indication

Primarily used in the treatment of glaucoma, but is also used during ophthalmic surgery.

pharmacology

Carbachol is a potent cholinergic (parasympathomimetic) agent which produces constriction of the iris and ciliary body resulting in reduction in intraocular pressure. The exact mechanism by which carbachol lowers intraocular pressure is not precisely known. In the cat and rat, carbachol is well-known for its ability to induce rapid eye movement (REM) sleep when microinjected into the pontine reticular formation. Carbachol elicits this REM sleep-like state via activation of postsynaptic muscarinic cholinergic receptors (mAChRs).

mechanism of action

Carbachol is a parasympathomimetic that stimulates both muscarinic and nicotinic receptors. In topical ocular and intraocular administration its principal effects are miosis and increased aqueous humour outflow.

toxicity

Oral, mouse: LD₅₀ = 15 mg/kg; Oral, rat: LD₅₀ = 40 mg/kg.

absorption

Not well absorbed in the gastro-intestinal tract, and does not cross the blood-brain barrier.