Anesthesia Drugs Flashcards
What are the effects of inhaled anesthetics?
Myocardial depression
Respiratory depression
Nausea/emetics
Increased cerebral flow
What are the inhaled anesthetics?
Halothane Enflurane Isoflurane Sevoflurane Methoxyflurane Nitrous oxide
What is the toxicity of halothane?
Hepatotoxicity
What is the toxicity of methoxyflurane?
Nephrotoxicity
What is the toxicity of enflurane?
Proconvulsant
What is the toxicity of inhaled anesthetics in general except for nitrous oxide?
Malignant hyperthermia
What is the danger of nitrous oxide?
Expansion of trapped gas in the body
What is seen in the liver with halothane toxicity?
Massive hepatic necrosis
Sx: increased LFTs, liver tenderness, hepatomegaly
Light microscopy shows widespread centrilobular hepatic necrosis
What are the IV anesthetics?
Thiopental BZD Arylcyclohexylamines (ketamine) Opioids Propofol
What is the action of thiopental?
It is a barbiturate - so it facilitates GABA action by increasing the duration of chloride channel opening thus decreasing neuron firing
What is unique about thiopental?
It has high potency and high lipid solubility so it has rapid entry into the brain then it redistributes into the skeletal muscle and fat.
What is thiopental used for?
Induction of anesthesia
What is the MOA of midolazam?
It is a BZD so it facilitates GABA action - increases the frequency of chloride channel opening
What is midolazam used for?
Endoscopy
Adjunctively with gaseous anesthetics and narcotics
What are the side effects of midolozam?
Post op respiratory depression
Decreased BP
Amnesia
What is the MOA of the arylcyclohexylamines?
PCP analogs that act as dissociative anesthetics
They block NMDA receptors –> increase CV and cerebral blood flow
What are the side effects of arylcyclohexylamines?
Disorientation
Hallucination
Bad dreams
What are the opioids used in anesthesia?
Morphine
Fentanyl
What is propofol used for?
Sedation in ICU
Rapid anesthesia induction
Short procedures
What is the MOA of propofol?
Potentiates GABA
What is the advantage to propofol?
Less nausea than thiopental
What are local anesthetics?
Esters = -caines = procainamide, cocaine, tetracaine Amides = 2 I's in their names = lidocaine, mepivacaine, bupivacaine
What is the MOA of local anesthetics?
Block sodium channels by binding to specific receptors on inner portion of channel
They preferentially bind to inactivated sodium channels, so most effective in rapidly firing neurons.
Note: tertiary amines penetrate the bb barrier as uncharged form then bind ion channels in charged form
Why would you give vasoconstrictors with a local anesthetic?
To enhance the local action and increase anesthesia of the area by decreasing the systemic concentration
Why must more anesthetic be given when dealing with infected tissue?
Alkaline nature of amine anesthetics can’t penetrate because the acidic environment of the infection
What is the order of nerve blockade?
Small myelinated> small unmyelinated > large myelinated > large unmyelinated
What is the order of sensory loss?
Pain > temperature > touch > pressure
What are local anesthetics used for?
Minor surgery
Spinal anesthesia
What is the toxicity of local anesthetics?
CNS excitation Severe CV toxicity (bupivacaine) HTN Hypotension Arrhythmias (cocaine)
What are the drugs used for muscle paralysis during surgery.
NMJ blocking drugs : succinylcholine, tubocurarine, -curiums, -curoniums
What is succinylcholine?
A de polarizing Ach receptor agonist
What is the action of succinylcholine?
Produces sustained depolarization and prevents muscle contraction
What are the complications of using succinylcholine?
Hyperkalemia, hypercalcemia, malignant hyperthermia
What is phase I of reversal of succinylcholine blockade?
Prolonged depolarization
No antidote - prolonged by cholinesterase inhibitors
What is phase II of succinylcholine reversal blockade?
Repolarized but blocked - Ach receptors are available but desensitized - use cholinesterase inhibitors (stigmines)
What are the nondepolarizing NMJ blockers?
-curiums, tubocurarine, -curoniums
What is the MOA of nondepolarizing NMJ blockers?
Compete with Ach for receptors
How do you reverse blockade with nondepolarizing NMJ drugs?
Cholinesterase inhibitors
What is the MOA of dantrolene?
Prevents release of calcium from sarcoplasmic reticulum in skeletal muscle
What is dantrolene used for?
To tx malignant hyperthermia
Neuroleptic malignant syndrome
