title: Relative potency of some neuromuscular blocking drugs in vivo and in vitro.
abstract: The relative potencies of alcuronium, d-tubocurarine, gallamine, pancuronium and succinylcholine as neuromuscular blocking agents were tested in vivo (acute toxicity in mice) and in vitro (rat phrenic nerve-diaphragm preparation). In vivo, pancuronium was about 4 times more potent than alcuronium or d-tubocurarine, whose LD50-values were of the order of 2 X 10(-7) mol/kg. On a molar basis, succinylcholine was about 5 times less potent and gallamine about 20 times less potent than alcuronium or d-tubocurarine. In vitro, succinylcholine was as effective as d-tubocurarine and alcuronium. The IC50-values for these drugs were of the drugs were of the order of 2 X 10(-6)M. Pancuronium was about 2 times less potent and gallamine about 100 times less potent than the other three drugs in vitro. The in vivo-potencies correlate better than those obtained in vitro with observations from the clinical use of these muscle relaxants.
mesh_terms: D000443:Alcuronium / Q000494:pharmacology; D000818:Animals; D005703:Gallamine Triethiodide / Q000494:pharmacology; D007928:Lethal Dose 50; D008297:Male; D051379:Mice; D009466:Neuromuscular Blocking Agents / Q000494:pharmacology* / Q000633:toxicity; D010197:Pancuronium / Q000494:pharmacology; D010791:Phrenic Nerve / Q000187:drug effects; D051381:Rats; D013390:Succinylcholine / Q000494:pharmacology; D014403:Tubocurarine / Q000494:pharmacology
chemical_list: D009466:Neuromuscular Blocking Agents; D013390:Succinylcholine; D010197:Pancuronium; D005703:Gallamine Triethiodide; D000443:Alcuronium; D014403:Tubocurarine