Anesthetic usage

An ideal inhalation anesthetic would exhibit physical, chemical, and pharmacological properties allowing safe usage in a variety of surgical interventions. 

Nitrous Oxide. Nitrous oxide, described by Priesdy in 1772, was first used to reHeve severe dental pain in the latter part of the 18th century. Sometime in the mid-1800s N2O was successfully used as an anesthetic, and its widespread usage coincided with the development of anesthesia machines. Nitrous oxide is a nonflammable, colorless, odorless, and tasteless gas that can exist as a Hquid under pressure at room temperature. It is normally stored in cylinders. However, it supports combustion. 

Medical Usage. Isopropyl alcohol is also used as an antiseptic and disinfectant for home, hospital, and industry (see Disinfectants and antiseptics). It is about twice as effective as ethyl alcohol in these appHcations (153,154). Rubbing alcohol, a popular 70 vol % isopropyl alcohol-in-water mixture, exemplifies the medicinal use of isopropyl alcohol. Other examples include 30 vol % isopropyl alcohol solutions for medicinal liniments, tinctures of green soap, scalp tonics, and tincture of mercurophen. It is contained in pharmaceuticals, eg, local anesthetics, tincture of iodine, and bathing solutions for surgical sutures and dressings. Over 200 uses of isopropyl alcohol have been tabulated (2). 

Ketamine has been approved for both human and animal use as an injectable anesthetic in medical settings since 1970. About 90% of the ketamine legally sold in the United States in 2001 was intended for veterinary use, and over the past several years medical usage of ketamine has remained fairly constant. Production of ketamine, however, has increased almost 40% over the last six years, indicating a great deal of the substance is being diverted for illegal use. 

Indirect sympathomimetics (B) in the narrow sense comprise amphetamine-like substances and cocaine. Cocaine blocks the norepinephrine transporter (NAT), besides acting as a local anesthetic. Amphetamine is taken up into varicosities via NAT, and from there into storage vesicles (via the vesicular monoamine transporter), where it displaces NE into the cytosol. In addition, amphetamine blocks MAO, allowing cytosolic NE concentration to rise unimpeded. This induces the plasmalemmal NAT to transport Luellmann, Color Atlas of Pharmacology All rights reserved. Usage subject to terms... 

Many barbituric acid derivatives have been formulated since the early 1920s. Only a few remain in regular clinical usage and only one, thiopental, is used with any regularity in equine anesthesia. Thiopental is classified as a thiobarbiturate because there is a sulfur atom on the second carbon of the barbituric acid ring. It is also classified as an ultrashort-acting barbiturate. The presence of the sulfur atom decreases the stability of the molecule and shortens the duration of anesthetic action (Branson Booth 1995). 

PCP is a controlled substance called phencyclidine that causes hallucinations. Usage can result in assaults, murders, and suicides. PCP was developed in the late 1950s as a dissociative anesthetic that leaves a patient awake but detached from surroundings and unresponsive to pain. Once the dmg s hallucinogenic effect was discovered, PCP was withdrawn from use in humans, but continued to be used in veterinary medicine. PCP picked up the street name hog because of its use with animals. 

The two stmcturally similar compounds, CHF2OCF2CHFCI (Enfiurane) and CHF2OCHCICF3 (Isoflurane), have found use as inhalational anesthetics. This usage, coupled with their potential effects on stratospheric ozone (due to the presence of Cl), has led to numerous studies of their atmospheric behavior. As summarized in table III-G-79 and figure III-G-12, rate coefficients for reaction of OH with both species... 

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