A Randomized, Dose-Finding, Phase II Study of the Selective Relaxant Binding Drug, Sugammadex, Capable of Safely Reversing Profound Rocuronium-Induced Neuromuscular Block

In Brief BACKGROUND: The reversal of a deep neuromuscular blockade remains a significant clinical problem. Sugammadex, a modified γ-cyclodextrin, encapsulates steroidal neuromuscular blocking drugs, promoting their rapid dissociation from nicotinic receptors. Sugammadex is the first drug that acts as a selective relaxant binding agent. METHODS: We enrolled 50 patients into a Phase II dose-finding study of the efficacy and safety of sugammadex. Subjects, anesthetized with nitrous oxide and propofol, were randomized to one of two doses of rocuronium (0.6 or 1.2 mg/kg) and to one of five doses of sugammadex (0.5, 1.0, 2.0, 4.0, or 8.0 mg/kg). Neuromuscular monitoring was performed using the TOF Watch SX® acceleromyograph. Recovery was defined as a train-of-four ratio ≥0.9. Sugammadex was administered during profound block when neuromuscular monitoring demonstrated a posttetanic count of one or two. RESULTS: Reversal of neuromuscular block was obtained after administration of sugammadex in all but the lowest dose groups (0.5–1.0 mg/kg) where several subjects could not be adequately reversed. At the 2 mg/kg dose all patients were reversed with sugammadex, but there was significant variability (1.8–15.2 min). Patient variability decreased and speed of recovery increased in a dose-dependent manner. At the highest dose (8 mg/kg), mean recovery time was 1.2 min (range 0.8–2.1 min). No serious adverse events were reported during this trial. CONCLUSIONS: Sugammadex was well tolerated and effective in rapidly reversing profound rocuronium-induced neuromuscular block. The mean time to recovery decreased with increasing doses. Profound rocuronium-induced neuromuscular block can be reversed successfully with sugammadex at doses ≥2 mg/kg. IMPLICATIONS: This study examined the safety, dosing, and efficacy of the first selective relaxant binding agent, sugammadex. Sugammadex can safely and quickly reverse a profound rocuronium-induced, neuromuscular block. The drug was well tolerated by all subjects. The speed of complete recovery (T4/T1ratio of 0.9) was dose dependent. A dose of 2 mg/kg of sugammadex consistently produced complete recovery from deep neuromuscular block.