ATC Group: M03A Muscle relaxants, peripherally acting agents

Atracurium besilate is a non-depolarising neuromuscular blocking agent with an intermediate duration of action, administered intravenously to produce skeletal muscle relaxation.

Botulinum toxin type A is a protein complex derived from Clostridium botulinum. The protein consists of type A neurotoxin and several other proteins. Under physiological conditions it is presumed that the complex dissociates and releases the pure neurotoxin. Intramuscular injection of the neurotoxin complex blocks cholinergic transport at the neuromuscular junction by preventing the release of acetylcholine. The nerve endings of the neuromuscular junction no longer respond to nerve impulses and secretion of the chemotransmitter is prevented (chemical denervation).

Botulinum toxin type B is a neuromuscular blocking agent indicated for the treatment of cervical dystonia. When injected directly into a muscle, it causes a localised paralysis that gradually reverses over time.

Cisatracurium is an intermediate-duration, non-depolarising benzylisoquinolinium skeletal muscle relaxant. Cisatracurium binds to cholinergic receptors on the motor end-plate to antagonise the action of acetylcholine, resulting in a competitive block of neuromuscular transmission. This action is readily reversed by anti-cholinesterase agents such as neostigmine or edrophonium.

Pancuronium produces pharmacologic effects similar to those of other non-depolarising neuromuscular blocking agents. The drug may produce an increase in heart rate which appears to result from a direct blocking effect on the acetylcholine receptors of the heart. Pancuronium causes little or no histamine release and no ganglionic blockade and therefore does not cause hypotension or bronchospasm.

Rocuronium is a fast onset, intermediate acting non-depolarising neuromuscular blocking agent, possessing all of the characteristic pharmacological actions of this class of medicinal products (curariform agents). It acts by competing for nicotinic cholinoceptors at the motor end-plate.

Suxamethonium is a short-acting depolarising neuromuscular blocking agent. Suxamethonium inhibits neuromuscular transmission by depolarising the motor end plates in skeletal muscle.

Vecuronium is a non-depolarising neuromuscular blocking agent. Vecuronium blocks the transmission process between the motor nerve-ending and striated muscle by binding competitively with acetylcholine to the nicotinic receptors located in the motor end-plate region of striated muscle.