LA Flashcards
Formulation of Local Anesthetics
Water: vehicle HCl: improve solubility NaOH: adjust pH Editate disodium: adjust pH NaCl: adjust tonicity Epinephrine: vasoconstrictor Metabisulfite: antioxidant Methylparaben: antimicrobial
in LA Metabisulfite
antioxidant
prevents biodegradation of oxygen
in LA Methylparaben
antimicrobial
to make it less longer
bisulfite allergy
avoid vasoconstriction
Drug Interactions
LA with Epi
Monoamine oxidase inhibitors (MAOI): potentiation
Tricyclic antidepressants (TCAs): high blood pressure
Antipsychotics: serious heart problem
Digitalis glycosides: to much cardiac excitation
Non-selective β-Blockers: acute hypertensive episode
Cocaine: hypertensive crisis or cardiac dysrhythmia
Sedatives and opioids: respiratory depression
Diphenhydramine:
Saxitoxin
Tetrodotoxin
Alternative drugs to LA
diphenhydramine: antihistamines Mechanism of action unknown
Saxitoxin: paralytic shellfish toxins Block voltage-gated sodium channel
Tetrodotoxin: an extremely potent toxin found mainly in the liver and sex organs of some fish, such as puffer fish Block voltage-gated sodium channel
Phentolamine
used to reverse LA with vasoconstrictor
Adverse Effects – Acquired Methemoglobinemia
benzocaine
prolicaine
lidocaine
Fe2+——–>Fe3+
Levonordefrine
in LA
alpha - selective
used for pts with CVD
bispectral index
shows level of sedation
MAC
shows efficacy
train of four
level of paralysis
MOA for GA
block excitation: block glutamate receptors block nicotinic Ach receptora potentiate inhibition: activate GABA a and glycine channels _two-pore-domain K+ hyperpolarization and delayed transmission
NO
faster onset
less soluble
use as adjunct
analgesia and sedation rather then anesthesia
side effects: cardiac depressants and problem with breathing
Halogenated Gases
Halothane
Isoflurane
Desflurane
Sevoflurane
