Atracurium

Atracurium binds competitively to nicotinic receptors on the motor end-plate. It is inactivated in plasma by Hofmann elimination, a spontaneous non-enzymatic breakdown at body pH and temperature, and by ester hydrolysis, so neither liver nor kidney plays a major part. Its metabolite laudanosine has no blocking action but can excite the brain at high levels in animals.

Like other non-depolarizing neuromuscular blockers: These drugs bind competitively to the nicotinic acetylcholine receptors of the motor end-plate, so acetylcholine cannot trigger muscle contraction and skeletal muscle is paralyzed. They have no effect on consciousness or pain. Anticholinesterases such as neostigmine, given with atropine or glycopyrrolate, reverse the block by raising acetylcholine; sugammadex reverses rocuronium by binding the drug itself.

• Histamine release is more likely with large or fast doses: take care in asthma and heart disease.
• It is acidic: do not mix it with alkaline solutions such as barbiturates, and never give it IM.
• Myasthenia gravis and Eaton-Lambert syndrome greatly increase its effect; burns can cause resistance.
• Always give it with adequate anesthesia, with airway support and reversal agents ready.

Good to know: Its organ-independent breakdown suits patients with liver or kidney failure, and its action is not tied to plasma cholinesterase levels.

Easily mixed up with depolarizing neuromuscular blockers and anticholinesterases.