indication

For use as a skeletal muscle relaxant

pharmacology

Decamethonium acts as a depolarizing muscle relaxant or neuromuscular blocking agent. It acts as an agonist of nicotinic acetycholine receptors in the motor endplate and causes depolarization. This class of drugs has its effect at the neuromuscular junction by preventing the effects of acetylcholine. Normally, when a nerve stimulus acts to contract a muscle, it releases acetylcholine. The binding of this acetylcholine to receptors causes the muscle to contract. Muscle relaxants play an important role in anesthesia even though they don't provide any pain relief or produce unconsciousness.

mechanism of action

Binds to the nicotinic acetycholine receptors (by virtue of its similarity to acetylcholine) in the motor endplate and blocks access to the receptors. In the process of binding, the receptor is actually activated - causing a process known as depolarization. Since it is not degraded in the neuromuscular junction, the depolarized membrance remains depolarized and unresponsive to any other impulse, causing muscle paralysis.

toxicity

LD₅₀=190 mg/kg (orally in mice). Prolonged apnoea, neuromuscular paralysis and cardiac arrest may occur.

absorption

Rapidly absorbed.