Over the counter antibiotics for chlamydia and gonorrhea

Over the counter medications cannot be used to treat chlamydia. Effective treatment for chlamydia relies on antibiotics, which are only available with a prescription.

Over-use of antibiotics in a population can lead to bacteria, including Chlamydia trachomatis, becoming resistant to the medication. In an attempt to limit the development of this problem, antibiotics are generally only available with a doctor’s prescription.

If they were available over the counter, they would likely be used much more frequently, including in cases where a person did not in fact have an infection that could be treated with an antibiotic — leading to the development of resistant strains. In fact, even with antibiotics only available of prescription, experts believe that doctors currently prescribe antibiotics far too readily, contributing to the problem of resistance. The only antibiotics available without prescription are topical (for application to the skin).

Treatment for chlamydia is quite simple but you will need to see a healthcare professional to obtain it. The Centers for Disease Control and Prevention recommends a range of antibiotics — in most cases, either azithromycin (a single dose of a tablet) or doxycycline (a tablet twice a day for seven days).

You also need to see a healthcare professional to have your condition accurately diagnosed — the symptoms of several other sexually transmitted infections are quite similar to those of chlamydia.


More on Chlamydia at TheBody.com

To find out more about chlamydia and its treatment, we recommend the following articles:

  • Chlamydia
  • Chlamydia’s Quick Cure
  • Pointers on Chlamydia Prevention and Care for People With HIV

In addition, our Q&A experts sometimes address questions about chlamydia in our “Ask the Experts” forums. Here are some of those questions and our experts’ responses:

  • Over the counter
    What over the counter drugs if any are effective against chlamydia?
  • How can I get rid of resistant Chlamydia?
    I have read online of resistant forms of Chlamydia. Are resistant forms impossible to get rid of? Should I ask my doctor about azithromycin?

Azithromycin Prescribed Online

  • Request azithromycin prescription online
  • Same day prescriptions available
  • Affordable consultations

Azithromycin – An Overview

Azithromycin is a type of antibiotic that is used in the treatment or prevention of infections that are strongly suspected or proven to be caused by bacteria susceptible to the medication. Push Health can connect people who think they need an azithromycin prescription with licensed medical providers who can prescribe azithromycin if it is safe and appropriate to do so.

What Is Azithromycin Used For?

Azithromycin, the active ingredient found in the commonly used form Z-pak, is a macrolide antibiotic like clarithromycin and erythromycin. Azithromycin is indicated in the treatment of specific cases of COPD exacerbations with bronchitis, bacterial sinusitis, community-acquired pneumonia, pharyngitis and skin infections. Azithromycin for chlamydia urethritis is also sometimes used, especially with infections identified by STD testing. Azithromycin works by binding to a ribosomal subunit in a bacteria, thereby blocking protein synthesis. Bacteria that are resistant to azithromycin tend to have modifications in their 23S rRNA. Azithromycin is similar to the antibiotic erythromycin.

Azithromycin – Dosage and Metabolism

Azithromycin is typically incorporated into branded versions of the antibiotic as azithromycin 250 mg and Azithromycin 500 mg. Two azithromycin 250 mg are considered to be bioequivalent to azithromycin 500 mg and no dosage adjustments are generally made based on gender. The terminal elimination half-life of azithromycin after an azithromycin 500 mg dose is approximately 68 hours. Azithromycin’s antimicrobial properties are thought to be related to the pH. Azithromycin is similar to erythromycin except that it has a slightly different chemical structure. Azithromycin differs in structure from amoxicillin and is used to treat a different range of infections.

Azithromycin – Cost & Prescription

Azithromycin, in its branded form, is also available in a convenient blister pack known as a Z-Pak. On a per pill basis, azithromycin is moderately affordable at under $1 per pill. Because azithromycin regimens are generally short, the overall cost for an azithromycin prescription is relatively affordable. Azithromycin is a prescription medication and one cannot get it over-the-counter (OTC) at pharmacies in the US. Azithromycin coupons may also be available at times to reduce the cost of the medication even more.

Can I Buy Azithromycin Online?

Azithromycin is a prescription medication and one cannot simply buy azithromycin online legally. Instead, one must first get a prescription azithromycin from a licensed medical provider before being able to obtain the medication from a pharmacy. Push Health can connect people who need an azithromycin prescription with licensed providers who can prescribe azithromycin if it is safe and appropriate to do so.

Azithromycin – Side Effects

Azithromycin, like most medications, can cause side effects. Side effects from azithromycin use include, but not limited to, diarrhea, nausea and abdominal pain. Other azithromycin side effects include palpitations, vomiting, dyspepsia, fatigue, rash, and arrhythmias. People with a past hypersensitivity or allergic reaction to azithromycin or other macrolide antibiotics should not use azithromycin. Azithromycin and alcohol should not be used at the same time. Concerns or questions about side effects related to azithromycin use should be directed to one’s medical provider and pharmacist.

More Azithromycin Information

Last updated November 18, 2019. Given the evolving nature of medicine and science, this information might not be accurate and should not be construed as medical advice or diagnosis / treatment recommendations. Please consult a licensed medical provider if you have additional questions.

What Conditions does Rocephin Vial Treat?

  • blood infection caused by Streptococcus bacteria
  • acute gonorrhea of the urethra
  • bacterial meningitis caused by Streptococcus
  • pneumonia caused by gram-negative bacteria
  • urinary tract infection due to E. coli bacteria
  • PID with gonorrhea
  • skin infection due to E. coli bacteria
  • skin tissue infection due to Peptostreptococcus bacteria
  • infectious arthritis caused by Haemophilus bacteria
  • joint infection caused by Klebsiella species bacteria
  • bone infection due to Streptococcus bacteria
  • bone infection caused by Haemophilus bacteria
  • infection of bone
  • treatment to prevent meningococcal meningitis
  • Escherichia coli bacteria in the blood
  • a systemic inflammatory response called sepsis due to an infection with bacteria
  • gonorrhea infection of the throat
  • a brain infection called Gonococcal meningitis
  • gonococcal endocarditis
  • gonorrhea which is widely distributed throughout the body
  • chancroid
  • bacterial pneumonia caused by Klebsiella
  • a lower respiratory infection
  • infection of a joint caused by Streptococcus bacteria
  • blood infection caused by Staphylococcus bacteria
  • acute gonorrhea of the cervix
  • conjunctivitis caused by gonorrhea
  • bacterial meningitis caused by Staphylococcus
  • inflammation of the endometrium
  • skin infection due to Streptococcus pyogenes bacteria
  • skin infection due to Proteus bacteria
  • bacterial meningitis
  • bacterial meningitis caused by haemophilus influenzae
  • pneumonia caused by the bacteria Enterobacter
  • infection within the abdomen
  • infection of a woman’s reproductive organs
  • skin infection due to Klebsiella bacteria
  • infection of a joint
  • blood poisoning caused by Haemophilus species bacteria
  • acute gonorrhea of the lower genital and urinary organs
  • meningitis caused by Klebsiella
  • pneumonia due to the bacteria Haemophilus parainfluenzae
  • bacterial pneumonia caused by Streptococcus
  • pneumonia caused by the bacteria Serratia
  • urinary tract infection caused by Klebsiella bacteria
  • infection of the urinary tract from Proteus bacteria
  • skin infection due to Enterobacter bacteria
  • bone infection caused by Klebsiella pneumoniae bacteria
  • bone infection due to Proteus mirabilis bacteria
  • bone infection caused by E. coli
  • bone infection caused by Enterobacter
  • infection caused by Haemophilus influenzae type B bacteria
  • acute gonorrhea of the lining of the uterus
  • gonococcal arthritis
  • bacterial meningitis caused by Pneumococcus
  • a bacterial infection of the middle ear
  • bacterial pneumonia caused by Haemophilus influenzae
  • pneumonia caused by Proteus bacteria
  • Klebsiella pneumoniae infection of abdominal cavity lining
  • complicated urinary tract infection from Enterobacter
  • an infection of the female reproductive organs called pelvic inflammatory disease
  • an infection of the skin and the tissue below the skin
  • infection of a joint caused by Escherichia coli bacteria
  • infection of a joint caused by Proteus bacteria
  • bacterial urinary tract infection
  • meningococcal meningitis
  • infection of the blood by Klebsiella pneumoniae bacteria
  • a systemic inflammatory response called sepsis due to an infection with Salmonella bacteria
  • meningitis caused by E. coli bacteria
  • pneumonia caused by E. coli bacteria
  • joint infection caused by Enterobacter species bacteria
  • gonorrhea of the rectum
  • bacterial pneumonia caused by Staphylococcus
  • pneumonia caused by bacteria
  • E. coli bacteria infection of abdominal cavity lining
  • peritonitis caused by Peptostreptococcus bacteria
  • skin infection due to Serratia bacteria
  • skin infection caused by Morganella morganii
  • bacteria causing an infection in the joints
  • infectious arthritis caused by Escherichia coli bacteria
  • prevention of perioperative infection
  • Lyme disease
  • pediatric fever without a source
  • infection caused by Yersinia pseudotuberculosis bacteria
  • treatment to prevent bacterial infection of a heart valve
  • lyme disease of the central nervous system
  • arthritis in Lyme disease
  • inflammation of heart due to Lyme disease
  • bacterial infection of heart valve due to Enterococcus
  • bacterial infection of heart valve due to Streptococcus
  • heart valve infection caused by Haemophilus
  • infection by Yersinia enterocolitica

What Are the Treatments for Chlamydia?

If you are diagnosed with chlamydia, your doctor will prescribe oral antibiotics. A single dose of azithromycin or taking doxycycline twice daily for 7 to 14 days are the most common treatments and are the same for those with or without HIV.

With treatment, the infection should clear up in about a week. Do not have sex for at least 7 days until you have taken all of your medication, and do not stop taking the antibiotics even if you feel better.

Your doctor will also recommend that your partner(s) be treated as well to prevent reinfection and further spread of the disease.

Women with serious infections, such as pelvic inflammatory disease, may require a longer course of antibiotics or hospitalization for intravenous antibiotics. Some severe pelvic infections may require surgery in addition to antibiotic therapy.

Make sure you get retested after three months to be certain the infection is gone. Do this even if your partner has been treated and appears to be infection free.

Chlamydia Treatment and Care

Chlamydia is easily cured but can make pregnancy difficult if left untreated.

What is the treatment for chlamydia?

Chlamydia can be easily cured with antibiotics. HIV-positive persons with chlamydia should receive the same treatment as those who are HIV-negative.

Persons with chlamydia should abstain from sexual activity for 7 days after single dose antibiotics or until completion of a 7-day course of antibiotics, to prevent spreading the infection to partners. It is important to take all of the medication prescribed to cure chlamydia. Medication for chlamydia should not be shared with anyone. Although medication will stop the infection, it will not repair any permanent damage done by the disease. If a person’s symptoms continue for more than a few days after receiving treatment, he or she should return to a health care provider to be reevaluated.

Repeat infection with chlamydia is common. Women whose sex partners have not been appropriately treated are at high risk for re-infection. Having multiple chlamydial infections increases a woman’s risk of serious reproductive health complications, including pelvic inflammatory disease and ectopic pregnancy. Women and men with chlamydia should be retested about three months after treatment of an initial infection, regardless of whether they believe that their sex partners were successfully treated.

Infants infected with chlamydia may develop ophthalmia neonatorum (conjunctivitis) and/or pneumonia. Chlamydial infection in infants can be treated with antibiotics.

Treatment Guidelines and Updates

  • 2015 STD Treatment Guidelines – Chlamydial Infections (June 4, 2015)

Resources for Clinicians

  • Chlamydia Self-Study ModuleExternal – An online learning experience that helps users learn how to manage chlamydia. It is continuously updated and integrates the most recent STD Treatment Guidelines. Free CME/CNE available. (November 1, 2017)
  • Chlamydia trachomatisExternal Genital Infection External– Journal of Infectious Diseases Supplement, 15 June 2010 (May 21, 2010)
  • Clinic-Based Testing for Rectal and Pharyngeal Neisseria gonorrhoeae and Chlamydia trachomatis Infections MMWR July 10, 2009 (July 10, 2009)
  • Expedited Partner Therapy (EPT)

Related Content


Who has chlamydia?

A lot of people have chlamydia – as many as 1 in 10 young women test positive for it. In 2016, over 1 and a half million cases of chlamydia were reported to the CDC in the US. In California alone, there were almost 200,000 reported cases of chlamydia in 2016.

How do you get chlamydia?

You can get chlamydia from any type of sex. Chlamydia infections like to live in the type of tissue that lines the openings of your body – like the vagina, the urethra, the rectum, or the throat. It can get passed between two people any time these tissues come together – which happens most often during unprotected vaginal or anal sex. It’s less common – but not impossible – to get chlamydia from oral sex.

How do you know you have chlamydia? What are chlamydia symptoms?

Most people who have it don’t know because they don’t have symptoms. Among young women, chlamydia is sometimes called the “Silent Epidemic” because it causes so much damage in so many people without even showing any symptoms. A few people might have a thick yellow or clear discharge from the penis or vagina, pain or burning when they pee, or pain or bleeding during sex.

How do you test for chlamydia?

Clinicians can do a simple and painless urine test to find out if you have chlamydia. They may also collect a swab sample from the vagina, cervix, urethra or rectum during a physical exam.

Can you get rid of chlamydia?

Chlamydia can be cured with antibiotics. The best way to cure chlamydia and keep from infecting your partners, is to avoid sex for seven (7) days, until the antibiotics have done their job. If you do end up having sex while the antibiotics are still working it is really important to use a condom or else it is likely the medicine you took won’t work. If you got medication to take at home make sure you take all of the pills, even if you start to feel better – otherwise the infection might not go away completely.

How can you protect yourself from getting chlamydia?

The only method that is 100% effective in preventing STDs is abstinence, but if you’re sexually active, the best way to avoid chlamydia is to be mutually monogamous with someone who has tested negative for chlamydia. Condoms give good protection against chlamydia during vaginal sex and during oral sex on a male. It’s important for both partners to get tested because it’s easy to get re-infected if one partner still has it. If you test positive for chlamydia, get tested again three (3) months later to make sure you don’t have it again. If you’re sexually active and under 25, you should get tested for chlamydia every year – better safe than sorry.

For protection against chlamydia during oral sex on a female, you can use a dental dam as a barrier between the mouth and vulva. A dental dam is a thin square of latex that is placed over a woman’s vulva before her partner performs oral sex on her and acts as a barrier between the vulva and the mouth. They are sold in some stores, but you can make your own dental dam using a latex glove or a male condom. For protection against Chlamydia during any type of anal sex (rimming, penetration, etc.), you can use a female condom.

What’s the worst that could happen?

For women, a chlamydia infection can lead to Pelvic Inflammatory Disease (PID), an infection of parts of the reproductive system like the uterus, ovaries, and fallopian tubes. That means if you have chlamydia and you don’t get it treated, you might not be able to have babies if and when you want to. PID can also lead to problems like chronic pelvic pain or ectopic pregnancy.

In men, untreated chlamydia may spread to the testicles, causing pain, and in rare cases, infertility.

Chlamydia infection also increases your likelihood of getting HIV. Pregnant women who have chlamydia can pass it on to their babies during birth, which could cause blindness or lung damage.

Chlamydial Infections

Special Considerations


Doxycycline is contraindicated in the second and third trimesters of pregnancy. Human data suggest ofloxacin and levofloxacin present a low risk to the fetus during pregnancy, with a potential for toxicity during breastfeeding; however, data from animal studies raise concerns about cartilage damage to neonates (317). Thus, alternative drugs should be used to treat chlamydia in pregnancy. Clinical experience and published studies suggest that azithromycin is safe and effective (523-525). Test-of-cure to document chlamydial eradication (preferably by NAAT) 3–4 weeks after completion of therapy is recommended because severe sequelae can occur in mothers and neonates if the infection persists. In addition, all pregnant women who have chlamydial infection diagnosed should be retested 3 months after treatment. Detection of C. trachomatis infection at repeat screening during the third semester is not uncommon in adolescent and young adult women, including in those without C. trachomatis detected at the time of initial prenatal screening (526,527). Women aged <25 years and those at increased risk for chlamydia (e.g., those who have 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 be rescreened during the third trimester to prevent maternal postnatal complications and chlamydial infection in the infant (108).

Recommended Regimens
  • Azithromycin 1 g orally in a single dose
Alternative Regimens
  • Amoxicillin 500 mg orally three times a day for 7 days
  • Erythromycin base 500 mg orally four times a day for 7 days
  • Erythromycin base 250 mg orally four times a day for 14 days
  • Erythromycin ethylsuccinate 800 mg orally four times a day for 7 days
  • Erythromycin ethylsuccinate 400 mg orally four times a day for 14 days

Because of concerns about chlamydia persistence following exposure to penicillin-class antibiotics that has been demonstrated in animal and in vitro studies, amoxicillin is now considered an alternative therapy for C. trachomatis in pregnant women (528,529). The frequent gastrointestinal side effects associated with erythromycin can result in nonadherence with these alternative regimens. The lower dose 14-day erythromycin regimens can be considered if gastrointestinal tolerance is a concern. Erythromycin estolate is contraindicated during pregnancy because of drug-related hepatotoxicity.

HIV Infection

Persons who have chlamydia and HIV infection should receive the same treatment regimen as those who do not have HIV infection. For more information, see Chlamydia, Treatment.

Top of Page

Chlamydial Infections Among Neonates

Prenatal screening and treatment of pregnant women is the best method for preventing chlamydial infection among neonates. C. trachomatis infection of neonates results from perinatal exposure to the mother’s infected cervix. Although the efficacy of neonatal ocular prophylaxis with erythromycin ophthalmic ointments to prevent chlamydia ophthalmia is not clear, ocular prophylaxis with these agents prevents gonococcal ophthalmia and therefore should be administered (see Ophthalmia Neonatorum Caused by N. gonnorrhoeae).

Initial C. trachomatis neonatal infection involves the mucous membranes of the eye, oropharynx, urogenital tract, and rectum, although infection might be asymptomatic in these locations. Instead, C. trachomatis infection in neonates is most frequently recognized by conjunctivitis that develops 5–12 days after birth. C. trachomatis also can cause a subacute, afebrile pneumonia with onset at ages 1–3 months. Although C. trachomatis has been the most frequent identifiable infectious cause of ophthalmia neonatorum, neonatal chlamydial infections (including ophthalmia and pneumonia) have occurred less frequently since the institution of widespread prenatal screening and treatment of pregnant women.

Ophthalmia Neonatorum Caused by C. trachomatis

A chlamydial etiology should be considered for all infants aged ≤30 days that have conjunctivitis, especially if the mother has a history of chlamydia infection. These infants should receive evaluation and appropriate care and treatment.

Sensitive and specific methods used to diagnose chlamydial ophthalmia in the neonate include both tissue culture and nonculture tests (e.g., direct fluorescence antibody tests and NAAT). DFA is the only nonculture FDA-cleared test for the detection of chlamydia from conjunctival swabs; NAATs are not FDA-cleared for the detection of chlamydia from conjunctival swabs, and clinical laboratories must verify the procedure according to CLIA regulations. Specimens for culture isolation and nonculture tests should be obtained from the everted eyelid using a dacron-tipped swab or the swab specified by the manufacturer’s test kit; for culture and DFA, specimens must contain conjunctival cells, not exudate alone. Ocular specimens from neonates being evaluated for chlamydial conjunctivitis also should be tested for N. gonorrhoeae (see Ophthalmia Neonatorum Caused by N. gonnorrhoeae).

Treatment of Ophthalmia Neonatorum
Recommended Regimen
  • Erythromycin base or ethylsuccinate 50 mg/kg/day orally divided into 4 doses daily for 14 days*
Alternative Regimen
  • Azithromycin suspension, 20 mg/kg/day orally, 1 dose daily for 3 days*

*An association between oral erythromycin and azithromycin and infantile hypertrophic pyloric stenosis (IHPS) has been reported in infants aged <6 weeks. Infants treated with either of these antimicrobials should be followed for signs and symptoms of IHPS.

Although data on the use of azithromycin for the treatment of neonatal chlamydia infection are limited, available data suggest a short course of therapy might be effective (530). Topical antibiotic therapy alone is inadequate for treatment for ophthalmia neonatorum caused by chlamydia and is unnecessary when systemic treatment is administered.

Because the efficacy of erythromycin treatment for ophthalmia neonatorum is approximately 80%, a second course of therapy might be required (531). Data on the efficacy of azithromycin for ophthalmia neonatorum are limited. Therefore, follow-up of infants is recommended to determine whether initial treatment was effective. The possibility of concomitant chlamydial pneumonia should be considered (see Infant Pneumonia Caused by C. trachomatis).

Management of Mothers and Their Sex Partners

Mothers of infants who have ophthalmia caused by chlamydia and the sex partners of these women should be evaluated and presumptively treated for chlamydia. For more information, see Chlamydial Infection in Adolescents and Adults.

Infant Pneumonia Caused by C. trachomatis

Chlamydia pneumonia in infants typically occurs at 1–3 months and is a subacute pneumonia. Characteristic signs of chlamydial pneumonia in infants include 1) a repetitive staccato cough with tachypnea and 2) hyperinflation and bilateral diffuse infiltrates on a chest radiograph. In addition, peripheral eosinophilia (≥400 cells/mm3) occurs frequently. Because clinical presentations differ, all infants aged 1–3 months suspected of having pneumonia (especially those whose mothers have a history of chlamydial infection) should be tested for C. trachomatis and treated if infected.

Specimens for chlamydial testing should be collected from the nasopharynx. Tissue culture is the definitive standard diagnostic test for chlamydial pneumonia. Nonculture tests (e.g., DFA and NAAT) can be used. DFA is the only nonculture FDA-cleared test for the detection of C. trachomatis from nasopharyngeal specimens, but DFA of nasopharyngeal specimens has a lower sensitivity and specificity than culture. NAATs are not FDA-cleared for the detection of chlamydia from nasopharyngeal specimens, and clinical laboratories must verify the procedure according to CLIA regulations (394). Tracheal aspirates and lung biopsy specimens, if collected, should be tested for C. trachomatis.


Because test results for chlamydia often are not available at the time that initial treatment decisions must be made, treatment for C. trachomatis pneumonia must frequently be based on clinical and radiologic findings, age of the infant (i.e., 1–3 months), and risk of chlamydia in the mother (i.e., age <25, multiple partners, and history of chlamydial infection). The results of tests for chlamydial infection assist in the management of an infant’s illness.

  • Erythromycin base or ethylsuccinate 50 mg/kg/day orally divided into 4 doses daily for 14 days
  • Azithromycin 20 mg/kg/day orally, 1 dose daily for 3 days

Because the effectiveness of erythromycin in treating pneumonia caused by C. trachomatis is approximately 80%, a second course of therapy might be required (532). Data on the effectiveness of azithromycin in treating chlamydial pneumonia are limited. Follow-up of infants is recommended to determine whether the pneumonia has resolved, although some infants with chlamydial pneumonia continue to have abnormal pulmonary function tests later in childhood.

Mothers of infants who have chlamydia pneumonia and the sex partners of these women should be evaluated, tested, and presumptively treated for chlamydia. For more information, see Chlamydial Infection in Adolescents and Adults.

Neonates Born to Mothers Who Have Chlamydial Infection

Neonates born to mothers who have untreated chlamydia are at high risk for infection; however, prophylactic antibiotic treatment is not indicated, as the efficacy of such treatment is unknown. Infants should be monitored to ensure appropriate treatment if symptoms develop.

Top of Page

Chlamydial Infections Among Infants and Children

Sexual abuse must be considered a cause of chlamydial infection in infants and children. However, perinatally transmitted C. trachomatis infection of the nasopharynx, urogenital tract, and rectum might persist for 2–3 years (see Sexual Assault or Abuse of Children).

Diagnostic Considerations

NAAT can be used for vaginal and urine specimens from girls (see Sexual Assault or Abuse of Children), although data are insufficient to recommend the use of NAAT in boys. Data also are lacking regarding use of NAAT for specimens from extragenital sites (rectum and pharynx) in boys and girls (394); other nonculture tests (e.g., DFA) are not recommended because of specificity concerns. Culture is still the preferred method for detection of urogenital C. trachomatis in boys and at extragenital sites in boys and girls.

Recommended Regimen for Infants and Children Who Weigh <45 kg
  • Erythromycin base or ethylsuccinate 50 mg/kg/day orally divided into 4 doses daily for 14 days

Data are limited on the effectiveness and optimal dose of azithromycin for the treatment of chlamydial infection in infants and children who weigh <45 kg

Recommended Regimen for Children Who Weigh ≥45 kg but Who Are Aged <8 Years
  • Azithromycin 1 g orally in a single dose
Recommended Regimens for Children Aged ≥8 years
  • Azithromycin 1 g orally in a single dose
  • Doxycycline 100 mg orally twice a day for 7 days

Other Management Considerations

See Sexual Assault or Abuse of Children.


A test-of-cure culture (repeat testing after completion of therapy) to detect therapeutic failure ensures treatment effectiveness. Therefore, this culture with should be obtained at a follow-up visit approximately 2 weeks after treatment is completed.

Top of Page

Treatment efficacy of azithromycin 1 g single dose versus doxycycline 100 mg twice daily for 7 days for the treatment of rectal chlamydia among men who have sex with men – a double-blind randomised controlled trial protocol

Study design and setting

This is a double-blind (clinicians and patients) RCT. Given our primary outcome is treatment efficacy, our trial is double blind to minimize bias that could arise as a result of the different dosing regimens of the two drugs (7 days vs single dose). For example: i) it is possible that taking a 7-day course of daily doxycycline rather than a single dose of azithromycin may deter people from resuming sexual activity while taking treatment, thereby reducing their risk of a new infection, and; ii) participants could be less adherent to a 7-day regimen which could impact efficacy . The trial will be conducted within sexual health clinics in Victoria and New South Wales in Australia and in accordance with the Declaration of Helsinki. The trial was approved by the Alfred Hospital Ethics Committee (373/15).

(NOTE: hereafter, “azithromycin” refers to azithromycin 1 g single dose and “doxycycline” refers to doxycycline (100 mg, twice daily for 7 days).

Duration of study

The trial will be of four weeks duration for each participant.

Participant eligibility

Inclusion criteria

Men will be eligible for inclusion if they report male to male sexual contact in the past 12 months, are aged ≥16 years and test positive for rectal chlamydia using a nucleic acid amplification test (NAAT). They must have adequate English and comprehension skills to give informed consent.

HIV positive MSM will be eligible to participate as there is no evidence that treatment efficacy differs by HIV status. A recent RCT comparing azithromycin with doxycycline for the treatment of chlamydia urethritis found no difference in efficacy between HIV positive and negative men . International STI management guidelines do not differentiate by HIV status for chlamydia treatment .

Exclusion criteria

Men will be excluded if they: i) report use of antibiotics for other purposes in the last 2 weeks; ii) have a known contraindication to the use of azithromycin or doxycycline including allergy; iii) present with symptomatic proctitis. Because MSM will be recruited at clinical services, it will not be possible to genotype their infections to detect LGV at recruitment. LGV genotyping will take place at the conclusion of the trial. Men who are randomised and subsequently found to have asymptomatic LGV based on genotyping at the conclusion of the trial, estimated to be <6% of the trial population will be excluded from our analysis as LGV requires more prolonged doxycycline treatment for cure . The sample size will account for this – see Sample Size.


MSM who are diagnosed with asymptomatic rectal chlamydia at participating clinics will be approached by a research nurse and invited to take part in the trial (Fig. 1). The nurse will explain the trial, assess eligibility and obtain consent. Eligible men will be enrolled and randomly assigned to either azithromycin or doxycycline. Participants will provide three self-collected rectal swab samples and complete a brief questionnaire. Self-collected swabs have been shown to have similar test performance compared with clinician-collected swabs for chlamydia testing . Once randomly allocated to a treatment group, the nurse will then directly observe participants taking the first dose of treatment (with food).

Fig. 1

Outline of trial schema. Follow up at 4 weeks post recruitment


Participants will be randomly allocated to one of the following treatment groups:

Azithromycin: Participants will receive 1 g of active azithromycin (500 mg tablets × 2), plus 13 placebo doxycycline tablets, identical in appearance to the active azithromycin. Participants will be required to take the two azithromycin tablets under observation at time of recruitment and then advised to take a single placebo tablet morning and night for the next 7 days;

Doxycycline: Participants will receive 14 active doxycycline tablets (100 mg), plus one placebo azithromycin tablet, all identical in appearance to active azithromycin. Participants will be required to take one active doxycycline and one placebo azithromycin tablets under observation at time of recruitment and then advised to take a single active doxycycline tablet morning and night for the next 7 days.

Participants will be advised to take the drugs with food to minimize gastrointestinal side effects and to minimize sun exposure or use sun screen to reduce the risk of photosensitivity.

Randomization and sequence generation, allocation concealment and blinding

A computer-generated randomization sequence will be created by an independent statistician. Blinded therapy will be prepared by an independent organization and labelled with individual kit numbers according to randomization. Study drugs will be packaged into individually numbered kits stored by independent site pharmacists. All tablets will be identical in appearance and feel, and all medications will be packaged identically to maintain blinding. Participants, physicians, nurses, trial statistician and all other trial staff will be masked to treatment group. The effectiveness of blinding will be tested at completion of the trial when participants will be asked to indicate which treatment they thought they received (including being able to indicate “don’t know”).

The side-effect profiles of the drugs will have negligible impact on blinding. They have been widely used for chlamydia for decades at the dosages we will be using. Their side-effect profiles are well established and similar including minor gastrointestinal upset (nausea, stomach cramps, diarrhoea, vomiting, gastric reflux) . Photosensitivity may occur for doxycycline but is more common with longer or higher dosages . Rash is a rare side effect for each drug, occurring in 0.1–1% of cases . Our packaging will clearly state sunscreen should be used and exposure to sun minimalized, thereby reducing the risk of photosensitivity. We examined the side-effect data from treatment trials for urethral/cervical chlamydia and found that among 17 trials, there was no difference in side-effects (24.0% for azithromycin vs 23.0% for doxycycline, p = 0.45) .


Primary outcome

Treatment efficacy measured as microbial cure defined as a negative chlamydia NAAT test result performed on a self-collected rectal swab at week 4.

Secondary outcomes

We will further differentiate between treatment failure and chlamydia re-infection using whole genome sequencing (WGS) and mRNA tests (see below for further detail) for any cases testing chlamydia NAAT positive on a rectal swab at week 4. Using the algorithm (Fig. 2), our secondary outcomes will be classified as: i) microbial cure based on a negative chlamydia NAAT test result at week 4; ii) false positive diagnosis if chlamydia NAAT positive at week 4, but no evidence of mRNA detected ; iii) new infection if infected with a different organism (based on sequencing results) OR if the same organism and the participant reports unprotected anal receptive sex between tests; iv) chlamydia treatment failure if infected with exactly the same organism and no reports of unprotected sex between recruitment and week 4 follow up. . We acknowledge that this classification will not be 100% accurate, but this level of discrimination has never been previously undertaken in any study of chlamydia treatment efficacy. Our RCT design should ensure that cases classified as a new infection or a false positive diagnosis will be evenly distributed between trial arms, minimising any differential measurement bias.

Fig. 2

Algorithm for defining repeat infection. PCR = polymerase chain reaction, WGS = whole genome sequencing, mRNA = messenger ribonucleic acid

Follow up

Men will be required to provide specimens and behavioral data until the conclusion of the trial at 4 weeks (Table 1). Men will be asked to attend the clinic at 4 weeks for a final study visit. At the 4-week visit, the research nurse will administer a final paper questionnaire and additional rectal swabs will be self-collected for WGS and mRNA assay.

Table 1 Trial timeline

Specimen collection

MSM will be asked to provide self-collected rectal swabs.

Specimen processing and extraction

All swabs will be sent to the Molecular Microbiology Laboratory, Royal Women’s Hospital for processing and testing. Swabs collected for routine NAAT and WGS will be rotated in 400 μL phosphate buffered saline for 30 s. Swabs collected for mRNA will be rotated in 1 ml of RNAlater (Lifetechnologies) preservative solution (Ambion, Austin, TX, USA) and stored at -80 °C until further testing is required. An aliquot of 200 μl will be extracted by the automated MagNA Pure 96 isolation and purification system (Roche Diagnostics, Mannheim, Germany) using the DNA and Viral NA Small Volume isolation kit. Following nucleic acid isolation, all samples will be initially assessed for DNA and RNA adequacy with a quantitative PCR for a 260 bp fragment of the human beta-globin gene and 226 bp fragment of U1A transcript. Chlamydia testing will be done by the Cobas 4800 CT/NG assay (Roche Applied Science) as per the manufacturer’s instructions.

Genotype (strain) determination

Identification of each chlamydia strain including LGV will be determined by qPCR assays using serovar-specific probes as we have described previously .

Whole genome sequencing (WGS)

Samples from MSM who test chlamydia NAAT positive at week 4 with the same genotype as their baseline sample will undergo WGS to identify the specific strain for each specimen and identify whether the organisms are identical. We will use a direct DNA probe capture method to capture chlamydial DNA directly from the swab sample and sequence the entire genome . Others have used OmpA genotyping or multi-locus sequence typing to characterise genovar , but these techniques are considerably less discriminatory than WGS. Our trial will be the first to use WGS to help differentiate between new infection and treatment failure.


To ensure only actively transcribed nucleic acid is evaluated (as a marker of active, viable infection), extracted nucleic acid will be treated with 10U/μl DNase (Roche Diagnostic) for 10 min at 37 °C, followed by inactivation of DNase. Resultant RNA will undergo one-step reverse transcription and qPCR using the method by Storm et al. . Any case that has mRNA detected will be classified as a true positive. Cases in which mRNA is not detected will be classified as false positive cases. Our trial will be the first to use mRNA assays to identify false positive cases.

Data collection (Table 1)

Questionnaire at recruitment

Participants will complete a paper-based survey at recruitment covering demographics and sexual health, including symptoms and sexual behaviour data. This will include: number of partners; types of sexual activity (including insertive/receptive anal sex); use of intra-rectal devices (eg sex toys); condom use; type of lubrication used and details about douching pre/post sex and types of fluids used for douching. The questions on douching, water based lubricants and intra-rectal devices have been included because they may reduce the antibiotic concentrations in the rectal mucosa due to epithelial damage . HIV status, use of pre-exposure prophylaxis for HIV or anti-retroviral therapy, and most recent viral load will be obtained from their medical record.

Weekly data collection

Participants will be asked to respond to a weekly short message service (SMS) that collects (via online link) whether they had: any receptive anal sex in the last week; sex with any new sexual partners; sex without a condom in the last week; used any douching and/or intra-rectal devices; any anogenital symptoms; any chlamydia testing elsewhere; taken any further antibiotics.

Side effect reporting

During the first week, participants will also be asked daily via SMS whether they had any diarrhoea or vomiting that could impact on their levels of antibiotic absorption.

At the 4-week follow up

Participants will complete another paper-based questionnaire that collects information regarding symptoms and sexual behaviour data, diagnosis of any STIs during follow up (which will be validated against their medical record) and what treatment they believe they received. We will also collect information about any recent HIV viral loads and/or CD4 counts.

Drug adherence monitoring

Participants will be asked to complete a questionnaire about drug adherence at the end of week 1. They will also be asked to return the pill bottle for a pill count as proxy measure of drug adherence. A previous study comparing self-report with measured adherence using the Medication Event Monitoring System, found 83% concordance between self-report and measured adherence for taking 11–14 doses among 206 men and women .

Adverse events reporting

We do not expect any severe adverse events as these drugs have been widely used for decades and their side-effect profiles are well-established. Nevertheless, we will record adverse events which will be coded using the Medical Dictionary for Regulatory Activities (MedDRA). The percentage of patients with treatment-emergent adverse events will be tabulated by system organ class and severity of these events with particular focus on gastrointestinal events together with severity of these events .

Sample size

Our hypothesis is that azithromycin efficacy will be less than that of doxycycline. On the basis of our meta-analysis, we assume that the microbial cure among the doxycycline arm at 4 weeks will be 98% compared to azithromycin at 93%. We will recruit 700 men in total (350 in each group) which, allowing for a very conservative 14% loss to follow up (based on our experience with similar trials of MSM) and a further loss of 6% due to a LGV diagnosis at the end of the trial, will give us an effective sample size of 560. This sample size will allow us to detect a 5% difference between doxycycline and azithromycin microbial cure at 4 weeks with 80% power and a 6% difference with 90% power. If microbial cure is 96% among those treated with doxycycline at week 4, then we will have 80% power to detect a 6% difference and 90% power to detect a 7% difference (Table 2).

Table 2 Sample size calculation


We will compare the proportion with microbial cure at 4 weeks between arms using the Chi square test, and 95% confidence intervals for the difference between proportions reported. While randomisation should ensure balance of baseline characteristics, if there are meaningful differences in baseline characteristics including sexual behaviour, a multivariable logistic regression analysis will be undertaken to adjust for these factors.

Primary analysis

Our primary analysis will be a modified intention to treat analysis (m-ITT) including only those who commenced randomised therapy at recruitment (at least one dose) and those who provided a rectal specimen for chlamydia testing at week 4.

Secondary analysis

We will undertake two per protocol analyses in which participants who took less than 10 doses of their allocated treatment or vomited within 1 h of any dose will be excluded: i) an analysis of the primary outcome of the microbial cure, and; ii) an analysis of the secondary outcome of microbial cure in which cases classified as new infection or a false diagnosis are grouped with microbial cure to create a binary variable for the analysis (microbial cure vs treatment failure).

Trial status

The trial has been registered on the Australian and New Zealand Clinical Trials Registry (ACTRN12614001125617). The trial commenced recruitment in August 2016 and is due to be completed by August 2019.

In This Section

  • Chlamydia
  • What are chlamydia symptoms?
  • Should I get tested for chlamydia?
  • How do I get treated for chlamydia?
  • How is chlamydia prevented?

Chlamydia can be easily cured with antibiotics. Your sexual partners need to be treated too. If you don’t treat chlamydia, it can lead to serious problems.

X in a circle

Want to get tested for chlamydia?

Find a Health Center A right arrow in a circle

What’s the treatment for chlamydia?

Chlamydia is usually easy to get rid of. Your nurse or doctor will get you antibiotics to treat the infection. Sometimes you only have to take one dose of medication. Another chlamydia treatment lasts for 7 days. Your doctor will help you figure out which treatment is best for you.

If you’re treated for chlamydia, it’s really important for your sexual partners to get treated also. Otherwise, you can keep passing the infection back and forth, or to other people. Sometimes your doctor will give you medicine for both you and your partner.

What do I need to know if I get treated for chlamydia?

If you’re getting treated for chlamydia:

  • Take all of your medicine the way your doctor tells you to, even if the symptoms go away sooner. The infection stays in your body until you finish the antibiotics.

  • Your partner(s) should also get treated for chlamydia so you don’t re-infect each other or anyone else.

  • Don’t have sex for 7 days. If you only have 1 dose of medication, wait for 7 days after you take it before having sex. If you’re taking medicine for 7 days, don’t have sex until you’ve finished all of your pills.

  • Get tested again in 3-4 months to make sure your infection is gone.

  • Don’t share your medicine with anyone. Your doctor may give you a separate dose of antibiotics for your partner. Make sure you both take all of the medicine you get.

  • Even if you finish your treatment and the chlamydia is totally gone, it’s possible to get a new chlamydia infection again if you’re exposed in the future. Chlamydia isn’t a one-time-only deal. So use condoms and get tested regularly.

What happens if you don’t get treated for chlamydia?

Even though chlamydia is common and doesn’t always cause any symptoms, it can become a big deal if it’s not caught and treated early.

Chlamydia can spread to your uterus and fallopian tubes, causing pelvic inflammatory disease (PID). PID might not have any symptoms at first, but there can be permanent damage that leads to pain, infertility, or ectopic pregnancy. Getting tested for chlamydia really reduces your chances of getting PID.

If you have a penis, a chlamydia infection can spread to your epididymis (a tube that carries sperm from your testicles), and can cause chronic joint pain. Rarely, it can make you infertile.

Having chlamydia may increase your chances of getting or spreading HIV, the virus that causes AIDS.

If you have chlamydia during your pregnancy and don’t treat it, you can pass it to your baby when you’re giving birth. Chlamydia can cause eye infections and pneumonia in newborns, and it also increases the risk of delivering your baby too early. Testing and treatment for chlamydia is quick, easy, and the best way to avoid all these problems.

Was this page helpful?

  • Yes
  • No

Help us improve – how could this information be more helpful?

How did this information help you?

You’re the best! Thanks for your feedback. Thanks for your feedback.

About the author

Leave a Reply

Your email address will not be published. Required fields are marked *