Sugammadex: a novel selective relaxant binding agent.

Sugammadex, a modified γ-cyclodextrin, is the first selective relaxant binding agent. Sugammadex forms very tight complexes in a 1:1 ratio with steroidal neuromuscular blocking agents (rocuronium > vecuronium >> pancuronium). This guest-host complex, which exists in equilibrium, is stable because of its very high association rate and very low dissociation rate. Sugammadex has no effect on acetylcholinesterases or on any receptor system in the body, eliminating the need for anticholinergic drugs, which have undesirable adverse effects. Phase I-III trials found that sugammadex can antagonize any level of neuromuscular blockade, including the profound blockade induced by rocuronium, adding flexibility to the use of nondepolarizing relaxants. Sugammadex rapidly clears from most organs. Sugammadex in doses ranging from 2 to 16 mg/kg is recommended, depending of the level of rocuronium- or vecuronium-induced blockade. Common (incidence of 1-10%) adverse effects are similar for sugammadex and placebo, and include anesthetic complications (movement, coughing, grimacing or suckling on the tracheal tube) and cough. The US FDA has had concerns regarding the safety of sugammadex (hypersensitivity and allergic reactions), but upcoming international studies and the drug's widespread use in the EU will provide additional information.