Cumulative dose-response curves for atracurium in patients with myasthenia gravis.
The potency of atracurium was determined in five patients with moderate to severe generalized myasthenia gravis undergoing thymectomy. Train-of-four stimulation was applied to the ulnar nerve and the force of contraction of the adductor pollicis was measured. Cumulative dose-response curves were obtained during thiopentone-nitrous oxide-fentanyl anaesthesia. The average time to complete the dose-response studies was 12.7 +/- 1.5 minutes. The ED50, ED90 and ED95 of atracurium were (mean +/- SEM) 0.07 +/- 0.01, 0.12 +/- 0.22, and 0.14 +/- 0.04 mg.kg-1, respectively. The time to 25 per cent first twitch recovery was 35 +/- 4 min following maximum blockade. Ten normal patients were studied in the same manner. Their ED50, ED90 and ED95 were 0.13 +/- 0.01, 0.21 +/- 0.02 and 0.24 +/- 0.03 mg.kg-1, respectively. These results demonstrated that, in patients with moderate to severe generalized myasthenia gravis, atracurium was 1.7-1.9 times as potent as in normal individuals.
Department of Anaesthesia, Royal Victoria Hospital, Montreal, Canada.
C E
CE
Smith
F
F
Donati
D R
DR
Bevan
D000328:Adult; D000769:Anesthesia, Inhalation; D001279:Atracurium / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000601:surgery*; D013934:Thymectomy
D001279:Atracurium