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99 Cards in this Set
- Front
- Back
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What is the primary benefit of local anesthesia? |
Pain sensations can be supressed without significant CNS depression |
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What is the other advantages of local anesthesia |
Allows for the majority of dental procedures to be performed under local anesthesia without exposing patients to the risk of general anesthesia |
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What are two primary routes of delivary |
Topical Submucosal injection |
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An ideal ocal anesthetic would have the following specific properties dealing with biocompatibility (5) |
Non irritable Non toxic Non allergenic Biotransformable Completely reversible |
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An ideal local anesthetic would have the following specific properties of safety and Efficacy? (6) |
Effective in tissues and mucosa membranes Short onsets and no residual effects Reasonable durations Adequate potency Sterilizable Patients remain conscious |
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What are the two drugs that are acceptable both for topical and injectable agents in dentistry? |
Lidocaine Prilocaine |
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Injectable local anesthetic drugs in denistry are classified as either |
Amides Esters |
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The distinction between amides and esters is based on what |
Chemical nature of their intermediate chains Amide chain contains a nitrogen atom Esters chain does not contain a nitrogen atom |
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What are the two different chemical components |
Aromatic (Lipophilic) end Secondary or tertiary amine (hydrophilic) End Facilitates effectiveness in tissues |
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What does the aromatic (Lipophilic) end do |
allows the drug to pass through biological membranes of nerves |
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What does the hydrophilic end do? (2) |
Allows the agent to disperse in extra and intracellular fluids Provide for major pathways of biotransformation |
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Describe Esters (3) |
High incidences of allergies Has the estrogen atom Better to use on a patient with a liver disease |
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Describe Amides (3) |
Very rare allergy Metabolized in the liver with liver enzymes People with liver disease will have a hard time |
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Describe Pharmacodynamics |
The actions of a drug on the body ( what the drug does to the body) Actions on the peripheral nerves, the CNS, CVS, and other tissues. This action interrupts the normal generation and conduction of nerve impulses |
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Describe Pharmocokinetics |
The manner in which the body manages a drug ( Body does with the drug) such as Absorption Distribution metabolism elimination |
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The mechanism for the effect of local anesthetic drugs on nerve membranes is best explained by the?
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Specific protein receptor theory |
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What does the specific protein receptor theory state |
Action of local anesthetics on nerve membranes explained by the binding of local anesthetic molecules to structural proteins known as specific protein receptor sites Temporarily transform nerve membranes to nonexcitable states |
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What is the membrane expansion theory |
A modification of the membranes structure narrows the diameter of ion channels which limits the membrane's permeobility to sodium ions |
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What is the ionic basis of local anesthesia (3) |
Base molecule is lipophilic and passes through membrane Then it combines with hydrogen ions to from hydrophilic cations Only cations bind to receptor sites in sodium ion channels to block nerve impulse generation and transmission. |
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When tissues are inflammed at sites of deposition of local anesthetic drugs what happens |
Lowers pH inhibits base molecule production of neutral base molecules Results in insuffienct numbers of base molecules (RN) penetrating nerve membrane Profound anesthesia becomes difficult to acheive or to sustain |
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Describe pKa and pH |
Normal range is 7.7-8.1 The higher the pKa the longer the onset of anesthesia. |
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Describe vasoactivity in pharmocodynamics |
Dental local anesthetic drugs are peripheral vasodilators Limits their duration and efficacy unless vasocontristors are added |
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Why should blood vessels not be dilated |
Increase chance of toxicity Anesthesia wont last as long |
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Describe CNS and CVS actions of Local anesthetic drugs |
Central Nervous system is particulary susceptible to the effects of these drugs in the circulation |
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The syptoms of CNS depression have been characterized as |
Biphasics Temporary signs of excitation followed by CNS depression ( respiratory arrest) (Tonic-clonic convulsions) (Coma) |
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It will impact the CNS before it will effect the CVS. What has to happen for it to effect the CVS? |
Requires higher concentrations Vasodilation occurs, leading to depression of the myocardium |
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Pharmocokinetics describe the absorption and distribution of drugs |
Once absorbed into the systemic circulation, drugs are distrupted throughout the body |
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Pharmacokinetics describe biotransformation of drugs |
Metabolism of local anesthetic drugs, reduces or eliminates their toxicity |
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In Amides the pathway of biotransformation in the liver is known as
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(Hepatic p450 isoenzymes system) |
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In Esters the pathway of biotransformation in the in the blood by |
Pseudocholinesterase |
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Describe what elimation of haf life means in pharmacokinetics |
The rate at which a drug is removed from the systemic ciruculation The time necessary to metabolize and exrete 50% of a drug |
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What is the Half life of Articaine Prilocaine Lidocaine Mepivicaine Bupivacaine |
45 minutes 1.6 hours 1.6 hours 1.9 hours 3.5 hours |
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DENTAL LOCAL ANESTETIC DRUGS |
................... |
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What are the three different types of Lidocaine? |
2% Lidocaine Plain (w/out vasoconstrictor) 2% Lidocaine with 1:100,000 epinephrine 2% Lidocaine with 1: 50,000 epinephrine |
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When should Lidocaine plain be used (3) |
High blood pressure Cardiac patients Preservatic sodium bisulfate if a patient has an allergy to it (Sensitivity to Paba) |
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What is the duration of 2% Lidocaine Plain |
Very short duration= 5 to 10 minutes pulpal 60-120 minutes soft tissue |
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what is 2% lidocaine with 1:100,000 Epinephrine duration |
Intermediate duration= 60 minutes pulpal 180-300 minutes soft tissue |
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What is 2% lidocaine with 1: 50,000 epinephrine |
Intermediate duration= 60 minutes pulpal 180-300 minutes soft tissue |
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Which is the most common lidocaine used |
2% lidocaine with 1: 100,000 epinephrine |
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Which lidocaine has more epinephrine 2% lidocaine with 1:100,000 epinephrine or 2% lidocaine with 1: 50,000 epinephrine |
2% lidocaine with 1:50,000 epinephrine |
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what is plain lidocaine usually used for |
Soft tissue anesthesia |
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What are the colors of the three different lidocaines |
Blue: Plain Red: 1: 100,000 Green: 1:50,000 |
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What is the maxium recommended dose of Lidocaine |
2.0mg/lb (4.4mg/kg) 300 mg absolute MRD per appointment 150lbs or close to 150lbs: give 300mg |
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What is the metabolism of lidocaine |
Hepatic enzymes also known as oxidase and amidases |
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what is the excretion of lidocaine (the amount not used by the body) |
Less than 10% of lidocaine is excreted unchanged by the kidneys |
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What is the vasoactivity of lidocaine |
Potent vasodilator with a very short duration when administered without a vasocontristor |
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What is the onset of action (pKa) for lidocaine |
Approx. 2 to 3 minutes |
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Is lidocaine effective as a topical anesthetic |
YES Concentrations range from 2% - 10% Available in various ointment, viscous solutions, and mixtures |
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Safety during lactation |
Lidocaine enters breast milk in small amounts Caution is recommendd |
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What are the different types of Mepivicaine (2) |
3% Mepivacaine plain 2% Mepivacaine with 1:20,000 levonordefrin |
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What is the duration of 3% mepivacaine plain |
Short duration = 20 to 40 minutes pulpal 120-180 minutes soft tissue |
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What is the duration for 2% mepivacaine with 1:20,000 Levonordefrin |
Intermediate duration = 60 minutes pulpal 180 to 300 minutes soft tissue |
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What is the difference between levonordefrin and epinphrine |
Levonordefrin does the same thing as epiphrine just not as STRONG |
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What are the colors for the two different types of mepivicaine |
Gold Dark Rusty orange |
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What is the recommended dose of mepivicaine |
2.0 mg/lb (4.4mg/kg) 300 mg absolute MRD per appointment |
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Describe metabolism with Mepivicaine |
Metabolized in the liver Pathways are different compared with lidocaine Amidace activity is insignificant unlike Lidocaine |
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Describe Excretion of mepivicaine |
Variable with anywhere from virtually none to up to 16% exreted unchanged |
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What is the onset action of Mepivicaine |
Approximately 1.5 to 2 minutes |
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Are there any topicals for mepivicaine |
NO topical solution |
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Safety during lactation |
It is not known whether the drug is exreted in human milk Caution is recommended |
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what are the different types of Prilocaine |
4% prilocaine Plain 4% Prilocaine with 1:200,000 epinephrine |
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What is the duration of 4% prilocaine plain |
Short duration (Infilitration)= 10 to 15 minutes Pulpal 90 to 120 soft tissue Intermediate duration (block) = 40 to 60 minutes pulpal 180 to 480 soft tissue |
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What are the different colors for prilocaine |
4% prilocaine plain = Black 4% Prilocaine 1: 200,000 epinephrine = Yellow |
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What is the maxium recommeded dose for Prilocaine |
2.7 mg/lb (6.0 mg/kg) 400 mg absolute MRD per appointment |
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What should be cautioned when using Prilocaine |
Prilocaine's metabolite (o-toluidine), some individuals are at increased risk of developing a potentially life threatening anemia known as (METHEMOGLOBINEMIA) |
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Describe metabolism of Prilocaine (3) |
Simpler hepatic metabolism compared with lidocaine and mepivacaine (LIVER) Most of the drug is cleared before it reaches the liver The lungs and kidneys are alternate sites of break down when the liver is not used |
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Describe Excretion of Prilocaine |
Only small percentages of prilocaine and its metabolites are found in the urine |
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What is the onset action of Prilocaine
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Approx. 2 to 4 minutes |
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Can prilocaine be used as a topical preparation |
Only in combination with other drugs Typically 2.5% lidocaine with 2.5% Prilocaine (Oraqix and EMLA) |
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What are the different types of Articane |
4% Articane with 1:100,000 Epinephrine 4% Articane with 1:200,000 epinephrine |
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What is the duration time for 4% articaine with 1:100,000 epinephrine |
Intermediate duration = 60- 75 minutes pulpal 180 to 360 minutes soft tissue |
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What is the duration of 4% Articane with 1:200,000 epinephrine |
Intermediate duration |
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45-60 minutes pulpal 120-300 minutes soft tissue |
What are the different colorers of Articaine |
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What are the colors of the two epinephrines 4% Articane with 1:100,000 epinephrine 4% Articane with 1:200,000 epinephrine |
Yellowish gold Gray |
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What is the maxium recommended dose of Articaine |
3.2mg/lb (7mg/Kg) 500 mg Absolute MRD per appointment |
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What should be cautioned when using Articaine |
In addition to potentil CNS and CVS toxicity, articaine may induce methemoglobinemia when used in higer than therapuetic doeses |
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What are other special considerations that should be taken with Articaine |
Associated with higher than typical incidence of nerve damage/ paresthesia Reduce volume administered adhere to slow injection rates Avoid IA/L nerve blocks |
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Describe Metabolism with Articaine |
Unique 5-10% is metabolized via herpatic p450 enzymes The majority of Articaines metabolism is by rapid plasma cholinesterase (blood) to Articaine acid, prior to reachng the liver |
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What is ther excretion of Articaine |
Very little articaine, about 2% is excreted unchanged |
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What is the onset of action for Articaine |
Infilitration= approx, 1 to 2 minutes Nerve Blocks- approx 2 to 3 minutes |
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Is Articaine a good one to use for liver compromised patients |
YES |
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Is articaine used for a topical preparation |
NO |
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What are the different types of Bupivaine |
0.5% Bupivacaine with 1:200,000 epinephrine |
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What is the duration of 0.5% Bupivacaine with 1:200,000 Epinephrine |
Long duration = up to 12 hours pulpal and soft tissue |
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What is Bupivicaine usually used for |
Extended postoperative pain control (up to 12 hours of relief) In situtations where profund and durable anesthesia have proven to be difficult to acheive with all th eother available drugs Extended procedures greater than 60 to 90 minutes |
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What are certain procedures that usually use Bupivicaine
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Wisdom teeth extractions Root canal When no other anesthetic will work |
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What is the color of Bupivicaine |
Dark blue |
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What is the maximum recommended dose of Bupivicaine |
0.6 mg/lb (1.3mg/kg) Absolute MRD per apointment is 90mg |
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Describe the metabolism of Bupivicaine
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Complex the liver provides the major amidase pathways of metabolism Biotransformation is much slower compared with the other local anesthetic drug |
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Describe the Excretion of Bupivicaine
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Very little up to 16% is exreted in the urine unchanged |
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What is the onset of action for bupivicaine |
Approx. 6 to 10 minutes |
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Can Bupivicaine be used as a topical application |
NO |
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Describe Procaine |
No longer available in dental cartridges Represents the ester class of local anesthetics Used in a rare event that a patient is allergic to all amide anesthetic drugs |
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What is the proprietary name |
Novocaine |
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FDA drug categories in pregnancy is what |
A B C D X |
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What are the categories that we use only |
A or B |
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What does category A mean |
Adequate well controlled studies in pregnant women have no shown an increased risk of fetal abnormalities |
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What does category B mean |
Animal studies have revealed no evidence of harm to the fetus However there are no adequeate and well-controlled studies in pregnant women |
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List in order from most potent to least potent of anesthetic drugs (6)
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Bupivacaine Articaine Prilocaine Mepivacaine Lidocaine Procaine |
