Korean J Anesthesiol.  1995 Jun;28(6):816-820. 10.4097/kjae.1995.28.6.816.

Comparison of Pharmacokinetic Affinity of Various Non-depolarizing Neuromuscular Blocking Agents in the Isolated Foream

• Lee SK
• Jeon YS
• Ahn JS
• Hwang KH
• Park W
• Kim SY

• KMID: 2013189
• DOI: http://doi.org/10.4097/kjae.1995.28.6.816

Abstract

It is well known that the plasma concentration is important in determining the rate of recovery from neuromuscular block. However, nondepolarizing neuromuscular blockade are retained at the neuromuscular junction and are not readily displaced in response of changes in plasma drug concentration, for instance, the neuromuscular block induced by mivacurium appears to considerably outlast the theoretical plasma half-life of the drug and is continued long after the plasma level has fallen to subparalytic levels due to rapid metabolism by pseudocholinesterase. It has been suggested that although plasma concentration may be the key determinant of recovery from neuromuscular block, recovery will depend upon the dissociation from the affinity of drug in the effect compartrnent and not upon its plasma concentration. In an attempt to confirm these evidences, we have investigated the response of changes in neuromuscular block after releasing tourniquet at 50% twitch depression using the isolated forearm experiment with various neuromuscular blocking agents. The results of this study demonstrated the further increase of block after early toumiquet release in the isolated forarm in all agents; 66+/-14% in vecuronium, 90+/-9% in atracurium, 92+/-7% in pancuronium, and 73+/-18% in mivacurium Conclusively, the further block continued to increase in spite of the negligible plasma drug concentration after early tourniquet release may be caused by more in affinity of drugs in binding sites than plasma drug concentration. Therfore, it is evident that both the affinity of drug to the receptor and the plasma drug concentration have influenced on the recovery from the neuromuscular block.

Keyword

Nondepolarizing neuromuscular blocking agent; Isolated forearm test

MeSH Terms

Atracurium
Binding Sites
Depression
Forearm
Half-Life
Metabolism
Neuromuscular Blockade*
Neuromuscular Blocking Agents*
Neuromuscular Junction
Pancuronium
Plasma
Pseudocholinesterase
Tourniquets
Vecuronium Bromide
Atracurium
Neuromuscular Blocking Agents
Pancuronium
Pseudocholinesterase
Vecuronium Bromide