Cardiovascular changes and plasma drug levels after amitriptyline overdose.

Electrocardiographic and blood pressure parameters in 17 patients after amitriptyline overdose were reviewed in a retrospective study. Seven patients for whom baseline electrocardiograms (EKGs) were available showed significant increases in heart rate and QRS duration after overdose. Ventricular arrhythmias were observed in only one case, the sole fatality, who demonstrated the highest amitriptyline plus nortriptyline plasma level. Most patients experienced sinus tachycardia (88%) and hypotension (53%). Widened PR and QRS after overdose also were common. For the total group, postoverdose TCAD levels correlated with PR (r = .66, p less than .01) and QRS (r = .55, p less than .05) values, and with lowest observed systolic (r = -.60, p = .01) and diastolic blood pressure (r = .50, p less than .05) but not QTc or heart rate. The difference between the mean TCAD levels of subjects with lowest systolic blood pressure less than 100 mmHg and those with higher readings was significant at the 0.05 level.