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Ch. 9 - Local Anesthetics

Terms in this set (24)

- vasoconstrictor
- antioxidant
- sodium hydroxide
- sodium chloride
- propylparaben
What 5 things make up the composition of local anesthetics?
- retard absorption
- reduce systemic toxicity
- prolong duration of action
- keep anesthetic in injected area
Vasoconstrictors are added to local for what purpose?
- sodium metabisulfite, sodium bisulfite, acetone sodium bisulfite
- retard oxidation of epinephrine; & prolong shelf life
Antioxidants are added to local for what purpose?
Alkalinizes the solution to pH b/w 6-7
Sodium hydroxide is added to local for what purpose?
Makes the injectable solution isotonic
Sodium chloride is added to local for what purpose?
- prevents bacterial growth
- not used in single dose cartridges
Propylparaben is added to local for what purpose?
A color-coding system, part of the labeling for all injectable locals that carried the ADA Seal of approval
In 2003, the American Dental Association (ADA) Council on Scientific Affairs implemented what?
The only class of anesthesia used parenterally
Amides
Occasionally used topically; currently none available in dental cartridges
Esters
True
T/F - Lidocaine w/ epinephrine is good for almost all dentistry?
- Xylocaine & Octocaine
- introduce in 1948
- amide derivative of xylidine
- the anesthesia standard against which other locals were compared
- 2% w/ vasoconstrictor = profound anesthesia of medium duration (most commonly used in dental)
- adverse rxn: hypotension, positional headache, shivering
- topical, infiltration, block, spinal, epidural, & caudal anesthesia
- used intravenously to tx arrhythmias
- dentistry: 2% w/ 1:100,000 epi = infiltration & block anesthesia
Lidocaine
- Carbocaine, Polocaine, Isocaine
- use plain to avoid vasoconstrictors
- amide derivative of xylidine, introduce 1960
- not effective topically; use for infiltration, block, spinal, epidural, & caudal anesthesia
- dentistry: 2% soln. w/ 1:20,000 levonordefrin as vasoconstrictor
- short procedures when vasoconstriction contraindicated
- CAUSTION: used w/o vasoconstrictor will call for higher concentration & systemic toxicity more likely
Mepivacaine
3% solution w/o vasoconstrictor
Mepivacaine "plain"
- Citanest & Citanest Forte
- a toluidine derivative
- less potent/toxic than lidocaine w/ slight longer duration of action
- satisfactory anesthesia w/ low concentrations of epinephrine or w/o epinephrine
- toxic @ 60%
- excessive doses cause cyanosis of lips/mucous membranes, respiratory & circulatory distress
- do NOT administer to pt w/ any condition which oxygenation is critical; drugs that affect hemoglobin may worsen adverse rxn
- methemoglobinemia is reversible w/ IV methylene blue
- duration of action longer than
Prilocaine
- Marcaine
- amide type local
- more potent/toxic than other amides
- major advantage: greatly prolonged duration of action, indicated for lengthy procedures (dental procedures longer than 1.5 hrs or postop pain)
- w/ epi: onset of action bit longer than lidocaine & duration 2x that of lidocaine
- do NOT use w/ pt prone to self-mutilation
- infiltration, block, & peridural anesthesia
Bupivacaine
- Septocaine
- derived from thiophene; greater lipid solubility & ability cross lipid barriers
- approved in US 2000 & Europe in 1970s
- extra ester linkage = causes it to be hydrolyzed by plasma esterase
- 5-10% metabolized by liver, other 90-95% metabolized in blood
- excreted by kidneys: 40-70% articainic acid, 2-5% unchanged, 4-15% articainic acid glucoronide
- pt can endured 2x as much lidocaine before max safe dose is reached
- rapid metabolism makes it a safer drug to reinject later during tx
most widely used local in almost every country
- relative lack of active metabolites lowers risk of toxicity (more desirable for reinjection)
Articaine
Paresthesia
Persistent anesthesia beyond expected duration of the local's action; tingling/burning beyond extended time
- Novocaine
- PABA
- antiarrhythmic agent
- not currently used in dentistry bc high rate of allergic rxn
Procaine
- Pontocaine
- PABA
- slow onset, long duration, 10x more potent/toxic that procaine
- dermatologic rxn: contact dermatitis, burn, sting, angioedema
- max absorbed dose = 20mg for topical
Tetracaine
- Dyclone
- topicla local neither ester or amide
- slight irriation/stinging
- onset 2-10 min, duration 30-60min
Dyclonine
- part of the ANS drugs = adrenergic agonists or sympathomimetics
- if localdoes not have this, it is removed from the injection site & distributed to systemic circulation
- "plain" (w/o) have shorter duration of action & more rapid buildup in system; toxic
Vasoconstrictors
It's protein-binding capacity
Duration of action of a local is primarily related to what?
The potency of a local anesthetic agent
Lipid solubility determines..
The potency & duration of action
The vasodilating property of a local can affect what?
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