Focus on PHARMACOLOGY ESSENTIALS FOR HEALTH PROFESSIONALS CHAPTER Anesthetic Agents 19

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Multimedia Directory Slide 32Mechanism of Action of Lidocaine Animation

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Ideal Anesthetic Rapid and pleasant induction and withdrawal from anesthesia Skeletal muscle relaxation Analgesia High potency Wide therapeutic index Nonflammable Chemical inertness

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Stages of Anesthesia 1.Analgesia: pain abolished but consciousness retained 2.Excitement: unconsciousness but possible unpleasant shaking, violence, and fear

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Stages of Anesthesia 3.Surgical anesthesia: progressive muscle relaxation and unconsciousness 4.Medullary paralysis: respiratory failure and circulatory collapse

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Preoperative Medications Adjuncts to surgery; preanesthetics Used to reduce anxiety, sedate, produce amnesia, increase comfort, reduce gastric acidity and volume, increase gastric emptying, decrease nausea and vomiting, reduce incidence of aspiration

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 19-1 Preoperative Medications as Adjuncts to Surgery

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 19-1 (continued) Preoperative Medications as Adjuncts to Surgery

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 19-1 (continued) Preoperative Medications as Adjuncts to Surgery

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini General Anesthetics Affect whole body; produce unconsciousness by depressing CNS Skeletal muscle relaxation and diminished reflexes Used in combinations to smoothly and rapidly induce anesthesia and allow prompt recovery; ensure wide safety margin; and reduce side effects

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Choosing Appropriate Anesthesia The choice of anesthetic drug depends on many factors, including: –Patient’s general physical condition –Area being operated on –Anticipated length of procedure

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Adverse Drug Reactions Older adults are more likely to experience adverse drug reactions than younger adults because, in general, they take more medications.

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Types of General Anesthesia Inhalation anesthetics: volatile liquids or gases Intravenous anesthetics

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 19-2 General Anesthetics Used by Inhalation

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Dangers of Malignant Hyperthermia Malignant hyperthermia is a life- threatening, acute pharmacogenetic disorder that develops during anesthesia. Characterized by rapid increase in body temperature, unexplained tachycardia, unstable blood pressure, muscle rigidity, and cyanosis

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 19-3 General Anesthetics Commonly Given by Injection

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Figure 19-1A Mechanism of action of anesthetics: normal nerve conduction.

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Figure 19-1B Mechanism of action of anesthetics: anesthetic blocking sodium channels.

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Diabetes and Surgery The stress of surgery in diabetic patients may increase blood glucose levels. Insulin or hypoglycemic medications should be coordinated with the: –Patient –Surgeon –Anesthesiologist

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini General Anesthetics: Uses Lipophilic agents that cross blood–brain barrier to close sodium channels to prevent neural conduction Used in combination to produce balanced anesthesia

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini General Anesthetics: Adverse Effects Common: drowsiness, weakness, or fatigue for a few days postanesthesia; fuzzy thinking, blurred vision, incoordination Other: headache, shivering, muscle pain, nausea and vomiting, sore throat, nightmares

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini General Anesthesia: Contraindications Contraindicated in patients who: –Have received MAOIs in previous 14 days –Are intolerant to benzodiazepines

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini General Anesthesia: Contraindications Also contraindicated in patients who have: –Hypersensitivity –Myasthenia gravis –Acute glaucoma –Increased intracranial pressure

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini General Anesthesia: Contraindications Also contraindicated in patients who have: –Impaired cerebral circulation –Alcohol intoxication –Status asthmaticus –Porphyrias

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Local Anesthetics Used to provide regional or topical anesthesia without loss of consciousness Two groups: esters and amides

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 19-4 Local Anesthetics

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 19-4 (continued) Local Anesthetics

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Amide Anesthetics: Uses Inhibit sodium channels, which inhibits nerve impulse transmission Used to increase patient comfort and cooperation during procedures including incision and drainage, laceration repair, biopsy, wart treatment, vasectomy, neonatal circumcision, dental procedures, childbirth, diagnostic procedures

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Amide Anesthetics: Adverse Effects Toxic effects are dose related. Symptoms of toxicity: dizziness, nystagmus, restlessness, disorientation, psychosis, slurred speech, tremors, hypotension, bradycardia, cardiac arrest

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Amide Anesthetics: Contraindications Contraindicated in older adults, debilitated adults, and children; pregnancy, labor, lactation, sepsis, acidosis, heart or spinal block, severe hemorrhage, hypotension and shock, hypertension, and more Local anesthetics interact with many drugs.

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Amide Anesthetics: Patient Information Instruct patients to report –Dizziness –Disorientation –Slurred speech

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Mechanism of Action of Lidocaine Animation Click on the screenshot to view an animation showing the mechanism of action of lidocaine. Back to Directory

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Specific Anesthetic Applications Topical anesthesia Infiltration anesthesia Field block anesthesia Nerve block anesthesia Spinal anesthesia Epidural anesthesia

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Figure 19-2 Techniques for applying local anesthesia: topical (A), nerve block (B), infiltration (C), spinal (D), and epidural (E).

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Topical Anesthesia Application of nerve conduction blocking agent onto tissue layer Provides anesthesia of urethra, vagina, rectum, skin Affected tissue is limited to area in contact with topical anesthesia. Cryoanesthesia: application of freezing agent

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Local Infiltration Anesthesia Blocks nerves Produced by injection of anesthetic into an area Most common local anesthesia

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Field Block Anesthesia Affects a single nerve, deep plexus, or network of nerves Administered in series of injections to form a wall of anesthesia around an operative field

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Spinal Anesthesia Anesthetic agent is injected into subarachnoid space through a spinal needle Used for gynecological, obstetrical, orthopedic, and genitourinary surgery

Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Epidural Anesthesia Injection of local anesthetic into epidural space via a catheter; allows repeated infusions Anesthetic agent is slowly absorbed into cerebrospinal fluid. Used for labor and delivery