Azithromycin to cure chlamydia: How much and how long?
After taking two 500mg of antibiotics for chlamydia how long does it take for the infection to clear?
Medically reviewed by Carmen Fookes, BPharm. Last updated on Nov 30, 2020.
A single dose of azithromycin 1 gram orally will cure genital chlamydia according to the CDC Guidelines for Sexually Transmitted Diseases, released in 2015, but still considered current. This is usually taken as four 250mg or two 500mg tablets of azithromycin in a single dose.
The dose is the same for adults and children over the age of eight years or weighing at least 45kg. The dose is also the same for people with HIV and those without HIV. The CDC recommends this dose to treat the following types of chlamydia:
- Urogenital (affect both the urinary and genital tracts)
- Anogenital (affecting both the anus and genital tracts) (Note the WHO STI guidelines prefer doxycycline over azithromycin for anorectal chlamydial infection)
- Oropharyngeal (the area or the throat at the back of the mouth that includes the back third of the tongue, the soft palate, the side and back walls of the throat, and the tonsils).
After taking azithromycin 1 gram as a single dose, sexually active people should abstain from sexual activity for 7 days to prevent spreading the infection to partners.
All sexual partners of the person with chlamydia should also be treated with azithromycin 1 gram orally as a single dose. Depending on state laws, which can vary, this may be done as expedited therapy (based on a clinical evaluation but not necessarily waiting for laboratory confirmation) if a doctor is concerned that the partner will not be properly evaluated or treated.
A follow-up evaluation can be done in 3 to 4 weeks to test for treatment failure or reinfection.
Lymphogranuloma venereum (LGV), is a chlamydial disease caused by 3 unique strains of Chlamydia trachomatis and characterized by a small, often asymptomatic skin lesion, followed by swollen lymph glands in the groin or pelvis. If LGV is acquired by anal sex it may manifest as severe proctitis.
For LGV the WHO Sexually Transmitted Infection guidelines prefer doxycycline 100 mg orally twice daily for 21 days over azithromycin 1 gram orally, weekly for 3 weeks.
What is the dosage of azithromycin for chlamydia?
The recommended dosage of azithromycin for chlamydia is 1 gram as a single dose. This dose may be taken morning or night and can be taken with or without food. Another name for azithromycin is Zithromax.
If you have taken your dose of azithromycin on an empty stomach and your stomach has become a bit upset or you feel sick, it is Ok to eat some food, which may help to settle it.
A 500mg dose of azithromycin is not recommended by guidelines to cure chlamydia. There is also a chance it may increase the risk of C. trachomatis bacteria becoming resistant to it. If you have only taken or only been prescribed a 500mg dose of azithromycin, you need to return to your doctor to get a 1 gram dose prescribed. You should never share your dose of azithromycin with another person.
Can you drink alcohol while taking azithromycin for chlamydia?
Yes, you may drink a small amount of alcohol while you are taking azithromycin but there is a chance large amounts of alcohol may increase the gastrointestinal side effects of azithromycin, such as nausea, diarrhea, vomiting, abdominal pain, dyspepsia, or flatulence. Too much alcohol with azithromycin may also give you a headache.
Because azithromycin is usually taken as a one-off dose, drinking alcohol is unlikely to stop azithromycin from curing chlamydia.
Does azithromycin cure chlamydia?
Cure rates of 97% were reported in an analysis of 12 randomized clinical trials that investigated the use of azithromycin 1 gram for the treatment of chlamydia. That means for every 100 people with chlamydia who take azithromycin, 97 will be cured and 3 will not be cured.
This relies on the person with chlamydia taking azithromycin exactly as directed and not sharing the medication with anyone. Any sexual partners must be also treated.
Although azithromycin cures chlamydia in most people, it will not repair any permanent damage done to tissues by the disease.
If you have been symptomatic with chlamydia before treatment and your symptoms continue for more than a few days after receiving treatment, then ask to be re-evaluated by your health care provider.
Unfortunately, repeat infection with chlamydia is common. This means that even though azithromycin has cured your current infection with chlamydia, this does not mean you will not get chlamydia again. If your sexual partners have not been appropriately treated, you are at high-risk for reinfection. Having chlamydia multiple times puts women at high risk of fertility problems, ectopic pregnancy, and pelvic inflammatory disease. Infants born to mothers who are infected with chlamydia may develop chlamydial conjunctivitis and/or pneumonia. Chlamydial infection in infants can be treated with antibiotics.
Three months after you have finished a course of azithromycin you should get retested for chlamydia. This is regardless of whether you believe that your sexual partners were successfully treated.
How should azithromycin be taken for chlamydia?
Azithromycin tablets may be taken either with food or without food. If you have taken your dose of azithromycin on an empty stomach and you develop stomach pain or feel sick, it is OK to eat some food, which may help to settle it.
How long does it take for azithromycin to cure chlamydia?
It takes approximately one week (seven days) for azithromycin to cure chlamydia.
Do not have sex for seven days after taking your single dose of azithromycin, or you may infect your sexual partner with chlamydia.
Is azithromycin better than doxycycline at curing chlamydia?
STD guidelines still favor azithromycin over doxycycline for the treatment of chlamydia. This is because of the following reasons:
- Cure rates of azithromycin and doxycycline are similar, 97% and 98-100% respectively, according to a meta-analysis of 12 trials.
- Azithromycin is given as a single dose, doxycycline needs to be given for seven days, either as a once-daily or twice-daily dose.
- The dose of azithromycin can be easily supervised if need be; it is much harder to supervise seven days of once daily or twice daily doxycycline treatment
- People are more likely to take a single dose of azithromycin than finish a seven-day course of doxycycline.
Recently, some reports have suggested that doxycycline may be more effective than azithromycin, particularly when medication adherence can be assured. There is also some concern that azithromycin may not be as effective for anogenital (rectal and genital) chlamydial infections.
Is treatment always necessary for chlamydia?
Yes, treatment is necessary for chlamydia, particularly in women of childbearing age, because it reduces the risk of chlamydia-associated ectopic pregnancy, fertility problems, and the transmission of chlamydia to neonates during birth. In women, of all ages, chlamydia treatment reduces the risk of pelvic inflammatory disease.
In men, treatment for chlamydia stops them from infecting or reinfecting sexual partners with the bacteria.
Treat any person testing positive for chlamydia with a recommended course of antibiotics promptly. Delays in treatment have been associated with complications, such as pelvic inflammatory disease.
How is chlamydia treated?
The following are the recommended treatment regimens for chlamydia according to the Guidelines for Sexually Transmitted Diseases, released in 2015, but still considered current. Only one regimen should be chosen.
- Azithromycin 1 gram orally as a single dose
- Doxycycline 100 mg orally twice a day for 7 days
- Doxycycline 200mg orally once daily for 7 days (Doryx).
Alternative regimens include:
- Erythromycin base 500 mg orally four times a day for 7 days
- Erythromycin ethylsuccinate 800 mg orally four times a day for 7 days
- Levofloxacin 500 mg orally once daily for 7 days
- Ofloxacin 300 mg orally twice a day for 7 days.
What is chlamydia?
Chlamydia is the most common infection reported in the United States, with the highest prevalence in women aged less than 25 years, although it can occur in both men and women and at all ages. It is caused by bacteria called Chlamydia trachomatis, and if left untreated, can cause pelvic inflammatory disease, ectopic pregnancy, and infertility in women.
What are the symptoms of chlamydia?
Many people with chlamydia have no symptoms at all, and their infection is only picked up with a screening test.
Guidelines currently recommend that all women under the age of 25 get screened for chlamydia every year. Older women at increased risk for an infection, such as those with a new sex partner, more than one sex partner, a sex partner with concurrent partners, or a sex partner who has a sexually transmitted infection, should also be screen regularly.
Although routine screening for chlamydia in young men is not currently recommended, it should be considered in populations with a high prevalence of chlamydia (such as adolescent clinics, correctional facilities, and STD clinics) or those at high risk for chlamydia (such as men who have sex with men).
Some people may have symptoms.
Women may notice an unusual vaginal discharge or problems when urinating (peeing), such as pain or burning, an increased need to urinate (pee); pain during sex; bleeding between periods or after sex; lower abdominal (stomach), or pelvic (hip) pain or cramps or.
Men may notice a discharge from their penis, pain or discomfort while urinating (peeing), or pain or swelling in their testicles.
How is chlamydia diagnosed?
Chlamydia can be diagnosed with either a first-catch urine test or a swab collected from the endocervix or vagina in women, or a first-catch urine test or a swab collected from the urethra in men.
Self-collected vaginal swab testing is available and many women find this screening strategy highly acceptable.
- Geisler WM, Uniyal A, Lee JY, et al. Azithromycin versus Doxycycline for Urogenital Chlamydia trachomatis Infection. N Engl J Med. 2015;373(26):2512-2521. doi:10.1056/NEJMoa1502599
- Workowski, K, Bolan G. U.S. Department of Health and Human Services. Sexually Transmitted Diseases Treatment Guidelines, 2015. Morbidity and Mortality Weekly Report. June 05, 2015:64(3)
- WHO Guidelines for the Treatment of Chlamydia trachomatis. Geneva: World Health Organization; 2016. 4, RECOMMENDATIONS FOR TREATMENT OF CHLAMYDIAL INFECTIONS. Available from: https://www.ncbi.nlm.nih.gov/books/NBK379708/
- Chlamydia Treatment and Care. Centers for Disease Control and Prevention (CDC) https://www.cdc.gov/std/chlamydia/treatment.htm
- Chlamydia Treatment Information Sheet. Wisconsin Department of Health Services. https://www.dhs.wisconsin.gov/publications/p0/p00197.pdf
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