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Sedation in the GI Suite
Curt Mardis, MDStaff Anesthesiologist
St Mary’s Medical CenterEvansville, Indiana
Objectives
• Review the pharmacodynamics of medications used for sedation– Mention common side effects
• Review the pharmacokinetics of these same medications
• Review the antidotes for medications• Review fundamentals of airway
management• Review rescue medications
Basic nomenclature
• Pharmacodynamics– What a drug does to the body– Study of the biochemical and physiological effects of
drugs on the body
• Pharmacokinetics– What the body does to a drug– Studying the fate of substances administered
externally to a living organism– Include pharmaceutical agents, hormones, nutrients,
and toxins
Midazolam (Versed)
• Benzodiazepine• Enhances effect of GABA on GABA A receptors• Used to treat acute seizures• Induce sedation and amnesia before medical
procedures
Midazolam (Versed)
• Potent anxiolytic and amnestic medication
• Anticonvulsant and sedative properties
• Most commonly used benzo for sedation, because of very fast recovery time
• Less commonly used for induction and maintenance of anesthesia
Midazolam drawbacks
• Tolerance
• Withdrawal syndrome
• Paradoxical effects can occur, especially at high doses– Children– Elderly
Midazolam and lethal injection
• Manufacturer of pentobarbital has disallowed its use for lethal injection
• Florida used midazolam to execute a prisoner in 2013
• Ohio used midazolam in 2014
Flumazenil
• GABA A receptor antagonist• Antidote to benzo overdose• Antidote to overdose of non-
benzodiazepine sleep enhancers– Zolpidem– Zaleplon– Zopiclone
• 200 mcg IV every 2 min, up to 3 mg/hour
• Strong agonist at mu-opioid receptors
• Potent synthetic opioid analgesic with rapid onset, short duration of action
• Commonly used in procedures for analgesia
• 50-100x more potent than morphine
Fentanyl
Fentanyl
• Side effects– Nausea– Constipation– Dry mouth
• Less nausea than morphine• Less histamine-induced itching than
morphine• Responsible for many fatal overdoses, due
to respiratory depression
Naloxone (Narcan)
• Opioid antagonist• Antidote to opioid overdose
– Fentanyl– Morphine– Heroin
• Naloxone can be administered IV, IM, SQ, or via nasal mucosa
• Start at 80 mcg, then 4 mcg/kg/hour gtt
Propofol (Diprivan)
• Potentiates GABA A receptor activity
• Acts as a sodium channel blocker
• Diprivan: diisopropyl IV anesthetic
• Anti-emetic
• Rapid onset and recovery
Propofol Adverse Effects
• Vasodilation
• Decreases SVR
• Hypotension
• Apnea
Propofol and lethal injection
• Missouri Supreme Court– Propofol for lethal injection is constitutional
• First execution was scheduled for October 2013, but halted
• European Union threatened to limit drug’s export to United States
Epinephrine
• Useful medication in emergency
• Non-specific agonism at adrenoreceptors
• Increases heart rate and blood pressure
• Increases coronary perfusion pressure
Atropine
• Competitive antagonist at muscarinic acetylcholine receptors
• Dilates pupils
• Increases heart rate
• Antidote to vagal responses