title: Desflurane animal and human pharmacology: aspects of kinetics, safety, and MAC.
abstract: Substitution of fluorine for the single chlorine atom in isoflurane produces the new anesthetic, desflurane. This seemingly small change produces several pharmacologic changes. The potency of desflurane (MAC equals 6.0% in middle-aged patients) is one-fifth that of isoflurane (1.15%), with MAC for each agent decreased by aging, hypothermia, or the addition of depressants such as midazolam, fentanyl, or nitrous oxide. Some properties are similar: desflurane and isoflurane both depress respiration and neuromuscular contractility, and higher concentrations (e.g., 6%-8% desflurane) of both agents have a pungency that can provoke breath holding, laryngospasm, and salivation, particularly in infants and children. Of great importance, the substitution of fluorine for chlorine markedly decreases blood (desflurane blood-gas partition coefficient 0.42) and tissue solubility (e.g., brain-blood partition coefficient 1.3) relative to isoflurane (values 1.4 and 1.6, respectively). As a result, desflurane alveolar concentrations may be adjusted more rapidly and precisely; desflurane enters and leaves the lungs and tissues more rapidly; and recovery is quicker both for the short (first 10-20 min) and long (0.5-1.5 h) term. This greater precision of control and more rapid recovery are consistent with trends for new drug development in anesthesiology.
authors.affiliation: Department of Anesthesia, University of California, San Francisco 94143-0464.
authors.forename: E I
authors.initials: EI
authors.lastname: Eger
mesh_terms: D000769:Anesthesia, Inhalation; D000777:Anesthetics / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D000818:Animals; D000077335:Desflurane; D006801:Humans; D007530:Isoflurane / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000494:pharmacology; D012449:Safety
chemical_list: D000777:Anesthetics; D000077335:Desflurane; D007530:Isoflurane