Torsades de pointes following clarithromycin treatment

Abstract

A 75-year-old woman presenting with pre-syncope, shortness of breath and nausea was admitted to the emergency department following treatment with clarithromycin. Shortly after admission she developed a prolonged QT interval leading to torsades de pointes (TdP) and cardiac arrest. She was successfully cardioverted and clarithromycin was discontinued resulting in restoration of her usual QT interval. This case is an example of acquired long QT syndrome; a disorder that can be precipitated by macrolide antibiotics such as clarithromycin. Additional risk factors present in this case include: female gender, old age, heart disease, hypokalemia and hypomagnesemia. In this manuscript we comprehensively review past cases of clarithromycin-induced long QT syndrome (LQTS) and discuss them within the context of this case.

Keywords::

• acquired long QT syndrome
• clarithromycin
• torsades de pointes

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• • Clarithromycin, a commonly prescribed macrolide antibiotic, can cause QT interval prolongation, torsades de pointes and cardiac arrest in the setting of multiple comorbidities.

• • Acquired long QT syndrome often occurs in the setting of multiple risk factors including: electrolyte imbalance, heart disease, bradycardia, old age, female gender and genetic predisposition.

• • Caution should be exercised when prescribing clarithromycin for patients with reduced repolarization reserve.

• • The high frequency with which macrolide antibiotics are prescribed calls for continued characterization of the risks of QT interval prolongation and torsades de pointes with clarithromycin therapy.