question

cartridge contents

answer

local anesthetic drug, vasoconstritor, vaso preservative/sodium bisulfite, buffer/sodium hydroxide or sodium chloride, methylparraben/bacteriostatic agent and preservative (before 1984 only)

question

1.8 mL or 1.7 ml?

answer

most cartridges contain 1.8 mL but FDA requires it be labeled as 1.7 mL if manufacturer cannot guarantee due to slight machine variations

question

2 classifications of LAs

answer

esters metabolized in plasma by cholinesterase; and amides metabolized in liver, except articaine which is metabolized in blood --all for dentistry are amides because of possibility of hypersensitivity

question

5 generic classificaitons of amide LAs available for use in dentistry

answer

lidocaine mepivacaine prilocaine articaine bupivacaine

question

selection of LA determined on patient-by-patient basis with consideration of

answer

efficacy, safety, individual patient assessment, consultations and dental or dental hygiene care plan

question

DH must consider

answer

--duration of pain control based on length of procedure --need for post-treatment pain control --patient's health assessment and currents meds --allergy to sodium bisulfite, metabisulfite or local anesthetic --need for homeostasis

question

duration of action and operative pain control

answer

--lower pKa = more anions in base for better penetration, more rapid onset of action -- lipid solubility and protein-binding capacity related to duration of action -- lipid solubility determines potency

question

bupivacaine has highest perctnage of protein binding and is most lipid-soluble; so therefore has

answer

longest duration and is most potent --it also has hightest pKa, so slowest onset of action

question

mepivacaine and prilocaine have least vasodilating effects, allowing

answer

anesthetic to remain in area of deposition longer --therefore effective without a vasocinstrictor --good alternatives if vasoconstrictor contraindicated

question

duration of LA has 3 categories, influenced by presence or absence of a vasoconstrictor

answer

1. short acting: 30 min of pulpal anesthesia, no vasoconstrictor 2. intermediate acting: 60 min of poulpal anesthesia with a vasoconstrictor 3. long acting: 90+ minutes with a vasoconstrictor; only Bupivacaine

question

duration of anesthesia varies among patients depending on

answer

--individual response to anesthetic --accuracy of anesthetic administration --vascularity of tissue --variation of anatomic structure --injection technique

question

individual response, using Lidocaine 2%, 1:100,000 as an example

answer

normal responders, 70% hyper-responders, 15% hypo-responders, 15% --note in chart if hypo or hyper, or any modifications made to achieve appropriate duration

question

accuracy of anesthetic administration

answer

--most difficult when giving nerve block --least difficult when giving supraperiosteal

question

vascularity of tissue

answer

--onset of action and duration more predictable in healthy tissue --inflamed tissue has increased vascularity, so slower onset and decreased duration because of rapid absorption

question

variation of anatomic tissue

answer

difficult to predict, often decrease duration;

question

decreased duration and effectiveness in maxillae due to

answer

--density of bone --flaring of palatal roots --lower than normal zygomatic arch, esp in children

question

decreased duration and effectiveness in mandible due to

answer

--height of mandibular foramen --width of mandible --width and length of ramus --volume of musculature and adipose tissue --injection technique

question

posttreatment pain control if posttreatment discomfort expected

answer

--most procedures performed by DH fall within intermediate range --avoid longer-acting LA for children and special needs patients b/c of possibility of self-mutilation

question

patient health assessment and current meds

answer

evaluate at each appointment, then determine MRD

question

relative contraindication

answer

administration of offending drug may be used judiciously

question

absolute contraindicaiton

answer

offending drug should not be administered under any circumstances

question

maximum recommended dose/MRD

answer

maximum quantity of drug a patient can safely tolerate during an appointment based on physical status

question

local anesthetic, sodium bisulfite and metabisulfite allergy

answer

may include respiratory reactions in asthmatic patients --individuals allergic to sulfites should not be given LA with vasoconstrictor --if allergy to anesthetic, give one in different class

question

need for homeostasis

answer

--no difference in pain control b/c of epinephrine, but there is a difference in bleeding control --1:50,000 has most homeostasis --epinephrine better bleeding control than levonordefrin

question

lidocaine --a xylidine derivitive

answer

--first amide available for dentistry --most common --rarely used without a vasoconstrictor b/c of duration of pulpal anesthesia (60 min with, 5-10 min. without) --anticonvulsant properties; used to terminate seizures --only topical anesthetic available --avail in 3 formulations

question

mepivacaine --a xylidine derivitive

answer

similar to lidocaine in onset of action, duration, potency, toxicity and no reported allergic reactions --less vasodilation than lidocaine, so effective without a vasoconstrictor (3% formulation) --2% with levonordefrin used in US --but not same degree of homeostasis --not effective as topical

question

prilocaine --a toluidine derivative

answer

equal potency to lidocaine and mepivacaine --least toxic anesthetic available --good when need slightly longer duration of action --metabolized more easily by the liver --contraindicated for patients at risk of methemoglobinemia, or patients with oxygenation difficulties --topical uses combination with lidocaine

question

methemoglobinemia

answer

limiting factor for clinical use of prilocaine --presence of a higher than normal level of methemoglobin in blood that does not bind to oxygen --clinical cyanosis of the lips and mucous membranes can be observed

question

articaine, --thiophene derivative, which is an ester linkagae, so better lipid solubility --hydrolyzed by esterase and in liver

answer

--safer drug to readminister later during dental visit if more anesthesia needed --concern over increased incidence of paresthesia --good alternative for patients with increased risk of CV disease, or for those taking medications that enhance effect of epinephrine

question

bupivacaine

answer

--most potent and toxic --only one with long duration of action, but has slower onset --pulpal anesthesia for 1.5 to 3 hours, soft tissue 4-9 --good alternative when profound anesthesia hard to attain --not recommended for children or special needs

question

procaine/Novacain --an ester, still available for use in medicine --not used in dentistry

answer

--less potent and toxic than amides --used as an antiarrhythmic --greatest vasodilating properties, no pulpal anesthesia --was first injectable LA

question

buffering

answer

may improve patient comfort by eliminating the sting, may reduce tissue injury and may reduce anesthetic latency, may provide more effective anesthesia in area of infection

question

1. most important advantage of amide over ester local anesthetics

answer

less allergenicity

question

2. which local anesthetic is longest acting? --lidocaine, procaine, bupivacaine with epi, prilocaine with epi, articaine with epe

answer

bupivacaine with epinephrine

question

3. Which local anesthetic has the least vasodilatory effect when used without epinephrine? --mepivacaine, lidocaine, cocaine, procaine

answer

Mepivacaine --Mepivacaine has the least vasodilatory properties second only to prilocaine.

question

4. Which local anesthetic has the greatest vasodilatory effect when used without epinephrine? --mepvicaine, lidocaine, articaine, procaine

answer

procaine --Procaine has the greatest vasodilatory properties of all ester and amide local anesthetics.

question

5. One cartridge of anesthetic contains how much solution?

answer

1.8 mL

question

6. Factors in selection of local anesthetic for a patient include all of the following

answer

--length of time pain control is necessary --presence of any contraindication, absolute or relative --requirements for homeostasis --not influenced by vitamin intake

question

7. Which is false? --Esters of para-aminobenzoic acid are not commercially available. --Procaine is an ester. --Topical benzocaine is an amide. --Prilocaine is an amide.

answer

--Topical benzocaine is an amide. FALSE! --Benzocaine is an ester topical anesthetic. Lidocaine is the only topical anesthetic.

question

8. Which of the following LAs is metabolized in the plasma and liver?

answer

articaine

question

9. Which of of the following is an advantage of having a LA metabolized in the plasma and liver? --increased duration of action --shorter half-life of drug --decreased vasoactiviy of drug --easy excretion of metabolites

answer

shorter half-life --Articaine is metabolized predominately in the plasma, and has a half-life of 45 minutes compared to lidocaine's half-life of 90 minutes.

question

10. Which of the following LA is metabolized in the lungs and liver? --mepivacaine, bupivacaine, prilocaine or articaine

answer

prilocaine --It is metabolized easier by the liver than lidocaine and mepivacaine because much of the drug is already metabolized by alternate sites in the lungs and kidneys before it reaches the liver.

question

11. Methylparaben

answer

bacteriostatic agent that is no longer added to dental cartridges due to high incidence of allergic reactions

question

12. How is 3% mepivacaine formulated?

answer

3% plain --3% mepivacaine is only formulated without a vasoconstrictor.

question

13. Which of the following is a concern when selecting bupivacaine? --patient self-mutilation, decreased risk of toxicity, concentration of anesthetic, ease of biotransformation

answer

patient self-mutilation, because of longer duration

question

14. Best option for readministration of anesthetic to provide a lessened likelihood of blood concentration buildup? --lidocaine, mepivacaine, prilocaine, articaine or bupivacaine

answer

articaine --Because of articaine's rapid metabolism and its inactive metabolites, it may be a safer drug to re-administer later during a dental visit if more anesthetic is necessary.

question

15. The lower the pKa of a drug, the more cations are present, which decreases the onset of action.

answer

false; The lower the pKa, the more anions are present in base form for better penetration through the lipid rich nerve, which provides a more rapid onset of action.

question

16. Which is not a factor in the duration of a LA? --individual response, anatomic structure, patient health assessment, injection technique

answer

patient health assessment Duration of anesthesia varies among patients depending on individual response to anesthetic, accuracy of anesthetic administration, vascularity of tissue, variation of anatomic structure, and injection technique.

question

17. Which LA is used when a vasoconstrictor provides intermediate duration of action when administering a block injection? --lidocaine, mepivacaine, prilocaine or bupivacaine

answer

prilocaine --4% Prilocaine when administered as a block injection increases its duration from short to intermediate action providing pulpal anesthesia for approximately 40-60 minutes and soft tissue anesthesia for approximately 2 to 4 hours.

question

18. Which is the best reason for choosing a local anesthetic that provides a long duration? --need for postopertive pain control, medical status of patient, dense bone in area of administration, infection in the area

answer

need for postopertive pain control

question

19. When is lidocaine 1:50,000 epinephrine most effective?

answer

when homeostasis is needed

question

20. Where is procaine metabolized? --in liver, lungs, plasma or plasma and liver

answer

plasma --Procaine is an ester, and is metabolized via plasma cholinesterase to PABA, which is the major metabolic by-product responsible for allergic reactions.

WWA#3; Ch. 5: Local Anesthetic Agents – Flashcards

Unlock all answers in this set

Haven't found what you were looking for?

Search for samples, answers to your questions and flashcards