Which treatment is the choice for QRS prolongation in TCA overdose?

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Multiple Choice

Which treatment is the choice for QRS prolongation in TCA overdose?

Explanation:
QRS prolongation from TCA overdose happens because these drugs block fast sodium channels in the heart, slowing depolarization and conduction. The treatment choice targets reversing that sodium-channel blockade. Intravenous sodium bicarbonate raises the extracellular sodium concentration, which helps overcome the channel blockade and stabilize conduction. At the same time, increasing serum pH (alkalinization) reduces the drug’s affinity for the sodium channel, further narrowing the QRS and lowering the risk of serious arrhythmias. Clinically, you give a sodium bicarbonate bolus (about 1–2 mEq/kg) and then a continuous infusion to maintain a pH roughly in the 7.45–7.55 range, while closely monitoring the ECG and acid-base status. Activated charcoal is for reducing absorption if given early, calcium gluconate isn’t effective for reversing TCA-induced sodium-channel blockade, and naloxone is for opioid toxicity, not this scenario.

QRS prolongation from TCA overdose happens because these drugs block fast sodium channels in the heart, slowing depolarization and conduction. The treatment choice targets reversing that sodium-channel blockade. Intravenous sodium bicarbonate raises the extracellular sodium concentration, which helps overcome the channel blockade and stabilize conduction. At the same time, increasing serum pH (alkalinization) reduces the drug’s affinity for the sodium channel, further narrowing the QRS and lowering the risk of serious arrhythmias. Clinically, you give a sodium bicarbonate bolus (about 1–2 mEq/kg) and then a continuous infusion to maintain a pH roughly in the 7.45–7.55 range, while closely monitoring the ECG and acid-base status. Activated charcoal is for reducing absorption if given early, calcium gluconate isn’t effective for reversing TCA-induced sodium-channel blockade, and naloxone is for opioid toxicity, not this scenario.

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