Barbiturates Flashcards
Protein bound
NaP 83% bound
Mechanism of action
Interact with GABA-A subunit receptor Directly activate Cl channel Increase duration of opening Increase efficacy of GABA Hyperpolarize post synaptic cell membranes Block AMPA
Lipid soluble
Highly- enters CNS Rapidly 30 secs
Awakening after single dose
Prompt
Metabolism
Hepatic (inactive)
Eliminated
Kidneys
Cardiovascular effects
decrease SBP, SVR
Increase HR
Pulmonary effects
Respiratory depression
Apnea
Return with slow respers
Decreases tidal volume
CNS effects
Decrease CBF, ICP, CMRO2
Renal effects
Modest decrease in blood flow and GFR
pH
Metabolic acidosis increase effect of barbs
Metabolic alkalosis decreases effect of barbs
Respiratory acidosis much less effect
Thiopental supplied
2.5% solution
Methohexital supplied
1% solution
Induction of anesthesia
3-5 mg/kg NaP
1-1.5 mg/kg methohexital
Rectal methohexital 20-30 mg/kg sedative
Caution if infiltrated
Tissue sloughing
NaP + SUX =
Concrete in The IV
Intro arterial injection causes
Severe vasoconstriction
Induce what system
P-450 system
Contraindicated
Acute intermittent porphyria
Awakens why?
Redistribution
NaP causes
Dose dependent Decrease SBP, SVR, CO due to myocardial depression and increased venous capacitance
Respiratory
Potent depressant
Poor analgesia may cause
Hyper analgesia
Contraindicated
Acute intermittent porphyria
Histamine
Can be released and cause vasodilation
SubQ & Intra-arterial
Avoid
Onset and offset
Rapid
