A Canadian family doctor reports that an interaction between tricyclic
antidepressants and marijuana can produce a life-threatening arrhythmia.
His patient, a 17-year-old boy, had been prescribed 25 mg of amitriptyline
to help him sleep and alleviate some of his depression. A week after filling
the prescription the boy showed up in the emergency ward with a supraventricular
tachycardia rate of 300 beats per minute. He had been smoking marijuana
the evening and night before. The doctor speculates that the amitriptyline
and marijuana interacted to produce the arrhythmia and cautions against
prescribing tricyclic antidepressants to adolescents who have a potential
for drug abuse.