Chlamydia, Antibiotic Prescribing

Doses are oral and for adults unless otherwise stated. Visit the Health Products Regulatory Board 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.

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. Infection can lead to epididymo-orchitis 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.
  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.
  9. Hepatitis C testing should be considered part of routine sexual health screening in the following circumstances: People who are HIV positive; Commercial sex workers; PWID Patients who inject drugs ; If indicated by the clinical history e.g. unexplained jaundice; When other risk factors for HCV are present, for example MSM. The full set of recommendations around HCV testing are available in the national HCV screening guidelines.
  10. 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
  11. Chlamydia is a notifiable disease. The complete list of notifiable diseases and information on the notification process is available from HPSC.


Treatment of uncomplicated anogenital Chlamydia is outlined in the table below.

chlamydia treatment table 2019

1 Avoid use of doxycycline in pregnancy and breastfeeding. Use earlier than 11 weeks gestation is unlikely to cause harm. Use beyond 11 weeks gestation is contraindicated

Useful resources

Patient Information

Reviewed October 2018

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