BACKGROUND: Methoxycarbonyl etomidate is the prototypical soft etomidate analog. Because it has relatively low potency and is extremely rapidly metabolized, large quantities must be infused to maintain hypnosis. Consequently with prolonged infusion, metabolite reaches sufficient concentrations to delay recovery. Dimethyl-methoxycarbonyl metomidate (DMMM) and cyclopropyl-methoxycarbonyl metomidate (CPMM) are methoxycarbonyl etomidate analogs with higher potencies and slower clearance. Because of these properties, we hypothesized that dosing would be lower and electroencephalographic and hypnotic recoveries would be faster - and less context-sensitive - with DMMM or CPMM versus methoxycarbonyl etomidate or etomidate. METHODS: Etomidate, DMMM, and CPMM where infused into rats (n = 6 per group) for either 5 min or 120 min. After infusion termination, electroencephalographic and hypnotic recovery times were measured. The immobilizing ED50 infusion rates were determined using a tail clamp assay. RESULTS: Upon terminating 5-min infusions, electroencephalographic and hypnotic recovery times were not different among hypnotics. However, upon terminating 120-min infusions, recovery times varied significantly with respective values (mean ± SD) 48 ± 13 min and 31 ± 6.5 min (etomidate), 17 ± 7.0 min and 14 ± 3.4 min (DMMM), and 4.5 ± 1.1 min and 4.2 ± 1.6 min (CPMM). The immobilizing ED50 infusion rates were (mean ± SD) 0.19 ± 0.03 mg · kg · min (etomidate), 0.60 ± 0.12 mg · kg · min (DMMM), and 0.89 ± 0.18 mg · kg · min (CPMM). CONCLUSIONS: Electroencephalographic and hypnotic recoveries following prolonged infusions of DMMM and CPMM are faster than those following methoxycarbonyl etomidate or etomidate. In the case of CPMM infusion, recovery times are 4 min and context-insensitive.
BACKGROUND:Methoxycarbonyl etomidate is the prototypical soft etomidate analog. Because it has relatively low potency and is extremely rapidly metabolized, large quantities must be infused to maintain hypnosis. Consequently with prolonged infusion, metabolite reaches sufficient concentrations to delay recovery. Dimethyl-methoxycarbonyl metomidate (DMMM) and cyclopropyl-methoxycarbonyl metomidate (CPMM) are methoxycarbonyl etomidate analogs with higher potencies and slower clearance. Because of these properties, we hypothesized that dosing would be lower and electroencephalographic and hypnotic recoveries would be faster - and less context-sensitive - with DMMM or CPMM versus methoxycarbonyl etomidate or etomidate. METHODS:Etomidate, DMMM, and CPMM where infused into rats (n = 6 per group) for either 5 min or 120 min. After infusion termination, electroencephalographic and hypnotic recovery times were measured. The immobilizing ED50 infusion rates were determined using a tail clamp assay. RESULTS: Upon terminating 5-min infusions, electroencephalographic and hypnotic recovery times were not different among hypnotics. However, upon terminating 120-min infusions, recovery times varied significantly with respective values (mean ± SD) 48 ± 13 min and 31 ± 6.5 min (etomidate), 17 ± 7.0 min and 14 ± 3.4 min (DMMM), and 4.5 ± 1.1 min and 4.2 ± 1.6 min (CPMM). The immobilizing ED50 infusion rates were (mean ± SD) 0.19 ± 0.03 mg · kg · min (etomidate), 0.60 ± 0.12 mg · kg · min (DMMM), and 0.89 ± 0.18 mg · kg · min (CPMM). CONCLUSIONS: Electroencephalographic and hypnotic recoveries following prolonged infusions of DMMM and CPMM are faster than those following methoxycarbonyl etomidate or etomidate. In the case of CPMM infusion, recovery times are 4 min and context-insensitive.
Authors: Joseph F Cotten; S Shaukat Husain; Stuart A Forman; Keith W Miller; Elizabeth W Kelly; Hieu H Nguyen; Douglas E Raines Journal: Anesthesiology Date: 2009-08 Impact factor: 7.892
Authors: P L C van den Broek; C M van Rijn; J van Egmond; A M L Coenen; L H D J Booij Journal: Eur J Anaesthesiol Date: 2006-02-10 Impact factor: 4.330
Authors: Raymond J Malapero; Michael P Zaccagnino; Ethan Y Brovman; Alan David Kaye; Richard D Urman Journal: J Anaesthesiol Clin Pharmacol Date: 2017 Oct-Dec