Rapacuronium

A non-depolarizing neuromuscular blocking agent

Rapacuronium
INN
Drug class
Routes of administration	Intravenous
Pregnancy category
Bioavailability	N/A
Metabolism	Hepatic
Elimination half-life	2 hours
Excretion	Renal
Legal status	Withdrawn
CAS Number	156799-94-5
PubChem	6918314
DrugBank	DB04834
ChemSpider	5293500
KEGG	D08410

Rapacuronium, marketed under the trade name Raplon, is a non-depolarizing neuromuscular blocking agent that was used in anesthesia to induce muscle relaxation during surgery or mechanical ventilation. It was introduced as a rapid-onset, short-duration alternative to other neuromuscular blockers. However, due to safety concerns, it was withdrawn from the market.

Pharmacology

Rapacuronium is a quaternary ammonium compound that acts as a competitive antagonist at the nicotinic acetylcholine receptor at the neuromuscular junction. By blocking the action of acetylcholine, it prevents depolarization of the muscle cell membrane, leading to muscle relaxation.

Mechanism of Action

Rapacuronium binds to the nicotinic acetylcholine receptors on the motor end plate of the neuromuscular junction, preventing acetylcholine from binding and activating the receptor. This inhibition prevents the depolarization of the muscle cell membrane, thereby inhibiting muscle contraction.

Pharmacokinetics

Rapacuronium is administered intravenously and has a rapid onset of action, typically within 1 to 2 minutes. It is metabolized in the liver and has a relatively short elimination half-life of approximately 2 hours. The drug is primarily excreted via the kidneys.

Clinical Use

Rapacuronium was used to facilitate tracheal intubation and provide muscle relaxation during surgery or mechanical ventilation. Its rapid onset and short duration made it a preferred choice in situations requiring quick muscle relaxation.

Safety and Withdrawal

Rapacuronium was withdrawn from the market due to reports of severe bronchospasm and other respiratory complications. These adverse effects were significant enough to outweigh the benefits of its rapid onset and short duration of action.

Also see

• Neuromuscular-blocking drug
• Anesthesia
• Acetylcholine
• Nicotinic acetylcholine receptor