title: Torsades de pointes induced by the concomitant use of ivabradine and azithromycin: an unexpected dangerous interaction.
abstract: A 68-year-old man had a cardiac syncope. He was known to have a long QT-interval and was treated with ivabradine for paroxysmal sinusal tachycardia. In the last 5 days, azithromycin had been prescribed for sinusitis. An electrocardiogram showed torsades de pointes (TdP). Azithromycin is known to prolong the QT-interval. Ivabradine does not affect the QT-interval but has a conditional risk of TdP when taken with other drugs that block its metabolic breakdown. This case presents the specific problem of a patient with long QT who received two medications, which may interact and prolong the QT.
authors.affiliation: Cardiology Office, Postfach 119, Marktgasse 10A, 4310, Rheinfelden, Switzerland, praxis@cocco.ch.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cocco
authors.forename: Paul
authors.initials: P
authors.lastname: Jerie
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D017963:Azithromycin / Q000009:adverse effects*; D001552:Benzazepines / Q000009:adverse effects*; D002317:Cardiovascular Agents / Q000009:adverse effects*; D004347:Drug Interactions; D004562:Electrocardiography; D006801:Humans; D000077550:Ivabradine; D008297:Male; D016171:Torsades de Pointes / Q000139:chemically induced*
chemical_list: D000900:Anti-Bacterial Agents; D001552:Benzazepines; D002317:Cardiovascular Agents; D000077550:Ivabradine; D017963:Azithromycin