Response to glucagon in imipramine overdose.

A 25-year-old woman, severely hypotensive following a massive imipramine overdose, had an immediate and sustained rise in blood pressure following intravenous glucagon (10 mg bolus followed by an infusion of 10 mg over 6 h). The QRS interval on the electrocardiogram shortened from 129 to 89 msec. Glucagon should be considered in hypotension following tricyclic antidepressant overdose; it may also be antiarrhythmic.