Twenty-four pediatric studies, published from various centers between 1967 and 1996, involving 730 children and adolescents treated with imipramine, amitryptiline, desipramine, or nortryptiline, were surveyed for cardiovascular side effects at the Massachusetts General Hospital, Boston, MA. Treatment with tricyclic antidepressants (TCA) caused small increases in blood pressure and heart rate, and lengthening of PR, QRS, and QT conduction parameters on the ECG. Imipramine may be associated with lower rates of sinus tachycardia and intraventricular conduction lengthening than other TCAs, and desipramine may have the greatest tendency to cause QT prolongation. ECG abnormalities were related to the dose and relatively higher serum TCA levels. ECG monitoring is recommended with doses of TCAs of 2.5 mg/kg day (1 mg/kg day for nortryptyline), and doses more than 5 mg/kg day should be avoided. Lightheadedness or headaches signal the need for a check of vital signs, ECG, and TCA serum levels. Guidelines for monitoring ECG and vital signs in children receiving TCAs are suggested. 
COMMENT. Tricyclic antidepressants are a second-line choice of medication for ADHD, sometimes favored in children with psychiatric comorbidity or enuresis. Although in general the cardiovascular effects are minor, tachycardia and shortness of breath, and occasional reports of idiosyncratic fatalities in TCA-treated children are a concern to some practitioners. Without frequent ECG monitoring, it is likely that these cardiovascular abnormalities and associated symptoms are often unrecognized. Children engaged in sporting activities especially should be closely examined for cardiac related side effects, and alternative treatments substituted.
Protriptyline for ADHD. Side effects were particularly prominent in a trial of protriptyline in 13 children with ADHD, and less than 50% showed a positive response.