What are two common risks/side effects of TCAs and why are they clinically monitored?

• A. Sedation and respiratory depression
• B. Weight gain and liver toxicity
• C. Hypertension and hyperglycemia
• D. Cardiac conduction changes (arrhythmias) and anticholinergic effects; monitoring in older adults

Answer: (D)

Tricyclic antidepressants carry two major risk streams: anticholinergic effects and effects on cardiac conduction. The anticholinergic impact comes from blocking muscarinic receptors, producing dry mouth, constipation, urinary retention, blurred vision, and tachycardia. In older adults, these effects can be particularly problematic, leading to delirium, confusion, cognitive decline, falls, and functional impairment, so careful monitoring and dose adjustments are often needed.

The cardiac conduction risks arise because TCAs also block sodium channels in the heart, which slows intraventricular conduction and can widen the QRS complex, raising the potential for arrhythmias. This danger is amplified in overdoses and in people with preexisting heart disease or electrolyte imbalances. For these reasons, especially in older adults who may have heart disease, clinicians monitor ECGs, vital signs, and symptoms, and take a cautious approach to dosing or consider alternatives.