Pharmacodynamics of rocuronium with and without prior administration of succinylcholine

To compare succinylcholine (S) and rocuronium (R) used for endotracheal intubation, and to assess the possible action of S on subsequently administered R.

Double-blind, randomized, phase III study.

University Medical Center.

24 ASA physical status I and II patients, ages 28 to 65, undergoing general anesthesia for abdominal procedures.

Double-blind administration of R 600 mcg/kg (Group A) or S 1 mg/kg was achieved with open label R 150 mcg/kg. Standardized general anesthetic technique with sodium thiopental, fentanyl, and nitrous oxide in oxygen was administered.

Neuromuscular junction was tested by ulnar nerve stimulation and mechanomyograph. Intubation was attempted at 80% first twitch depression of train-of-four. Heart rate and blood pressure were recorded throughout. Onset times were 74 +/- 37 seconds for S and 130 +/- 46 seconds for R. Intubation times were 76 +/- 29 seconds for S and 85 +/- 23 seconds for R (no significant difference). Good to excellent intubation conditions were achieved in both groups. S given prior to R decreased onset time and increased duration of R, when compared with R given alone. No drug related cardiovascular events were noted.

Rapid intubation conditions can be obtained after both S and R. Given its overall safety profile, R can be used when S is contraindicated, or in healthy patients with no apparent difficult airway, when procedures are expected to last more than 25 minutes.