EKG Effects of Imipramine Treatment in Children

There are increasing reports of serious side effects in children with clinical use of imipramine in high doses. Our analysis of the EKG effects of imipramine in 25 hyperactive and 8 school phobic children suggests that children on a dose of imipramine of 3.5 mg/kg or more are likely to show an increase in PR interval of .02 seconds or more and that such increases are more likely to occur in patients with a small pretreatment PR interval. In 7 children the PR interval prolongation was above the rate-corrected norm. EKG monitoring seems desirable in children maintained on imipramine dose of 3.5 mg/kg or more. Imipramine cardiotoxicity was originally described by Sigg et al. (1963) in dogs. Cardiotoxicity studies in dogs of (IMI) and its me- tabolites (DMI), (2-OH IMI), and (2-OH DMI) show that all four compounds affect cardiac function (Buckley et al., 1973). They significantly decrease cardiac output, left ventricular work, heart rate, and cardiac contractibility while blood pressure is main- tained due to compensatory increase in peripheral vascular resis- tance. 2-OH IMI at a dose of .?mg/kg I.V. is exceedingly cardio- toxic and may produce death by cardiac arrest. Tricyclic antidepressant therapy in adults has been associated