Macrolide warning

Treatment with macrolides including clarithromycin has resulted in prolonged cardiac repolarisation and QT interval, resulting in cardiac dysrhythmia and torsade de pointes. There are alternative treatment options available for most clinical conditions including penicillin allergy. 

In a recent European Medicines Agency review of cardiovascular risk with clarithromycin, a rare short term risk of dysrhythmia, myocardial infarction and cardiovascular mortality, associated with all macrolides, was identified in some observational studies.

Consideration of these findings should be balanced with treatment benefits when prescribing macrolides in patients with pre-existing heart disease.

 Macrolides must not be used in the following situations:

  • Patients with known QT prolongation or a history of ventricular dysrhythmia.

Macrolides are strongly advised against or should be avoided in the following situations:

Consider alternatives or seek advice

Patients on medications that prolong the QT-interval e.g. antipsychotic medication including atypical antipsychotics, amiodarone & other anti-arrhythmics, some antidepressants (tricyclic antidepressants and SSRIs and MAOIs), alfuzosin, domperidone, galantamine, indapamide, lithium, methadone, quinine sulphate, tamoxifen, tizanidine. This is not a complete list, for a composite list of drugs that can prolong QT Interval please consult the relevant SmPC on HPRA website, the BNF or for further information. NB: Consider OTC medication patient may be taking. 

Macrolides may be used with caution in the following situations:

  • In patients with heart disease and electrolyte disturbances i.e. hypomagnesemia, hypokalaemia. Consider use of alternative safer antibiotics if suitable to treat the clinical condition. These may include penicillins or in the case of penicillin allergy alternatives may be doxycycline or trimethoprim.  See penicillin allergy page

Check options on each clinical condition page.

SmPCs of the individual medicines (see sections 4.3, 4.4, 4.5 and 4.8) are available at