Muscle relaxant

In medicine, a muscle relaxant is a drug that causes skeletal muscle contraction to cease. Muscle relaxants are used to facilitate surgery, to enable tracheal intubation and to facilitate mechanical ventilation.

Muscles relaxants typically work by blocking the effect of acetylcholine (ACh) at the neuromuscular junction.

Table of contents

1 Receptor blockers 2 Other mechanisms 3 Central acting muscle relaxants 4 Acting on smooth muscle

Receptor blockers

Substances that compete with ACh, for the receptors on a muscle cell can be either depolarising, or non-depolarising.

Depolarising muscles relaxants activate the muscle briefly, before blocking it.

• Succinylcholine

Non-depolarising relaxants block the ACh receptors without activating them.

• Curare
• Curare-based molecules, e.g. turbocuranine, pancuronium bromide.

Other mechanisms

Botulinum toxin, marketed as Botox for facial wrinkle removal, works by stopping the release of ACh from the presynaptic neuron.

Central acting muscle relaxants

• Benzodiazepines

Acting on smooth muscle

• Amyl nitrite