Korean Circ J.  1998 Mar;28(3):463-470. 10.4070/kcj.1998.28.3.463.

A Case of Torsade de Pointes after Combined Use of Terfenadine and Itraconazole

• Ahn HS
• Lim ST
• Lee SO
• Chai JK
• Kim WH
• Ko JK

• KMID: 1858146
• DOI: http://doi.org/10.4070/kcj.1998.28.3.463

Abstract

Torsade de pointes is a life-threatening, polymorphic ventricular tachycardia associated with prolongation of the QTc interval. Although torsade de pointes is found in many clinical settings, it is mostly drug induced. Similar problems have been described with nonsedating H1-selective antihistamines like terfenadine and astemizole. The increased risks of both H1-antihistamines were associated with exposure to supratherapeutic doses or concomitant exposure to the cytochrome P-450 inhibitors, ketoconazole, erythromycin and cimetidine. We report a 51-year-old woman with torsade de pointes and a long QTc interval caused by the combined use of terfenadine and itraconazole. After discontinuation of these drugs and treatments with electrical cardioversion and magnesium sulfate, torsade de pointes and prolonged QTc interval were no longer observed and she was discharged in good condition with a normal ECG. In conclusion, physicians should be aware that terfenadine and astemizole can cause torsade de pointes in rare cases.

Keyword

Terfenadine; Itraconazole; Prolonged QT interval; Torsade de pointes

MeSH Terms

Astemizole
Cimetidine
Cytochrome P-450 Enzyme System
Electric Countershock
Electrocardiography
Erythromycin
Female
Histamine Antagonists
Humans
Itraconazole*
Ketoconazole
Magnesium Sulfate
Middle Aged
Tachycardia, Ventricular
Terfenadine*
Torsades de Pointes*
Astemizole
Cimetidine
Cytochrome P-450 Enzyme System
Erythromycin
Histamine Antagonists
Itraconazole
Ketoconazole
Magnesium Sulfate
Terfenadine