Which treatment is indicated for a TCA overdose with SBP <90, QRS >0.12 seconds, and seizures?

Which treatment is indicated for a TCA overdose with SBP <90, QRS >0.12 seconds, and seizures?

• A. Sodium bicarbonate infusion
• B. Naloxone
• C. Activated charcoal
• D. Flumazenil

Answer: (A)

The main idea is that this is a TCA overdose causing dangerous cardiac conduction problems because TCAs block cardiac sodium channels. When the QRS is widened and the patient is hypotensive, what you’re treating is the sodium channel blockade. Sodium bicarbonate infusion is the best choice because it does two things at once: it provides a large sodium load to help overcome the channel blockade, and it alkalinizes the blood. The higher pH reduces the drug’s affinity for the sodium channels and shifts the drug away from the heart, which narrows the QRS and stabilizes conduction. This rise in sodium availability and alkalinization also helps improve blood pressure and reduce the risk of life‑threatening arrhythmias. Activated charcoal can be considered early if the airway is protected and the patient can be safely treated, but it doesn’t address the ongoing sodium-channel blockade once seizures or severe cardiotoxicity are present. Naloxone is aimed at opioid overdose and won’t correct the sodium-channel–driven toxicity. Flumazenil can precipitate seizures in TCA overdose and is not appropriate.

The main idea is that this is a TCA overdose causing dangerous cardiac conduction problems because TCAs block cardiac sodium channels. When the QRS is widened and the patient is hypotensive, what you’re treating is the sodium channel blockade. Sodium bicarbonate infusion is the best choice because it does two things at once: it provides a large sodium load to help overcome the channel blockade, and it alkalinizes the blood. The higher pH reduces the drug’s affinity for the sodium channels and shifts the drug away from the heart, which narrows the QRS and stabilizes conduction. This rise in sodium availability and alkalinization also helps improve blood pressure and reduce the risk of life‑threatening arrhythmias.

Activated charcoal can be considered early if the airway is protected and the patient can be safely treated, but it doesn’t address the ongoing sodium-channel blockade once seizures or severe cardiotoxicity are present. Naloxone is aimed at opioid overdose and won’t correct the sodium-channel–driven toxicity. Flumazenil can precipitate seizures in TCA overdose and is not appropriate.