title: Ketoconazole induced torsades de pointes without concomitant use of QT interval-prolonging drug.
abstract: Ketoconazole is not known to be proarrhythmic without concomitant use of QT interval-prolonging drugs. We report a woman with coronary artery disease who developed a markedly prolonged QT interval and torsades de pointes (TdP) after taking ketoconazole for treatment of fungal infection. Her QT interval returned to normal upon withdrawal of ketoconazole. Genetic study did not find any mutation in her genes that encode cardiac IKr channel proteins. We postulate that by virtue of its direct blocking action on IKr, ketoconazole alone may prolong QT interval and induce TdP. This calls for attention when ketoconazole is administered to patients with risk factors for acquired long QT syndrome.
authors.affiliation: Cardiology Team, Department of Medicine & Geriatrics, Princess Margaret Hospital, Hong Kong, China. isaacmok@netvigator.com
authors.forename: Ngai-Shing
authors.initials: NS
authors.lastname: Mok
authors.forename: Ying-Keung
authors.initials: YK
authors.lastname: Lo
authors.forename: Ping-Tim
authors.initials: PT
authors.lastname: Tsui
authors.forename: Ching-Wan
authors.initials: CW
authors.lastname: Lam
mesh_terms: D000935:Antifungal Agents / Q000009:adverse effects*; D003324:Coronary Artery Disease / Q000235:genetics / Q000503:physiopathology; D005260:Female; D006801:Humans; D007654:Ketoconazole / Q000009:adverse effects*; D008133:Long QT Syndrome / Q000139:chemically induced*; D008875:Middle Aged; D009154:Mutation; D012307:Risk Factors; D016171:Torsades de Pointes / Q000139:chemically induced* / Q000235:genetics
chemical_list: D000935:Antifungal Agents; D007654:Ketoconazole