title: Comparison of physostigmine and neostigmine for antagonism of neuromuscular block.
abstract: The ability of physostigmine alone and in combination with neostigmine to reverse d-tubocurarine-induced neuromuscular block was evaluated in surgical patients. The relaxation was maintained at a level of 90% twitch suppression during balanced anesthesia, and antagonism was attempted with physostigmine 1.5 mg x 3; neostigmine 0.5 mg x 3; neostigmine 1.0 mg x 3; or with a combination of physostigmine 0.75 mg and neostigmine 0.5 mg x 3. The measured parameters included the twitch force or EMG amplitude of the adductor pollicis brevis muscle after supramaximal 0.1 Hz stimulation and fading of these responses after repetitive 2 and 50 Hz stimuli. Although the restitution rate of twitch height and EMG amplitude were essentially the same with both antagonists, there was a considerable time-lag in regeneration of the fades after repetitive stimuli with physostigmine as compared with the neostigmine group. The addition of physostigmine to a subeffective dose of neostigmine resulted in antagonism comparable to that seen in other groups. The clinical antagonism was satisfactory in all patients receiving physostigmine. The divergence of relaxation-indicating parameters (twitch responses and fades) after physostigmine suggests dissimilar modes of action of two antagonists at the neuromuscular junction.
mesh_terms: D000328:Adult; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D009388:Neostigmine / Q000494:pharmacology*; D009466:Neuromuscular Blocking Agents / Q000037:antagonists & inhibitors*; D010830:Physostigmine / Q000494:pharmacology*; D011229:Preanesthetic Medication
chemical_list: D009466:Neuromuscular Blocking Agents; D009388:Neostigmine; D010830:Physostigmine