Clinical pharmacology of atracurium in infants.
The neuromuscular effects of atracurium were studied in 25 infants anesthetized with 1.0% end-tidal halothane and N2O-O2. Neuromuscular blockade was monitored by recording the electromyographic activity of the adductor pollicis muscle resulting from supramaximal stimulation of the ulnar nerve at 2 Hz for 2 sec at 10-sec intervals. To estimate dose-response relationships, three groups of five infants received 60, 80, and 100 micrograms/kg atracurium, respectively; another ten infants received 300 micrograms/kg (2 X ED95). The neuromuscular block produced by 60 micrograms/kg was 27% +/- 10.9 (SEM), by 80 micrograms/kg was 34% +/- 8.0 and from 100 micrograms/kg was 70% +/- 8.3. The ED50 and ED95 (estimated from linear regression plots of log dose vs probit of effect) were 85 micrograms/kg and 150 micrograms/kg, respectively. Neuromuscular blockade lasted 23 +/- 1.6 min at 1 X ED95 and 32.5 +/- 5.2 min at 2 X ED95. Changes in heart rate and mean arterial pressure were clinically insignificant.
D000293:Adolescent; D000367:Age Factors; D000770:Anesthesia, Endotracheal; D001279:Atracurium; D001794:Blood Pressure / Q000187:drug effects; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007223:Infant; D007546:Isoquinolines / Q000494:pharmacology*; D009466:Neuromuscular Blocking Agents / Q000494:pharmacology*; D009469:Neuromuscular Junction / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects*
D007546:Isoquinolines; D009466:Neuromuscular Blocking Agents; D001279:Atracurium