General Anesthetics, Local Anesthetics, Muscle Relaxants Flashcards
Four stages of Anesthesia
- Analgesia
- Disinhibition
- Surgical anesthesia
- Medullary depression
A state characterized by unconsciousness, analgesia, amnesia, skeletal muscle relaxation and loss of reflexes
General Anesthesia
Stage of anesthesia: patient is unconscious, no pain reflexes, regular respiration and maintained blood pressure
Surgical anesthesia
Stage of anesthesia: severe respiratory and cardiovascular depression that requires mechanical and pharmacologic support
Medullary depression
Stage of anesthesia: patient is delirious or excited, amnesia occurs, reflexes are enhanced and respiration is typically irregular. Retching and incontinence may occur
Disinhibition
Stage of anesthesia: decreased awareness of pain, sometimes with amnesia. Consciousness is impaired not loss
Analgesia
Best measure of potency of inhaled anesthetics
Minimum Alveolar Anesthetic Concentration (MAC)
Defined as the alveolar concentration required to eliminate the response to a standardized painful stimulus in 50% of patients
Minimum Alveolar Anesthetic Concentration (MAC)
Most inhaled anesthetics are bronchodilators except for ____ which causes Asthma
Desflurane
Effect of having increased blood gas partition coefficient on action and recovery
Increased BG coefficient = slower onset of action, slower recovery
Decreased BG coefficient = faster onset of action, faster recovery
Inhalational general anesthetic for minor surgery and dental procedures. May cause megaloblastic anemia on prolonged used
Nitrous oxide
Lowest potency and least cardiotoxicity among inhalational anesthetics
Nitrous oxide
Inhalational general anesthetic with pungent smell. May cause bronchospasm and peripheral vasodilation
Desflurane
Inhalational general anesthetic, sweet-smelling and may cause peripheral vasodilation and renal insufficiency
Sevoflurane - facilitate GABA-mediated inhibition, blocks brain NMDA and ACh-N receptors
Inhalational general anesthetic that may cause arrhythmias, peripheral vasodilation and coronary steal syndrome
Isoflurane
Inhalational general anesthetic that may cause arrhythmias, myocardial depression and postoperative hepatitis
Halothane - may interact with succinyl choline causing malignant hyperthermia
Inhalational general anesthetic with highest potency and lowest MAC
Methoxyflurane
Ultrashort acting barbiturate that can be used as intravenous general anesthetic. May cause acute intermittent porphyria with additive CNS depression with Ethanol
Thiopental - SIMD: Methohexital, Thiamylal
Short-acting benzodiazepine used for intravenous general anesthetic. May cause anterograde amnesia, postoperative respiratory depression
Midazolam
IV general anesthetics, used for dissociative anesthesia. May cause emergence delirium, hypertension and increased ICP
Ketamine
IV general anesthetic with no analgesic property, for patients with limited cardiac and respiratory reserve. Less side effects
Etomidate - modulates GABA rceptors containing B3 subunits
IV general anesthetic, non selective opioid analgesic. May cause respiratory depression in M receptor, chest wall rigidity and constipation.
Fentanyl
Antidote for Fentanyl toxicity
Naloxone
IV general anesthetic that causes bradycardia and hypotension. Called as Milk of Amnesia, with additive effect with sedative-hypnotic drugs. MAC values decreases in elderly patient
Propofol - potentiates GABA receptors, blocks Na channels
Results when sensory transmission from a local area of the body to the CNS is blocked. Can be administered locally by injection or topical application to the target area
Local anesthesia
Local anesthetic that has the shortest half-life of 1-2 mins
Procaine
Local anesthetic with the longest half life
Ropivacaine - half life of 4.2 hours
Condition that enhances local anesthetic activity
Hyperkalemia
Condition that antagonizes local anesthetic activity
Hypercalcemia
All local anesthetics are vasodilators except?
Cocaine
Ester Local anesthetic also for extravasation complications from venipuncture and inadvertent intraarterial injections. May cause antibody formation
Procaine - blockade of Na channels slows, then prevent axon potential propagation
Ester Local anesthetic also for topical anesthesia. Use cautiously when treating sunburns or large areas of skin
Benzocaine
Ester Local anesthetic, drug of abuse. May cause antibody formation, abuse liability, severe hypotension, cerebral hemorrhage, cardiac arrhythmia or MI
Cocaine - also has intrinsic sympathomimetic activity
Ester Local anesthetic for spinal anesthesia, epidural anesthesia. With highest allergic potential
Tetracaine
Amide Local anesthetic that has group 1B antiarrhythmic activity
Lidocaine
Toxic dose of lidocaine
5mg/kg
Amide Local anesthetic also for dental anesthesia. May cause methemoglobinemia
Prilocaine
Amide Local anesthetic for local, epidural and intrathecal anesthesia. May cause severe cardiovascular toxicity.With caution in pregnant women.
Bupivacine
Treatment for Bupivacaine induced cardiotoxicity
Intralipid (fat emulsion used in TPN)
Amide Local anesthetic for local and epidural anesthesia. May cause cardiotoxicity. Can be reversed with Intralipid. Had the longest half life
Ropivacaine
drugs used to produce muscle paralysis to facilitate surgery or assisted ventilation.
Neuromuscular blocking drugs
Drugs used to reduce abnormally elevated tone caused by neurologic or muscle end plate disease
Spasmolytic drugs
Two types of neuromuscular blockade
Depolarizing blockade
Non-depolarizing blockade
Blockade: neuromuscular paralysis that results from persistent depolarization of the end plate
Depolarizing blockade
Blockade: neuromuscular paralysis that results from pharmacologic antagonism at the acetylcholine receptor of the end plate.
Nondepolarizing or stabilizing blockade
Nondepolarizing neuromuscular blocker with the most rapid onset time
Rocuronium - onset time of 60-120s
Nondepolarizing neuromuscular blocker. May cause respiratory paralysis, histamine release and recurarization. Relatively contraindicated in MI
Tubocurarine
Nondepolarizing neuromuscular blocker, short acting, metabolized by pseudocholinesterase
Mivacurium
Nondepolarizing neuromuscular blocker, intermediate acting, it undergoes Hoffman elimination
Atracurium - SIMD: Cisatracurium
Nondepolarizing neuromuscular blocker, intermediate acting, undergoes elimination in the bile. Muscle relaxation is potentiated with inhaled anesthetics, aminoglycosides and quinidine
Vecuronium
Nondepolarizing neuromuscular blocker, intermediate acting. With ost rapid onset time
Rocuronium
Novel reversal agent for Rocuronium
Sugammadex
Treatment for malignant hyperthermia
Dantrolene and rapid cooling of the patient
Nondepolarizing neuromuscular blocker, long acting, with moderate block on cardiac muscarinic receptors. Used for lethal injection, euthanasia, strychnine poisoning
Pancuronium
Earliest sign of malignant hyperthermia?
Contraction of jaw muscles (trismus)
Side effects of all Nondepolarizing neuromuscular blocker can be reversed by what?
Neostigmine
Drugs used in lethal injection
Thiopental 5mg
Pancuronium 100 mg - resp. paralysis
Potassium chloride 100mg - stop the heart
Phases of Depolarizing blockade
Phase I: Depolarization
Phase Ii: Desensitization
Phase: membrane depolarizes with initial electric discharge, transient fasciculations followed by flaccid paralysis
Phase I: Depolarization
Earliest sign of malignant hyperthermia?
Trismus
Phase: membrane repolarizes but receptor is desensitized to the effects of acetylcholine
Phase II: Desensitization
Depolarizing neuromuscular blocker, that may cause muscle pain, hyperkalemia, in severe cases malignant hyperthermia. Metabolized by pseudocholinesterase
Succinylcholine