Drug given for OD on amitriptyline (tricyclic antidepressant)

• A. Sodium Bicarbonate
• B. Naloxone
• C. Flumazenil
• D. Activated Charcoal

Answer: (A)

In amitriptyline (a tricyclic antidepressant) overdose, the life-threatening problem is the drug’s effect on cardiac sodium channels, which slows conduction and can cause dangerous heart rhythms. Intravenous sodium bicarbonate is used because it tackles this toxicity in two ways: it provides a large sodium load to help overcome the sodium-channel blockade, and it alkalinizes the blood to reduce the drug’s binding to cardiac receptors and stabilize myocardial conduction. Clinically, this is reflected in narrowing of the QRS complex and improved hemodynamics. While activated charcoal can limit absorption if given early, and naloxone or flumazenil target other drug overdoses (opioids and benzodiazepines, respectively), they do not reverse the cardiac toxicity seen with TCAs.