The day after admission the patient was extubated and alert and oriented. Her EKG was normal. She was transferred to psychiatry on the fourth hospital day. Tricyclic antidepressants are commonly prescribed agents that are often lethal in overdose. The cardiac toxicity of these agents is due to sodium channel blockade.
Sodium bicarbonate is effective in reversing some of the cardiotoxicity.
The goal of sodium bicarbonate therapy is serum, not urine alkalinization since elimination is mostly by hepatic metabolism. Renal excretion of the tricylic antidepressants is minimal. Amitriptyline is metabolized to nortriptyline by the liver, so both agents are reported on a serum tricyclic screen. In the unknown overdose patient the electrocardiogram is a valuable tool. Initial evaluation in the ED revealed an alert, uncooperative patient who was demanding to go home.