Tricyclic antidepressant poisoning

Tricyclic antidepressant poisoning causes predictable electrocardiographic abnormalities and can be lethal. Cardiac arrhythmias, hypotension, seizures, and coma are common. Sodium bicarbonate is still considered the treatment of choice for severe toxicity, although a variety of supportive measures may be taken. Hypertonic saline appears to be a promising alternative. A QRS interval longer than 100 ms appears to be a better predictor of serious complications than is an elevated serum tricyclic antidepressant level. Cardiovascular toxicity is classically manifested as ventricular dysrhythmias, hypotension, heart block, bradyarrhythmias, or asystole. Activated charcoal binds tricyclic antidepressants. Give 30 to 50 g orally or by nasogastric tube with or without a cathartic (sorbitol 0.5 g/kg or 30 g of magnesium sulfate). Sodium bicarbonate is indicated if the QRS duration is more than 100 ms or the terminal right-axis deviation is more than 120 degrees. The suggested dosage is 1 to 2 mEq/kg, repeated as needed. Tricyclic antidepressants are used not only for depression but also for chronic pain syndromes, obsessive-compulsive disorder, panic and phobic disorders, eating disorders, migraine prophylaxis, and peripheral neuropathies.