):189-92
- 7. Srivastava P, Bhengraj AR, Jha HC, Vardhan H, Jha R, Singh LC, Salhan S, Mittal A. Differing effects of azithromycin and doxycycline on cytokines in cells from Chlamydia trachomatis-infected women. DNA Cell Biol. 2012 Mar.
- 8. Mikamo H, Yamagishi Y, Takahashi K, et al. Clinical study of levofloxacin 500 mg qd in the treatment of cervicitis and intrauterine infections caused by Chlamydia trachomatis. Jpn J Antibiot. 2011 Aug;64(4):217-29.
- 9. Kong FY, Tabrizi SN, Fairley CK, Vodstrcil LA, Huston WM, Chen M, Bradshaw C, Hocking JS. The efficacy of azithromycin and doxycycline for the treatment of rectal chlamydia infection: a systematic review and meta-analysis. J Antimicrob Chemother. 2015 May;70(5):1290-7. PubMed
- 10. 2015 Sexually Transmitted Diseases Treatment Guidelines: Chlamydial Infections. CDC
- 11. Edwards MS, Newman RB, Carter SG, Leboeuf FW, Menard MK, Rainwater KP. Randomized Clinical Trial of Azithromycin vs. Erythromycin for the Treatment of Chlamydia Cervicitis in Pregnancy. Infect Dis Obstet Gynecol. 1996;4(6):333-7. PubMed
- 12. Kissinger PJ, White S, Manhart LE, et al. Azithromycin Treatment Failure for Chlamydia trachomatis Among Heterosexual Men With Nongonococcal Urethritis. Sex Transm Dis. 2016 Oct;43(10):599-602. PubMed
Originally published: January 20, 2009
Last updated: August 14, 2018