Anesthesia Drugs Flashcards
How does local anesthesia work
interrupts pain impulses in specific regions of the body, without LOC
what are the general side effects of anesthetics
CNS stimulation followed by drowsiness and sedation
HA
Paresthesias
Nausea
Cardiac depression, antiarrhythmic activity and wide QRS
blocks autonomic ganglia
C/I in myasthenia Gravis
What are the differences in the types of local anesthetics
Esters: short-acting, metabolized by plasma esterases, used topically or infiltrative, more likeky to cause hypersensitivity reactions
Amides: longer acting, metabolized by the liver
Rank the ester anesthetics from shortest actin to longest
- procaine
- tetracaine
- cocaine
- benzocaine
Rank the amide anesthetics from shortest actin to longest
lignocaine
Mepivicaine
Prilocaine
Bupivicaine
Ropivicaine
which general anesthetic is inhaled and what are the
side effects and contraindications
nitrous oxide
side effects: mild myocardial depression
increased pulmonary vessel resistance
c/i: pneumothorax and pulmonary HTN
What are the volatile liquid general anesthetics
Halothane
Enflurane
Isoflurane
Desflurane
Sevoflurane
the concentration of an inhaled anesthetic in a mixture of gasses is proportional to
its partial pressure
what determines the speed of achieving steady-state of an inhalational anesthetic
ventilation rate
cardiac output
blood-gas partition coefficient
what is the blood gas partition coefficient and what is its significance
ratio of anesthetic concentrations in the blood and alveolar space when partial pressure is equal
the higher the coefficient, the higher the solubility into blood and slower the action onset
the lower the coefficient, the faster the drug’s effect ceases
what is the minimal alveolar concentration
concentration at which 50% of subjects are immobile when exposed to noxious stimuli
what is the significance of the MAC
the lower the MAC, the more fat-soluble the drug is
how are inhalational anesthetics eliminated
lungs
steps of general anesthesia
- neruons in the spine are prevented from firing
- inhibition of inhibitory neurons causes paradoxical excitation
- suppression of the reticular activating system, LOC and inhibition of spinal reflexes, muscle relaxation
- can lead to cardiovascular collapse
MOA of general anesthetics
- drug binds to specific amino acid residues on transmembrane portions of GABAa receptor chloride channels
- increased chloride influx and potassium efflux from neurons causes hyperpolarization and reduces membrane excitability
- sodium and calcium influx is also reduced
side effects specific to isoflurane
pungent odor
side effects specific to desflurane
respiratory irritation:
coughing
salivation
bronchospasm
increased BP and HR
side effects specific to sevoflurane
bronchodilation and nephrotoxicity
which general anesthetic is metabolized by the liver
halothane
which general anesthetic has the most rapid onset of action and recovery
desflurane
Barbituates
MOA
side effects
contraindications
MOA: increases duration chloride channels are open, to hyperpolarized the neuron
side effects: hypotension, respiratory depression, laryngospasm, bronchospasm, myoclonus, painful injection, dependence, CYP450 inducer
contraindications: porphyria
Benzodiazepines
MOA
side effects
contraindications
MOA: increases frequency of chloride channels opening to hyperpolarize the postsynaptic neuron
side effects: blunted/ hangover effect, muscle weakness, amnesia, tolerance, dependence, paradoxical excitability, increased appetite, CNS depression
contraindications: myasthenia gravis, ataxia, narrow-angle glaucoma, pregnancy, respiratory depression, drug dependence
Propofol
MOA and Side Effects
MOA: acts at GABAa receptors and sodium channels of the reticular system
side effects: dose-dependent hypotension and respiratory depression, anaphylaxis with egg allergy, pain on injection, apnea, hypotonus
which anesthetic drug causes the least amount of CVS symptoms and what is its MOA/ side effects
Etomidate
MOA: acts at GABA receptors of the reticular formation
Side effects: causes transient acute adrenal insufficiency, postop N/V, painful injection, myoclonus
side effects of opioids
AMS
bilateral miosis
respiratory depression
seizure
decreased bowel sounds
decreased HR and BP
hypothermia
rhabdomyolysis
how do opioids work
inhibit adenyl cyclase to increase potassium conductance and decrease calcium conductance to cause inhibition of neurotransmitter release from the central termination of small-diameter primary fibers and inhibition of membrane depolarization of dorsal horn noicireceptive neurons
Ketamine
MOA
side effects
MOA: NMDA receptor antagonist
side effects: nystagmus, increased oxygen demand
increased pulmonary arterial pressure, increased ICP, hallucinations, nightmares, abnormal ECG, respiratory depression
who do you give ketamine to
polytrauma patients with risk of hypotension
treatment-resistant asthma
pediatrics
who is the best candidate for etomidate
patients with hemodynamic instability
