Which antidote is utilized for treating toxicity caused by tricyclic antidepressants?

Sodium bicarbonate is the antidote of choice for treating toxicity caused by tricyclic antidepressants (TCAs) due to its ability to counteract metabolic acidosis and its effect on cardiac toxicity associated with TCA overdose. In cases of TCA overdose, patients often present with cardiovascular complications such as arrhythmias or effects on heart conduction because these medications can cause sodium channel blockade. By administering sodium bicarbonate, the serum pH is increased, which helps to stabilize the myocardial membrane and improve the conduction of electrical impulses through the heart. Moreover, the alkalinizing effects can help facilitate the excretion of the drug from the body, reducing the overall levels of the toxic substance.

Other options, while they have specific uses in treating different toxicities, do not address the specific complications associated with TCA overdose. Pyridoxine is primarily used for treating toxicity from isoniazid and glycine, while dimercaprol is used for heavy metal poisoning, and Crotalidae polyvalent antivenin is utilized in cases of snake bites. Therefore, sodium bicarbonate uniquely addresses the life-threatening issues posed by tricyclic antidepressant toxicity.