Review about the known risks of an abnormal heart rhythm regarding the use of azithromycin and other macrolide antibiotics


HALMED is aware of the results of the study published in the New England Journal of Medicine, on May 17, 2012, that compared the risks of cardiovascular death in patients treated with various antibiotics, including azithromycin.

Azithromycin is a broad-spectrum antibiotic which means that it acts against a large number of bacteria causing most common infections. This medicine belongs to a macrolide class of antibiotics. Apart from azithromycin, erythromycin and clarithromycin belong also to the same class of antibiotics. Macrolides are highly effective in treating bacterial infections, as they kill bacterial cells and not only prevent their further growth and multiplication. In Croatia are authorised antibiotics containing aforementioned active substances in different pharmaceutical forms and dosages.

It has been previously known for macrolide antibiotics that they are associated with a serious abnormalities of the heart rhythm, which occure rarely, but may be fatal. To these abnormalities belog the following conditions: prolongation of the QT interval, ventricular tachycardia and Torsade de pointes. Prolongation of the QT interval is a condition with an abnormal electric activity of the heart which represents a risk that may lead to a heart arrhythmias. In the ventricular tachycardia the heart rate is rapid and in the Torsade de pointes irregular and both conditions prevent the heart to squirt out an adequate blood amount. Therefore, these conditions are urgent and life threatening that require an urgent medical intervention. With regard to the very low occurence of these abnormalities of the heart rate and the high efficiency of these medications, the benefit risk ratio remains positive. Therefore, patients taking azithromycin may not disrupt their treatment without consulting with their doctor.

The information on these abnormalities of the heart rhythm is listed in summaries of the procuct characteristics of all the macrolide antibiotics authorised in Croatia. Also, in all the patient information leaflets, "accelerated or irregular heart rate" is listed as a possible adverse reaction which is the main symptom that may indicate the aforementioned abnormalities of the heart rhythm. Aforementioned abnormalities of the heart are not associated only to macrolide antibiotics, but to certain other antibiotics (fluoroquinolones), certain anti-depressants as well as to various other medications. The same as for macrolide antibiotics, the absolute risk of these abnormalities of the heart rhythm is extremly low and it does not affect the benefit risk ratio of the use of these medicines.

Due to the aforementioned, the results of the study published in New England Journal of Medicines are expected, given that azithromycin, as the only medicine from the macrolide antibiotic class was compared to antibiotics of other classes.

HALMED has never received any adverse reaction report of an abnormal heart rhythm with a fatal outcome to any medicine of the macrolide antibiocs class.

HALMED has never received any adverse reaction report of prolongation of the QT interval, ventricular tachycardia or Torsade de pointes to azithomycin.

HALMED received one adverse reaction report of ventricular tachycardia to clarithromycin in 2005. The patient has recovered after doctor's decision to stop the treatment with this medication.

HALMED will continue to monitor the safety of the use of azithromycin and other antibiotics and will make every new information publicly available in due time.

We remind healthcare professionals that they should report any adverse reaction to HALMED, as well as quality defect. Patients who have developed any adverse reaction to medicinal product may report it directly to HALMED via form or on-line application, with recommendation regarding any adverse reaction they discover to consult with their doctor or pharmacist about the continuation of their therapy.