Tricyclic Antidepressant (TCA) Overdose

A Traffic Control System Sabotaged Four Ways

Imagine a city's traffic system where four separate control stations manage flow. Station 1 (sodium channels in the heart) is like the traffic light timing system—normally it pulses in perfect rhythm to keep cars moving smoothly, but tricyclics gum up the timing mechanisms, so lights stay yellow too long and traffic crawls (wide QRS). Station 2 (acetylcholine receptors) is like the comfort and safety systems—normally they keep streetlights on, keep sidewalks clean, and keep public bathrooms open, but tricyclics shut them all off at once, leaving the city hot, dry, and chaotic (anticholinergic toxidrome). Station 3 (alpha-1 receptors on blood vessels) is like the pressure valves that keep water pressure steady in the pipes—tricyclics jam the valves open, so pressure drops citywide and won't recover with just more water (hypotension needing vasopressors). Station 4 (GABA receptors in the brain) is like the emergency brake system that prevents runaway trains—tricyclics disable the brakes, so the train (nerve firing) accelerates out of control and crashes (seizures). One poison, four sabotaged systems, one predictable disaster.