Hyperthyroidism patients have shorter onset and duration time of rocuronium than euthyroidism patients.

Purpose: The possibility of altered response to nondepolarizing muscle relaxants in hyperthyroidism patients has not been documented. The present study was conducted to observe the onset and duration of rocuronium induced neuromuscular blockade in hyperthyroidism patients.
Methods: Eighteen hyperthyroidism patients undergoing subtotal thyroidectomy (H group) and eighteen euthyroidism patients undergoing operation on neck (E group) were studied. Anesthetized with propofol and fentanyl, all patients received rocuronium 0.6 mg/kg. The twitch high of adductor pollicis muscle was monitored by acceleromyography. The onset, the duration of the initial dose, the durations of the repeated maintenance doses, the repeated times, and the total doses of rocuronium were observed.
Results: The onset time of rocuronium in H group was significantly shorter than that in E group (P<0.05). The duration of the initial dose as well as the durations of the repeated maintenance doses in H group was significantly shorter than that in E group (P<0.05). The repeated times and the total dosage of rocuronium in H group were significantly more than that in E group (P<0.05).
Conclusions: Hyperthyroidism patients experience a shorter onset time, a shorter duration, and require larger doses of rocuronium than euthyroidism patients.