Doctors treat chlamydia infections with antibiotics. Typically, these are given as a one-off dose, but in some cases a longer course may be necessary.

At present, the first line options for uncomplicated genital chlamydia in the UK are Doxycycline and Azithromycin.

According to NICE guidelines, Doxycycline is given as a twice daily, one week course, and is the preferred candidate in cases where signs of rectal infection are present; whereas Azithromycin is used in other cases and is given over three days.

However, a doctor may recommend a different medication if a patient’s medical profile means that the first line options are unsuitable.

On this page, you’ll find information on:

  1. Why treating chlamydia is important

  2. What antibiotics are used to treat it

  3. What alternatives are sometimes used in certain cases

  4. Whether treatment can be started prior to test confirmation

  5. Where you can get treatment from

  6. How antibiotics for chlamydia are administered

  7. How antibiotics for chlamydia work

  8. What extra measures need to be taken during treatment

Why is treating chlamydia important?

Untreated chlamydia can lead to several serious complications, including pelvic inflammatory disease, or epididymitis. In some cases these conditions can cause infertility.

Those who do not seek treatment for chlamydia also risk passing the infection on to their sexual partners.

Treatment is also necessary because the immune system is not capable of fighting off the infection on its own. The only way to effectively rid the body of chlamydia is to treat it with antibiotics.

What antibiotics are used to treat chlamydia?

Currently, NICE recommends Azithromycin or Doxycycline as the first-line drugs for uncomplicated genital chlamydia infections. According to their guidelines, Doxycycline is preferred in instances where the patient shows signs of a rectal infection. Azithromycin is used in other cases.

  • Doxycycline is given as a 100mg tablet, taken twice daily for one week.
  • Azithromycin is issued for use over three days. A 1g dose on the first day, followed by two 500mg doses.

What are second-line treatments?

If a particular medication is not suitable for a person due to their medical profile, then an alternative may be issued in some cases.

This order of preference is sometimes referred to as first-line, second-line, third-line and so on.

In the case of chlamydia, other antibiotics may be prescribed to treat the condition in instances where Doxycycline and Azithromycin are not suitable for the patient.

This may be due to a pre-existing condition, or a medical intolerance to something in the drugs.

In such cases, NICE guidelines recommend:

  • a course of Erythromycin, given in 500mg doses twice daily for 10 days to two weeks; 
  • or Ofloxacin, given in 200mg doses twice daily for one week.

How is chlamydia treated during pregnancy?

Because Doxycycline and Ofloxacin are not suitable for use in pregnancy, expectant mothers requiring chlamydia treatment will be given an alternative.

NICE recommends that prescribers consider one of the following in such cases:

  • a three day course of Azithromycin (1g on the first day and 500mg on the following two days)
  • or a seven day course of Erythromycin (500mg, taken four times per day)
  • or a 14-day course of Erythromycin (500mg taken twice daily)
  • or a seven day course of Amoxicillin (500mg taken three times per day)

Of course every case is different, and dependent on a patient’s medical profile.

Should chlamydia treatment start before test results are confirmed?

In certain instances, a doctor may advise beginning treatment for chlamydia before the diagnosis is confirmed through test results. These will usually be instances where the patient displays signs which are strongly indicative of a chlamydia infection (such as one or more of the symptoms outlined in our information page).

NICE guidelines also state that partners of those with a confirmed chlamydia diagnosis should begin treatment ‘irrespective of their test result’.

Even in such cases, however, the patient(s) should still be screened for chlamydia (and other sexually transmitted infections) as soon as possible, to confirm the diagnosis.

Someone who has no symptoms, however, but thinks they may have come into contact with the infection, might be advised to wait for confirmation before commencing treatment.

Where you can get Chlamydia treatment from

Ideally, you should always get tested and treated for STIs in person.

The recommended place to get tested and treated for chlamydia and other STIs is at a genitourinary medicine (GUM) clinic. They provide specialist services in this particular area, and can also provide assistance to patients who need to notify their partners. Following testing, those requiring treatment for chlamydia will be advised to return to the clinic, where they will be issued a prescription for the medication they need by a healthcare professional. This can then be dispensed at any chemist.

A GP will strongly advise someone who thinks they may have an STI to go to a GUM clinic. However, in cases where a person is either unable or unwilling to go to a GUM clinic, a GP practice may be able to offer testing and treatment.

People who are unable to attend a consultation in person at their GUM clinic or GP can also access testing and treatment services online. Self-testing kits are available to buy from online pharmacies, and many of these platforms also offer remote consultations with practising doctors. These doctors can then prescribe treatment in cases where someone has a positive test result, or again if the patient is experiencing symptoms which strongly point towards chlamydia.

It is not possible to purchase self-testing kits or chlamydia treatment from our online service.

Those looking to buy treatment online however should always make sure the pharmacy they are using is genuine and registered with the relevant supervisory body.

How antibiotics for chlamydia are administered

Antibiotics for uncomplicated genital chlamydia infections are taken orally.

  • Where Azithromycin (also known as Zithromax or Clamelle) is used, it is given as a three day course. This will usually be two 500mg tablets on the first day, followed by one 500mg tablet on the second and third days.
  • If Doxycycline is used, NICE recommends 100mg taken twice a day for one week. So one dose might be one 100mg tablet, or two 50mg tablets.
  • Ofloxacin might be given as a once daily 400mg dose for one week, or a 200mg dose twice daily for one week.
  • Erythromycin for chlamydia might also be prescribed in one of two ways: as a 500mg dose (two 250mg tablets) taken four times daily for one week; or as a 500mg dose (two 250mg tablets) taken twice a day for up to two weeks.
  • Amoxicillin is given as a 500mg dose (two 250mg tablets or one 500mg tablet), taken three times daily for one week.

However, in any case, you should always follow the specific instructions issued to you by your doctor.

How antibiotics for chlamydia work

Chlamydia is caused by a bacteria called Chlamydia trachomatis.

In the body, an infection spreads when the bacterial cells causing it multiply. The way antibiotics work in stopping the spread, is to prevent the bacteria from producing certain proteins. The bacterial cells need these proteins to sustain themselves and grow; but by stopping the bacteria from generating them, the antibiotic agent helps to stop the bacteria from growing, and spreading the infection. The immune system is then able to fight off the infection and symptoms start to clear up.

What extra measures need to be taken during treatment

If someone suspects they or their partner has come into contact with chlamydia, or are displaying symptoms of chlamydia, they should get tested immediately, and refrain from having sexual intercourse until they have either:

  • received confirmation that they and their partner are clear of infection;

or, if they or their partner has tested positive for chlamydia:

  • waited for seven days following successful completion of treatment with antibiotics and the disappearance of any symptoms.

If symptoms persist, you should notify your doctor as soon as possible.

In certain cases, a person may be advised to undertake a test of cure following treatment, to confirm that the infection is no longer present, before having sex again. This test should be taken at least three weeks following completion of treatment.

Where a person has tested positive for chlamydia, or has not yet tested positive but is strongly suspected of having the infection, it is crucial for them to notify their sexual partner(s) as soon as possible. Sexual services such as GUM clinics can provide help in doing so.

Patients will also be given information on safe sex practices, to help reduce their risk of infection in future.

Page last reviewed:  09/12/2020