Doses are oral and for adults unless otherwise stated. Visit the Health Products Regulatory Board website or the printed Irish Medicines Formulary for drug SPCs, dosage, contraindications, interactions, or IMF/BNF/BNFC/MIMS. See guidance on dosing in children for quick reference dosage/weight guide.

Letters indicate strength of evidence range from A+ (systematic review) to D (informal opinion). Statins can interact with some antibiotics and increase the risk of rhabdomyolysis. Amiodarone and drugs which prolong the QT interval can interact with many antibiotics. Many antibiotics increase the risk of bleeding with anticoagulants. Please refer to our Drug Interactions Table for further information.

Comments from Expert Advisory Committee

  1. Chlamydia, caused by Chlamydia trachomatis, is the commonest STI reported in Ireland with almost half of cases diagnosed in those aged between 15 and 24 years
  2. Frequently asymptomatic in both males and females. Symptoms in males include dysuria and a urethral discharge. Symptoms in women include vaginal discharge, intermenstrual bleeding, post coital bleeding
  3. Can lead to epidydmorchitis in males.
  4. Can lead to pelvic inflammatory disease in females. PID is associated with an increased risk of tubal factor infertility, ectopic pregnancy and chronic pelvic pain
  5. Diagnosis using NAAT (nucleic acid amplification technique, eg PCR, polymerase chain reaction) is the current diagnostic gold standard. This is frequently combined with a gonorrhoea NAAT in the same test
  6. Diagnosis can be made on first void urine in males and vulvovaginal or endocervical swab in females. Vulvovaginal swabs can be provider or self-taken, further information on this is available in the ICGP STI e-learning module
  7. In sexually active men who have sex with men (MSM), depending on sexual exposure, pharyngeal and rectal sites should be tested too. Test of cure is not routinely required but is suggested in pregnancy and in women with an intrauterine device. If doing a test of cure, wait until at least 3 weeks post completion of treatment
  8. Individuals diagnosed with chlamydia should be offered testing for other STIs including HIV, Hepatitis B, syphilis and gonorrhoea. Hepatitis C testing should be offered to those with a history of injecting drug use and MSM, further information on this is available in the ICGP STI e-learning module
  9. Sexual partners in the preceding 6 months should be informed of the need for testing and patients should be encouraged to inform their sexual partners
  10. Chlamydia is a notifiable disease. The complete list of notifiable diseases and information on the notification process is available from HPSC.


See guidance on dosing in children for quick reference dosage/weight guide.

Treatment Dose TX Duration Comment
azithromycinA+ 1 g stat 1 hr before or 2 hrs after food
OR doxycyclineA+ 100 mg BD 7 days

contraindicated in pregnancy

first line in rectal infection

OR erythromycinA 500 mg QDS 7 days less effective than other options

Useful resources

Patient Information

We recommend patients use the website developed by HSE/ICGP/IPU partnership for tips on how to get better from common infections without using antibiotics, what you can do for yourself or a loved one and when to seek help.

The HSE Health A-Z website provides patient information on many hundreds of conditions and treatments.

Reviewed June 2017

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