Mild to moderate poisoning usually occurs when more than 10 mg/kg of tricyclic is ingested. Such patients may present with dilated pupils, dry mouth, drowsiness, sinus tachycardia, urinary retention, increased tendon reflexes, and extensor plantar responses.
Severe poisoning usually occurs when more than 15 - 20 mg/kg is ingested. These patients often present with fits, coma, and cardiac arrhythmias. Death from cardiac arrest may also occur.
Symptoms usually appear within 30 to 60 minutes of ingestion, and reach their peak intensity within 4 to 12 hours.
Death is rare when less than 1 g is ingested.
About 7% of all suicides are antidepressant related.