Pharmacology - General and local anesthetics Flashcards
5 primary effects of general anesthetics
Unconsciousness Amnesia Analgesia Inhib of autonomic reflexes Skeletal muscle relaxation
CNS depression stage 1
Analgesia–>analgesia and amnesia
CNS depression stage 2
Delirious
Retching and vomiting if stimulated
Irregular–>regular breathing
CNS depression stage 3
Regular breathing–>apnea
Loss of response to pain
CNS depression stage 4
Deepest
Depression of vasomotor and respiratory centers
Need circulatory and respiratory support
Toxicity of inhaled anesthetics
Nausea/vomiting
Halothane–>hepatitis after previous first time exposure
Metab to fluoride ions–>renal toxicity
In combination with succinylcholine–>malignant hyperthermia
Thiopental
Barbiturate
GABAa agonist
Sedation to general anesthesia (no analgesia)
Resp depression
Methohexital
Barbiturate
GABAa agonist
Sedation to general anesthesia (no analgesia)
Preferred over thiopental for short procedures due to quick elimination
Diazepam
Benzodiazepine
GABAa agonist
Used perioperative for anxiolytic and anterograde amnesia properties (terminated by flumazenil)
Anticonvulsant properties
Lorazepam
Benzodiazepine
GABAa agonist
Used perioperative for anxiolytic and anterograde amnesia properties (terminated by flumazenil)
Anticonvulsant properties
Midazolam
Benzodiazepine
GABAa agonist
Used perioperative for anxiolytic and anterograde amnesia properties (terminated by flumazenil)
Anticonvulsant properties
Water soluble–>good for parenteral administration
IV before operating due to rapid onset, shorter elimination, steeper dose-response curve
IV Anesthetics
Barbiturates Benzodiazepines Opioid analgesics Propofol Fospropofol Etomidate Ketamine Dexmedetomidine
Fentanyl, sufentanil, remifentanil, morphine
Opioid analgesics
Opioid recep agonists
Use in combination with benzodiazepines
Due to adverse effects, used as premedication and adjunct to IV and inhaled
Propofol
GABAa agonist
Most common parental anesthetic
Continuous infusions and anesthesia maintenance
Poor water solubility
Formulated with soybean, glycerol, and lecithin–>allergic rxn possible
Rapid onset/recovery/metabolization in liver
No analgesic properties
Decr cerebral flow and metab rate
Decr ICP and IOP
Burst suppression in EEG–>neuroprotective
Decr bp
Inhib baroreflex response–>hypotensive
Depress resp, apnea after induction dose
Reduce upper airway reflex
Painful injection
Fospropofol
Prodrug of propofol
Metab by alkaline phosphatase–>propofol, phosphate, formaldehyde
Similar to propofol, but onset and recovery prolonged
Less pain
Adverse effects include paresthesias and pruritis
Etomidate
GABAa agonist Hypnotic, not analgesic Minimal CV and resp depression Rapid LOC Less rapid recovery Metab by liver and in plasma Decr cerebral flow and ICP Minimal change in HR and CO Less pronouced resp depression Inhib 11b-hydroxylase-->adrenocortical suppression
Ketamine
NMDA antagonist Dissociative anesthetic state, catatonia, amnesia, analgesia With or without LOC Incr lacrimation and salivation Incr cerebral flow and CMRO2 Unpleasant emergence May be euphoric Incr bp, HR, CO Direct myocardial depressant, but masked by symp stim Minimal resp depression
Dexmedetomidine
Alpha2 agonist Hypnosis and analgesic effects Sedative resembles physiologic sleep Decr HR, systemic vasc resist, bp Short term sedation or adjunct to general anesthesia
Benzocaine
Local anesthetic
Poor solubility in water
Anesthetic lubricant
Topically for dermatologic conditions, hemorrhoids, premature ejaculation
Bupivacaine
Local anesthetic
Long duration of action
More sensory block than motor
Cocaine
Local anesthetic Blockage of nerve impulses Inhib NET-->incr NE-->vasoconstriction Dopamine reuptake inhib-->euphoria Topical anesthetic for upper resp
Dibucaine
Local anesthetic
Toxicity assoc with injections
Used as topical cream
Lidocaine
Local anesthetic
Amide that is an alternative choice for indiv sensitive to esters
Faster, more intense, longer lasting, more extensive than procaine
Antiarrhythmic agent
Procaine
Local anesthetic
Lower potency, slower onset, shorter duration than newer agents
Metab to para-aminobenzoic acid–>inhib sulfonamide abx
Ester-type vs amide-type local anesthetics
Ester-type has one “i”
Amide-type has at least two “i”s
