Effects of two benzodiazepines and a benzodiazepine antagonist on neuromuscular blockade in the anaesthetized cat.
The interaction of diazepam and midazolam with non-depolarizing neuromuscular blocking drugs was studied in the sciatic nerve-tibialis anterior muscle preparation of the anaesthetized cat. Both diazepam and midazolam (0.3 mg/kg i.v.) caused a significant enhancement of a constant 50% neuromuscular block, produced by infusions of vecuronium or pancuronium. Increasing the dose of midazolam from 0.3 to 1.5 mg/kg, caused no significant further potentiation of vecuronium, but decreased the onset time of potentiation. Ro 15-1788, a selective benzodiazepine antagonist, did not antagonize the vecuronium potentiation caused by midazolam 0.3 mg/kg. However, when given before midazolam (1.5 mg/kg), Ro 15-1788 delayed the onset of potentiation. Ro 15-1788 antagonized and prevented the considerable blood pressure decrease produced by midazolam 0.3 and 1.5 mg/kg. There appears to exist a ceiling to the benzodiazepine-induced blood pressure decrease and potentiation of vecuronium in the cat.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats; D003975:Diazepam / Q000494:pharmacology*; D004347:Drug Interactions; D004357:Drug Synergism; D005260:Female; D005442:Flumazenil / Q000494:pharmacology*; D008297:Male; D008874:Midazolam / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009466:Neuromuscular Blocking Agents / Q000494:pharmacology*; D009469:Neuromuscular Junction / Q000187:drug effects*; D010197:Pancuronium / Q000494:pharmacology; D012584:Sciatic Nerve; D014673:Vecuronium Bromide / Q000494:pharmacology
D009466:Neuromuscular Blocking Agents; D005442:Flumazenil; D014673:Vecuronium Bromide; D010197:Pancuronium; D003975:Diazepam; D008874:Midazolam