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INTRODUCTION

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This chapter will be most useful after having a basic understanding of the material in Chapter 19, General Anesthetics and Therapeutic Gases and Chapter 20, Local Anesthetics in Goodman & Gilman’s The Pharmacological Basis of Therapeutics, 12th Edition. In addition to the material presented here, the chapters in the 12th Edition include:

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  • Details of the general principles of surgical anesthesia

  • A detailed discussion of the mechanisms of anesthesia

  • The chemical structures of parenteral, inhalational, and local anesthetics

  • A detailed discussion of therapeutic gases

  • Figure 20-3 which is a depiction of the local anesthetic receptor site

  • Table 20-1 Susceptibility to Block Types of Nerve Fibers

  • A detailed discussion of the mechanisms of action of local anesthetics

  • A detailed discussion of the various ways that local anesthetics are administered

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LEARNING OBJECTIVES

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  • Learn the mechanisms of action of parenteral, inhalational, and local anesthetics.

  • Understand the ways that anesthetics (parenteral, inhalational, and local) are used to facilitate surgical and other painful medical procedures.

  • Know the major pharmacological properties and toxicities of anesthetic drugs.

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DRUGS INCLUDED IN THIS CHAPTER

Articaine (SEPTOCAINE)

Benzocaine (large number of preparations for topical application)

Bupivicane (MARCAINE, SENSORCAINE, others)

Carbon dioxide

Chloroprocaine (NESACAINE)

Cocaine

Desflurane (SUPRANE)

Dexmedetomidine (PRECEDEX)

Dibucaine (NUPERCAINAL, others)

Dyclonine (over-the-counter products such as SUCRETS, ORAJEL and OVERNIGHT COLD SORE PATCH, and SKIN SHIELD LIQUID BANDAGE)

Enflurane (ETHRANE)

Etomidate (AMIDATE)

Fospropofol (LUSEDRA)

Halothane (FLUOTHANE)

Helium

Isoflurane (FORANE, others)

Ketamine (KETALAR)

Lidocaine (XYLOCAINE, others); transdermal patch (LIDODERM); oral patch (DENTIPATCH); combination with prilocaine in an occlusive dressing (EMLA); combination with tetracaine (PLIAGIS)

Mepivacaine (CARBAOCAINE, POLOCAINE, others)

Methohexital (BREVITAL)

Nitric oxide

Nitrous oxide

Oxygen

Pramoxine (various preparations including creams, lotions, sprays, gel, wipes, and foams available for topical application)

Prilocaine (CITANEST)

Procaine (NOVOCAINE)

Proparacaine (ALCAINE, OPHTHAINE, others)

Propofol (DIPRIVAN)

Ropivacaine (NAROPIN, others)

Sevoflurane (ULTRANE, others)

Tetracaine (PONTOCAINE)

Thiopental Sodium (PENTOTHAL, others)

Xenon

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MECHANISMS OF GENERAL ANESTHESIAa

  • Cellular mechanisms

    • Inhalational anesthetics can hyperpolarize neurons.

    • Inhalational and parenteral anesthetics have effects on synaptic transmission and lesser effects on action-potential generation or propagation.

  • Molecular mechanisms

    • Increase sensitivity of the GABAA receptor to GABA, thus enhancing inhibitory neurotransmission.

    • Ketamine, nitrous oxide, and xenon inhibit NMDA receptors, which are glutamate-gated cation channels.

    • Halogenated inhalational anesthetics, xenon, and nitrous oxide activate K+ channels known as two-pore domain channels located in pre-and postsynaptic sites.

aDetails can be found in Chapter 19 of Goodman and Gilman’s The Pharmacological Basis of Therapeutics, 12th Edition.

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Table Graphic Jump Location
MECHANISMS OF ACTION OF ANESTHETIC AGENTS

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