Anesthetics volatile

Inhaled anesthetics Volatile liquids Halothane Enflurane, desflurane, isoflurane, methoxyflurane, sevoflurane... 

Although most anesthetics are achiral or are adininistered as racemic mixture, the anesthetic actions are stereoselective. This property can define a specific, rather than a nonspecific, site of action. Stereoselectivity is observed for such barbiturates as thiopental, pentobarbital, and secobarbital. The (3)-enantiomer is modestly more potent (56,57). Additionally, the volatile anesthetic isoflurane also shows stereoselectivity. The (3)-enantiomer is the more active (58). Further evidence that proteins might serve as appropriate targets for general anesthetics come from observations that anesthetics inhibit the activity of the enzyme luciferase. The potencies parallel the anesthetic activities closely (59,60). 

Flurothyl [333-36-8] (bis-(2,2,2-trifluoroeth5i)ether) (9), an analeptic having strong convulsant properties, has been used for chemical shock therapy (13). The compound is unique in that it is a volatile fluorinated ether and its stmcture resembles those of many halogenated general anesthetics. Chemical shock therapy is rarely used. 

Parent substances and metaboHtes may be stored in tissues, such as fat, from which they continue to be released following cessation of exposure to the parent material. In this way, potentially toxic levels of a material or metaboHte may be maintained in the body. However, the relationship between uptake and release, and the quantitative aspects of partitioning, may be complex and vary between different materials. For example, volatile lipophilic materials are generally more rapidly cleared than nonvolatile substances, and the half-Hves may differ by orders of magnitude. This is exemplified by comparing halothane and DDT (see Anesthetics Insectcontholtechnology). 

Halothane and methoxyflurane are volatile and are used in a vaporizer and deflvered to the animal via an oxygen carrier. Both agents can be dehvered with nitrous oxide [14522-82-8], a mild anesthetic that when combined with halothane or methoxyflurane can induce anesthesia faster than... 

Toxicity. 1,1-Dichloroethane, like all volatile chlorinated solvents, has an anesthetic effect and depresses the central nervous system at high vapor concentrations. The 1991 American Conference of Governmental Industrial Hygienists (ACGIH) recommends a time-weighted average (TWA) solvent vapor concentration of 200 ppm and a permissible short term exposure level (STEL) of 250 ppm for worker exposure. The oral LD q of... 

Diethyl ether [60-29-7] is one of the more important members of the ether family. It is a colorless, very volatile, highly flammable Hquid with a sweet, pungent odor and burning taste. As a commercial product it is available in several grades it is used in chemical manufacture, as a solvent, extractant, or reaction medium, and as a general anesthetic. 

Gas chromatography (GC) has also been used for preparative purposes, but is restricted to relatively volatile racemates such as anesthetics, pheromones or monoterpenes and, therefore, very few applications are reported. Nevertheless, in the cases to which GC may be applied, it could be considered as an economical alternative to HPLC. Most of the resolutions of enantiomers were performed on cyclodex-trin-derived CSPs [109, 144-153], and only on very few occasions were other chiral selectors used [153]. 

The anesthesiologist selects the anesthetic drug that will produce safe anesthesia, analgesia (absence of pain), and in some surgeries, effective skeletal muscle relaxation. General anesthesia is most commonly achieved when the anesthetic vapors are inhaled or administered intravenously (IV). Volatile liquid anesthetics produce anesthesia when their vapors are inhaled. Volatile liquids are liquids that evaporate on exposure to air. Examples of volatile liquids include halothane, desflurane, and enflurane. Gas anesthetics are combined with oxygen and administered by inhalation. Examples of gas anesthetics are nitrous oxide and cyclopropane. 

Enflurane (Ethrane) is a volatile liquid anesthetic that is delivered by inhalation. Induction and recovery from anesthesia are rapid. Muscle relaxation for abdominal surgery is adequate, but greater relaxation may be necessary and may require the use of a skeletal muscle relaxant. Enflurane may produce mild stimulation of respiratory and bronchial secretions when used alone Hypotension may occur when anesthesia deepens. 

Halothane (Fluothane) is a volatile liquid given by inhalation for induction and maintenance of anesthesia Induction and recovery from anesthesia are rapid, and the depth of anesthesia can be rapidly altered. Halothane does not irritate the respiratory tract, and an increase in tracheobronchial secretions usually does not occur. Halothane produces moderate muscle relaxation, but skeletal muscle relaxants may be used in certain types of surgeries. This anesthetic may be given with a mixture of nitrous oxide and oxygen. 

Desflurane (Suprane), a volatile liquid, is used for induction and maintenance of anesthesia A special vaporizer is used to deliver this anesthetic because delivery by mask results in irritation of the respiratory tract. 

Toluene, volatile nitrites, and anesthetics, like other substances of abuse such as cocaine, nicotine, and heroin, are characterized by rapid absorption, rapid entry into the brain, high bioavailability, a short half-life, and a rapid rate of metabolism and clearance (Gerasimov et al. 2002 Pontieri et al. 1996, 1998). Because these pharmacokinetic parameters are associated with the ability of addictive substances to induce positive reinforcing effects, it appears that the pharmacokinetic features of inhalants contribute to their high abuse liability among susceptible individuals. 

Similar to alcohol (Lovinger and White 1991) and volatile anesthetics (Machu and Harris 1994), trichoroethane, trichloroethylene, and toluene enhance 5-HT3 receptor function. All three inhalants significantly and reversibly potentiated, in a dose-dependent manner, 5-HT-activated currents, mediated by mouse 5-HT3 receptors expressed in Xenopus oocytes. Another feature common to these drugs is that the acute use of inhalants, as well as alcohol and volatile anesthetics, can produce nausea and vomiting (Meredith et al. 1989). It is believed that 5-HT3 receptors located in the area postrema mediate this action of alcohol and the volatile anesthetics (Aapro 1991). 

Beckstead MJ, Phelan R, Mihic SJ Antagonism of inhalant and volatile anesthetic enhancement of glycine receptor function. J Biol Chem 276 24959-24964,2001 Beckstead MJ, Phelan R, Trudell JR, et al Anesthetic and ethanol effects on spontaneously opening glycine receptor channels. J Neurochem 82 1343-1351,... 

Yanagita T, Takahashi S, Ishida K, et al Voluntary inhalation of volatile anesthetics and organic solvents by monkeys. Jpn J Clin Pharmacol 1 13—16, 1970 Yavich L, Zvartau E A comparison of the effects of individual organic solvents and their mixture on brain stimulation reward. Pharmacol Biochem Behav 48 661— 664, 1994... 

STEROID (alphaxalone, allopregnanolone) VOLATILE ANESTHETIC (halothane)... 

The GABA-gated chloride ion channel is modulated by several classes of drugs that bind to allosteric sites on the receptor complex the benzodiazepines, barbiturates and related intravenous general anesthetics such as etomidate and propofol, as well as anesthetic steroids and endogenous neurosteroids. It appears that some types of GABAa receptor are directly enhanced by ethanol and volatile general anesthetics (Fig. 16-2) [7,8,20]. 

---