We investigated the effect of carbamazepine (CBZ) cotreatment with haloperidol (HP) on cardiac change in Japanese psychiatric patients without heart disease. Of 21 patients cotreated with CBZ, 11 showed lengthening of QT interval corrected for heart rate (QTc) (>440, mean percentage change, 29), of whom two patients developed congestive heart failure because of left ventricular dysfunction. Especially in these two patients, plasma HP levels were significantly higher than speculated from the correlations. It is possible to speculate that, especially on CBZ cotreatment, significantly higher HP plasma level with QTc prolongation may herald heart failure.
Address correspondence and reprint requests to Dr. K. Iwahashi at Department of Neuropsychiatry, Kagawa Medical School, Kida-gun, Miki-cho, Kagawa 761-01, Japan.
© Williams & Wilkins 1996. All Rights Reserved.