Reversal of rocuronium-induced neuromuscular block by sugammadex is independent of renal perfusion in anesthetized cats.

PURPOSE: Sugammadex is a selective relaxant binding agent designed to encapsulate the aminosteroidal neuromuscular blocking agent rocuronium, thereby reversing its effect. Both sugammadex and the sugammadex-rocuronium complex are eliminated by the kidneys. This study investigated the effect of sugammadex on recovery of rocuronium-induced neuromuscular block in cats with clamped renal pedicles, as a model for acute renal failure. METHODS: Twelve male cats were divided into two groups and anesthetized with medetomidine, ketamine, and alpha-chloralose. The cats were intubated and ventilated with a mixture of oxygen and air. Neuromuscular monitoring was performed by single twitch monitoring. Rocuronium 0.5 mg/kg i.v. was administered. After spontaneous recovery from neuromuscular block, both renal pedicles were ligated. A second dose of rocuronium 0.5 mg/kg i.v. was given. One minute after disappearance of the twitches, in Group 1 placebo (0.9% saline) and in Group 2 sugammadex 5.0 mg/kg i.v. was administered. Onset time, duration of neuromuscular block, and time to recovery to 25, 50, 75, and 90% were determined. RESULTS: After renal pedicle ligation, sugammadex reversed rocuronium-induced neuromuscular block significantly faster than spontaneous recovery. Mean time (SEM) to 90% recovery of the twitch response was 4.7 (0.25) min (Group 2) versus 31.1 (5.0) min (Group 1) (p < 0.0001). No signs of recurrence of neuromuscular block were observed for 90 min after complete twitch restoration. Sugammadex caused no significant cardiovascular effects. CONCLUSION: Sugammadex rapidly and effectively reversed rocuronium-induced neuromuscular block in anesthetized cats, even when both renal pedicles were ligated and renal elimination of the drugs was no longer possible.

Sugammadex reverses neuromuscular block induced by 3-desacetyl-vecuronium, an active metabolite of vecuronium, in the anaesthetised rhesus monkey.

BACKGROUND AND OBJECTIVE: 3-Desacetyl-vecuronium is an active metabolite of the neuromuscular blocking agent (NMBA) vecuronium, which might lead to residual paralysis after prolonged administration of vecuronium in critically ill patients with renal failure. This study investigated the ability of sugammadex to reverse 3-desacetyl-vecuronium-induced neuromuscular block (NMB) in the anaesthetised rhesus monkey. METHODS: Experiments were performed in anaesthetised female rhesus monkeys. After bolus intravenous injection of vecuronium (n = 8) or 3-desacetyl-vecuronium (n = 8) 10 µg kg(-1) (ED90), a continuous infusion of the same NMBA was started to maintain the first twitch of the train-of-four (TOF) at 10% of baseline value. The infusion was stopped and NMB recovered spontaneously. The procedure was repeated, but immediately after stopping the infusion, an intravenous bolus dose of sugammadex 0.5 or 1.0 mg kg(-1) was given. For each NMBA, four placebo experiments were performed, in which the second recovery from NMB was also spontaneous. For all experiments, time to recovery of the TOF ratio to 90% was retrieved. RESULTS: After administration of sugammadex for reversal of 3-desacetyl-vecuronium-induced NMB, recovery was significantly faster than spontaneous recovery. Mean time to recovery of TOF to 90% was 3.2 min (sugammadex 0.5 mg kg(-1)) and 2.6 min (1.0 mg kg(-1)), compared to spontaneous recovery (17.6 min). For vecuronium-induced NMB, mean time to recovery of TOF to 90% was 17.1 min (0.5 mg kg(-1)) and 4.6 min (1.0 mg kg(-1)), compared to spontaneous recovery (23.4 min). CONCLUSION: Sugammadex rapidly and effectively reversed 3-desacetyl-vecuronium-induced NMB in the rhesus monkey, at a lower dose than that needed to reverse vecuronium-induced NMB.

Preclinical pharmacology of sugammadex.

Since the introduction of nondepolarizing neuromuscular blocking agents, acetylcholinesterase inhibitors have been used to increase the speed of recovery from neuromuscular blockade. The major disadvantages of acetylcholinesterase inhibitors are their lack of activity against profound neuromuscular blockade and their activity outside the neuromuscular junction resulting in unwanted side effects, requiring cotreatment with a muscarinic antagonist. An alternative to acetylcholinesterase inhibitors is the encapsulating agent sugammadex. This agent has been specifically designed to encapsulate the steroidal neuromuscular blocking agents rocuronium and vecuronium. This review describes the effects of sugammadex in in vitro tissue and in vivo animal experiments. The encapsulation approach allows reversal of any degree of neuromuscular blockade because the dose of sugammadex can be adjusted to encapsulate sufficient neuromuscular blocking molecules to cause effective reversal. Because this interaction is a drug-drug interaction, reversal can be achieved very fast but is limited by the circulation time. Sugammadex is also effective against neuromuscular blockade under conditions with reduced acetylcholine release, which potentiate the action of neuromuscular blocking agents. Sugammadex does not cause cholinergic side effects, preventing the need of coadministration of muscarinic antagonists. Because of these properties, sugammadex has the potential to become a very useful drug for the management of neuromuscular blockade.

Selective relaxant binding agents for reversal of neuromuscular blockade.

Traditionally, reversal of neuromuscular blockade during anaesthesia was achieved by increasing the acetylcholine concentration in the neuromuscular junction using acetylcholinesterase inhibitors. However, this is ineffective against profound blockade. Furthermore, the increase in acetylcholine level is not limited to the neuromuscular junction, resulting in unwanted side effects requiring co-treatment with muscarinic antagonists. Selective relaxant binding agents offer a new approach for the reversal of neuromuscular blockade: encapsulation of the neuromuscular blocking agent, resulting in inactivation. As part of this new approach, cyclodextrin molecules have been designed that selectively encapsulate steroidal neuromuscular blocking agents. Both animal and human experiments have demonstrated that fast, effective and complete recovery from both normal and profound neuromuscular blockade is now possible. Furthermore, these cyclodextrin derivatives do not have the unwanted side effects of acetylcholinesterase inhibitors.

Synthesis and evaluation of N-3 substituted phenoxypropyl piperidine benzimidazol-2-one analogues as NOP receptor agonists with analgesic and sedative properties.

A series of 3-phenoxypropyl piperidine benzimidazol-2-one analogues have been discovered as novel NOP receptor agonists. Structure-activity relationships have been explored via N-3 substitution of the benzimidazol-2-one with a range of functionality. The N-methyl acetamide derivative (+)-7f was found to be a high-affinity, potent NOP agonist with greater than 100-fold selectivity over the MOP receptor. Furthermore (+)-7f was shown to be both antinociceptive and sedative when administered iv to rodents.

Reversal of profound rocuronium neuromuscular blockade by sugammadex in anesthetized rhesus monkeys.

BACKGROUND: Reversal of neuromuscular blockade can be accomplished by chemical encapsulation of rocuronium by sugammadex, a synthetic gamma-cyclodextrin derivative. The current study determined the feasibility of reversal of rocuronium-induced profound neuromuscular blockade with sugammadex in the anesthetized rhesus monkey using train-of-four stimulation. METHODS: Four female rhesus monkeys each underwent three experiments. In each experiment, first, a 100-microg/kg dose of rocuronium was injected and spontaneous recovery was monitored. After full recovery, a 500-microg/kg dose of rocuronium was injected. Up to this point, all three experiments in a single monkey were identical. One minute after this rocuronium injection, either one of the two tested dosages of sugammadex (1.0 or 2.5 mg/kg) was injected or saline was injected. RESULTS: Injection of 100 microg/kg rocuronium resulted in a mean neuromuscular blockade of 93.0% (SD = 4%), and profound blockade was achieved by injection of 500 microg/kg. In all experiments, a 100% neuromuscular blockade was achieved at this dose. After injection of the high rocuronium dose, the 90% recovery of the train-of-four ratio took 28 min (SD = 7 min) after saline, 26 min (SD = 9.5 min) after 1 mg/kg sugammadex, and 8 min (SD = 3.6 min) after 2.5 mg/kg sugammadex. Signs of residual blockade or recurarization were not observed. Injection of sugammadex had no significant effects on blood pressure or heart rate. CONCLUSIONS: Chemical encapsulation of rocuronium by sugammadex is a new therapeutic mechanism allowing effective and rapid reversal of profound neuromuscular blockade induced by rocuronium in anesthetized rhesus monkeys.

Reversal of neuromuscular blockade and simultaneous increase in plasma rocuronium concentration after the intravenous infusion of the novel reversal agent Org 25969.

BACKGROUND: The purpose of this study was to determine the changes in the plasma concentration of rocuronium and the reversal of its neuromuscular blockade after the intravenous infusion of Org 25969, the novel neuromuscular block-reversal agent, in anesthetized guinea pigs. METHODS: Rocuronium was infused for 1 h at a rate of 12-19 nmol.kg-1.min-1 to produce a steady-state 90% neuromuscular block. After 30 min, a concomitant infusion of either the reversal agent Org 25969 at a rate of 50 nmol.kg-1.min-1 or an infusion of an equivalent volume of saline was started. The time course of plasma concentrations of rocuronium was determined by use of liquid chromatography-mass spectrometry/mass spectrometry. RESULTS: In both treatment groups, a steady-state plasma concentration of rocuronium was obtained after 30 min. In the saline-treated group, the plasma concentration of rocuronium and depth of block remained constant. In the Org 25969 group, neuromuscular block was reversed while the rocuronium infusion was ongoing. Simultaneously, an increase in the total plasma concentration of rocuronium (free and complexed) was observed, even though the infusion rate of rocuronium was not changed. Compared with the saline-treated group, a small increase in the postmortem bladder concentration of rocuronium was detected. CONCLUSIONS: The authors propose that the capture of rocuronium by Org 25969 causes the rapid reversal of neuromuscular block. The reversal can be explained by the rapid transfer of free rocuronium from the effect compartment (neuromuscular junction) to the central compartment, in which it is bound to Org 25969. This explains the increase in total plasma concentration of rocuronium (free and bound to Org 25969).

2-O-substituted cyclodextrins as reversal agents for the neuromuscular blocker rocuronium bromide.

A series of secondary face modified cyclodextrins (CDs) were synthesised with the aim of constructing host molecules capable of forming host-guest complexes with neuromuscular blockers, especially with rocuronium bromide. Perfacial 2-O-substitution of gamma-CD with 4-carboxybenzyl resulted in a CD host molecule 1 that forms a 1:1 binary complex with rocuronium bromide (K(a) 6.2 x 10(5) M(-1)). The biological activities of this compound and other derivatives as reversal agents of rocuronium bromide were examined in vitro (mouse hemi-diaphragm) and in vivo (anaesthetized guinea pigs). The host molecule 1 was found to exert potent reversal activity (ED(50) 0.21 micromol/kg, iv) against rocuronium-induced neuromuscular block, and thus proved the viability of using host molecules as antidotes of a biologically active compound.

Cyclodextrin-derived host molecules as reversal agents for the neuromuscular blocker rocuronium bromide: synthesis and structure-activity relationships.

A series of mono- and per-6-substituted cyclodextrin derivatives were synthesized as synthetic receptors (or host molecules) of rocuronium bromide, the most widely used neuromuscular blocker in anaesthesia. By forming host-guest complexes with rocuronium, these cyclodextrin derivatives reverse the muscle relaxation induced by rocuronium in vitro and in vivo and therefore can be used as reversal agents of the neuromuscular blocker to assist rapid recovery of patients after surgery. Because this supramolecular mechanism of action does not involve direct interaction with the cholinergic system, the reversal by these compounds, e.g., compound 14 (Org 25969), is not accompanied by cardiovascular side effects usually attendant with acetylcholinesterase inhibitors such as neostigmine. The structure-activity relationships are consistent with this supramolecular mechanism of action and are discussed herein. These include the effects of binding cavity size and hydrophobic and electrostatic interaction on the reversal activities of these compounds.

New approaches to reversal of neuromuscular block.

Although numerous reversal agents for neuromuscular block (NMB) have been known for some time, investigations on new approaches were initiated only recently. The different approaches used in an attempt to avoid the muscarinic side effects associated with the antagonists of NMB that are currently available are reviewed.