title: The pharmacology of cyclopropyl-methoxycarbonyl metomidate: a comparison with propofol.
abstract: BACKGROUND
  Cyclopropyl-methoxycarbonyl metomidate (CPMM) is a "soft" etomidate analogue currently being developed as a propofol alternative for anesthetic induction and maintenance.
  
  
  METHODS
  We compared the potencies of CPMM and propofol by assessing their abilities to directly activate α1(L264T)β3γ2 gamma-aminobutyric acid type A (GABAA) receptors and induce loss of righting reflexes in tadpoles. We also measured the rates of encephalographic recovery in rats after CPMM and propofol infusions ranging in duration from 5 to 120 minutes.
  
  
  RESULTS
  CPMM and propofol activate GABAA receptors and induce loss of righting reflexes in tadpoles with respective 50% effective concentrations (EC50s) of 3.8 ± 0.4 and 3.9 ± 0.2 μM (GABAA receptor) and 2.6 ± 0.19 and 1.3 ± 0.04 μM (tadpole). Encephalographic recovery after prolonged infusion was faster with CPMM and lacked propofol's context sensitivity.
  
  
  CONCLUSIONS
  CPMM and propofol have similar potencies in GABAA receptors and tadpoles; however, CPMM provides more rapid and predictable recovery than propofol, particularly after prolonged infusion.
authors.affiliation: From the *Department of Anesthesia, Perioperative and Pain Medicine, Boston Children's Hospital; †Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts; and ‡Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Rile
authors.initials: R
authors.lastname: Ge
authors.forename: Ervin
authors.initials: E
authors.lastname: Pejo
authors.forename: Hilary
authors.initials: H
authors.lastname: Gallin
authors.forename: Spencer
authors.initials: S
authors.lastname: Jeffrey
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Cotten
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Raines
mesh_terms: D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D004569:Electroencephalography / Q000187:drug effects / Q000379:methods; D005045:Etomidate / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D007814:Larva; D008297:Male; D015742:Propofol / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000378:metabolism; D057897:Reflex, Righting / Q000187:drug effects / Q000502:physiology; D014982:Xenopus laevis
chemical_list: D018686:Anesthetics, Intravenous; D011963:Receptors, GABA-A; D015742:Propofol; C084586:metomidate; D005045:Etomidate