Local Anesthetic Therapeutics Flashcards
Desirable properties of local anesthetics
Non-irritating Non-allergenic Minimal systemic toxicity Rapid onset Adequate duration Completely reversible effects Selective to nocioception (pain sensation) Effective as a topical agent
What effects does cocaine have on the body?
CNS stim- feeling of euphoria, well-being
Convulsions at high dosages
Cardiovascular stim- ^ BP, ^ HR, arrhythmias
Hyperexia- elevated temps
Used as local in upper respiratory procedures and as a topical for laceration repair
Characteristics of Procain “Novocain”
Ester anesthetic
Highly allergenic
Poor efficacy, profundity (depth), and duration
Which local anesthetic is used most for dental surgery?
Lidocaine
Characteristics of lidocain “Xylocain” “Lignospan”. What are the types available?
GOLD STANDARD
Excellent onset and profundity with vasoconstrictor
On its own considered a vasodilator which is why a vasoconstrictor is required
2% lidocaine HCl, 1:100,000
2% lidocaine HCl, 1:50,000
Characteristics of Prilocaine “Citanest”. Types available
Similar to lidocaine with epi
Metabolic product, toludine, may be responsible for the side effect of methemoglobinemia
4% prilocaine HCl, plain
4% prilocaine HCl, 1:200,000 epi
What is methemoglobinemia, what causes it, treatment?
Increase amts of hemoglobin with oxidized iron
Blood turns from red tochocolate brown
Induced by: prilocaine, benzocaine, nitrates and sulfonamides
Treated with infusion of methylene blue dye
What is the common name for the topical combination of prilocaine and lidocaine?
Oraqix
Characteristics if mepivicain “Carbocaine” “Polocaine”. Two formulations?
Shorter duration of pulpal anesthesia than lidocaine with epi
Minimal vasodilating properties
3% mepivicaine, plain
2% mepivicaine, 1:20,000
Characteristics of articaine “Septocaine” “Ultracaine”. Types available?
Similar anesthetic characteristics to lidocaine w/ epi
More effective than lidocaine for mandibular INFILTRATION
4% articaine, 1:100,000 epi
4% articaine, 1:200,000 epi
What allows us to administer repeated injections of articaine during lobg appointments?
Rapid elimination from systemic circulation from metabolism in plasma
Which injection do we NOT use articaine for? Why?
Mandibular blocks
Increased risk of paresthesia
Characteristics of bupivicaine “Marcaine” “Vivicaine”. Types available?
Long onset time due to elevated pKa
Prolonged soft tissue anesthesia- used for pot-op pain
Duration is due to protein bonding
0.5% bupivacaine, 1:200,000 epi
What will cause faster onset of anesthesia?
pKa that is closer to physiologic pH
What can determine, in large part, the toxic potential of the agent?
Pharmacokinetic consideration
Balance btw uptake of LA into the systemic circulation and its removal through redistribution, metabolism and excretion
A-absorption, D-distribution, M-metabolism, E-excretion
What is the driving force for distribution of the anesthetic agent? WHat is the greatest barrier to this?
Diffusion
The perineurium (nerve sheath) is the greatest barrier, free nerve endings affected within seconds
What does systemic absorption depend on?
Dose
Pharmacologic profile of agent
Presence of vasoconstrictor
Site of administration
Which anesthetics have potent vasodilating properties and require vasoconstrictors?
Lidocaine and procaine
Fast uptake requires vasoconstrictor to slow it down
Which anesthetics have minimal vasodilating properties?
Mepivicaine and Prilocaine
Require less vasoconstrictor to retard uptake
Which anesthetic is highly lipid soluble and therefore takes longer to take effect?
Bupivicaine- binds with injected tissues
Where does metabolism of esters occur?
In the blood stream by plasma cholinesterases
Where does metabolism of amide anesthetics occur?
In the liver
Which anesthetic has characteristics of both amides and esters and is mostly metabolized in the bloodstream?
Articaine
What are the most common systemic affects by local anesthetics?
Cardiovascular and CNS
But any organ dependent on nervous or muscular activity may be affected
