Lecture 4 Flashcards
what are the amide local anesthetics?
- lidocaine (xylocaine)
- prilocaine (citanest)
- articaine (septocaine)
- mepivacaine (carbocaine)
- bupivacaine (marcaine)
- etidocaine (duranest)
what are the ester local anesthetics?
- procaine (novacaine)
- propoxycaine (ravocaine)
- benzocaine (monocaine) - topical as well
- tetracaine (pontocaine)
___ can be used if a patient has an allergy to amides and/or esters
difanhydramine (aka benadryl)
what are the local anesthetics used in the dental office?
- articaine (septocaine)
- bupivacaine (marcaine)
- lidocaine (xylocaine or lido)
- mepivacaine (carbocaine, polocaine)
- prilocaine (citanest or citanest plain)
the duration of action of LAs depend on what 5 things?
- individual response
- accuracy of deposition
- tissue chemistry/biology
- anatomical variations
- type of injection
what are normoresponders, hyporesponders, and hyperresponders?
- normoresponders = 70% of people; those who respond “normally” to LAs
- hyporesponders = people who won’t stay anesthetsized very long (these are the hardest people to handle in the dental office); blood levels may exhibit overdose levels even if you don’t see the response clinically because it takes a lot more local anesthetic to get any response at all from hyporesponders as opposed to normoresponder; these patients are at higher risk for toxicity because there is a tendency to give them more LA to generate an affect, but that might mean the maximum dose is exceeded.
- hyperresponders = people who will stay anesthetized for longer periods of time; we may not even approach the maximum dose before we start to see clinical symptoms based on the nature of how those patients respond to LA.
with respect to tissue chemistry/biology, describe how the duration of action of an LA can be affected
- infection of abscess can limit the effectiveness of the LA
- vascularity of a site can do the same thing because if you inject into a hypervascular site, the depth and duration of action will be decreased because the LA will be more likely to leave that injection site
anatomically speaking, how can the duration of action of an LA be affected?
difficult for an injection to be consistent and reliable every time because the size and anatomy of the jaw will be different from patient to patient. the IA block is the most difficult injection to get reliability and consistency
maximum doses are measured in ___ or ___
mg/kg or mg/lb
who are vulnerable patients with respect to LA administration?
- smaller, lighter weight child and adult (smaller blood volume)
- debilitated, elderly patient - their bodies are less efficient at processing the drugs
the total volume in a cartridge is ___
1.8ml
what is the maximum recommended dose for lidocaine?
7.0mg/kg or 3.2mg/lb
how do you calculate the amout of LA in a carpule?
ex 2% lidocaine solution:
contains 20mg/ml lidocaine
20mg/ml x 1.8ml = 36mg lidocaine
a 22 yo healthy patient weighs 50kg. what is the maximum dose of lidocaine that can be administered (MRD = 7.0mg/kg)? how many carpules (there are 36mg in each carpule)?
MRD: 50kg x 7mg/kg = 350mg
of carpules: 350/36 = 9.7 carpules
what is the MRD for articaine?
7.0mg/kg or 3.2mg/lb
a 40yo healthy male weighs 90kg. what is the maximum dose of articaine that can be administered (MRD = 7.0mg/kg)? how many carpules (72mg per carpule)?
MRD: 90kg x 7.0mg/kg = 630mg
of carpules: 630mg/72mg = 8 carpules
how do you calculate mg/ml of 2% anesthetic? what about 3% anesthetic?
how do you calculate a 2% and 5% anesthetic if the cartridge volume is 1.8ml?
- 2% anesthetic = 2g/100ml = 2000mg/100ml = 20mg/ml
- 3% anesthetic = 3g/100ml = 3000mg/100ml = 30mg/ml
- 2% = 20mg/ml x 1.8ml = 36mg of anesthetic per cartridge
- 3% = 30mg/ml x 1.8ml = 54mg of anesthetic per cartridge
what is the alternative name, classificaiton, metabolism, excretion, duration, and onset of action of 2% procaine HCL, plain?
- aka: novacaine
- classificaiton: ester
- metabolism: plasma hydrolysis
- excretion: renal (90% PABA)
- duration: intermediate
- pulpal - negligible
- soft tissue - approx. 15-30 minutes
- onset of action: 6-10 minutes
what LA was historically the only LA used; because of intense vasodilatory effects, was short in duration, and is no longer used in the US?
2% procaine HCl, plain
aka novacaine
what is the alternative name, classification, metabolism, excretion, duration, onset of action, formulation w/epi, MRD, pregnancy risk, and precautions of 2% lidocaine, 1:100,000 epi?
- aka xylocaine
- classification: amide
- metabolism: hepatic
- excretion: renal (majority excreted as metabolites)
- duration: intermediate
- pulpal: approx 60 min
- soft tissues: approx 3-5 hours
- onset of action: 3-5 minutes
- formulation w/epi: 1:50,000 (green) and 1:100,000 (red)
- MRD: 7.0mg/kg or 3.2mg/lb (500mg total)
- pregnancy risk: B
- precautions: ASA 3, 4, CV disease, etc.
___ is the “gold standard” for use in both medicine and dentistry
lidocaine aka xylocaine
what is the alternative name, classification, metabolism, excretion, duration, onset of action, formulation w/epi, MRD, pregnancy risk, and precautions of 3% mepivicaine, plain?
- aka carbocaine, polocaine
- classification: amide
- metabolism: hepatic
- excretion: renal
- duration: short
- pulpal: approx. 20-40 minutes
- soft tissues: approx 2-3 hours
- onset of action: 3-5 minutes
- formulation w/epi: none (satin gold band)
- MRD: 6.6mg/kg or 3.0mg/lb (400mg total)
- pregnancy risk: C
- precautions: accidental overdose due to being a plain formulation
what is the alternative name, classification, metabolism, excretion, duration, onset of action, formulation w/epi, MRD, pregnancy risk, and precautions of 4% prilocaine, plain?
- aka citanest
- classification: amide
- metabolism: hepatic and pulmonary
- excretion: renal (almost completely excreted as metabolites)
- duration: intermediate
- pulpal: approx 10-15 minutes by infiltration, 40-60 nerve block
- soft tissues: 1.5-2 hours by infiltration, 2-3 hours by nerve block
- onset of action: 3-5 minutes
- formulation w/epi: plain (black band), 1:200,000 (yellow band)
- MRD: 8.0mg/kg or 3.6mg/lb (600mg total)
- pregnancy risk: C
- precautions: contraindicated in patients with idiopathic or congenital methemoglobinemia or patients with any type of anemia; cardiac or respiratory failure by hypoxia
what is the alternative name, classification, metabolism, excretion, duration, onset of action, formulation w/epi, MRD, pregnancy risk, and precautions of 4% articaine, 1:100,000 epi?
- aka septocaine
- classification: hybrid but classified as an amide
- metabolism: hepatic and plasma
- excretion: renal (almost completely excreted as metabolites)
- duration: intermediate
- pulpal: approx 60-75 minutes
- soft tissues: approx 1.5-3 hours
- onset of action:
- local infiltration: 1-2 minutes
- mandibular block: 2-2.5 minutes
- formulation w/epi: 1:100,000 and 1:200,000 (glossy gold)
- MRD: 7.0mg/kg or 3.2mg/lg (500mg total, book says no absolute maximum)
- pregnancy risk: C
- precautions: use on children younger than 4 is not recommended
what is the alternative name, classification, metabolism, excretion, duration, onset of action, formulation w/epi, MRD, pregnancy risk, and precautions of 0.5% bupivacaine, 1:200,000 epi?
- aka marcaine
- classification: amide
- metabolism: hepatic
- excretion: renal (almost completely excreted as metabolites)
- duration: long
- pulpal: approx 90-180 minutes
- soft tissues: approx 4-9 hours
- onset of action: 6-10 minutes
- formulation w/epi: 1:200,000 (blue band)
- MRD: 2.0mg/kg or 0.9mg/lb (90mg total)
- pregnancy risk: C
- precautions: contraindicated in pediatric patients and the elderly; cardiotoxic
___ is great to use on patients with severe cardiovascular issues
3% mepivicaine, plain
aka carbocaine, polocaine
___ has the longest duration of action of all the local anesthetics
0.5% bupivacaine, 1:200,000 epi
___ is extremely cardiotoxic; it has a higher affinity for LA receptor sites than other LAs and can cause MI that is resistant to resuscitaiton
0.5% bupivacaine 1:200,000 epi
aka marcaine
this is why it should never be administered to children and the elderly
what is oraverse?
powerful vasodilator that is injected into the same site and helps flush the LA in an attempt to reverse the numbness reaction of the LA
causes vasodilation to allow the LA to travel systemically
oraverse is a ___ml cartridge that contains ___mg of phentolamine mesylate
- 1.7
- 0.4
what is the dosing of oraverse?
1:1 (1 oraverse per cartridge injected)
what is the max dose for oraverse?
- 2 cartridges for adults and adolescents 12 years of age and older
- 1 cartridge for patients 6-11 years of age and over 66lbs
- 1/2 cartridge for children 6-11 years of age and weighing 33-66lbs
what is the elimination half life of oraverse?
2-3 hours
what is the pregnancy risk for oraverse?
C
what are the precautions for oraverse?
not recommended for children under 6 or below 33lbs
what is the ADA criteria for acceptable LA syringes?
durability, versatility, inexpensive, aspiration friendly
what are the 5 different types of syringes used in dentistry?
- breech-loading (can be loaded from the side), metallic (important for sterilization), cartridge-type, aspirating
- breech-loading, metallic, cartridge-type, self-aspirating
- pressure-type
- needleless-type
- C-CLAD-type
describe the breech-loading, metallic, cartridge-type, aspirating syringe
- allows for side-loading of the cartridge
- allows for user-controlled aspiration
- allows for visualization of cartridge
describe the breech-loading, metallic, cartridge-type, self-aspirating syringe
- uses elasticity of rubber diaphragm in the anesthetic cartridge to obtain negative pressure for aspiration
- you press on thumb ring
describe pressure syringes
- allows for increased pressure during injection
- works almost like a caulk gun
- depends on mechanics of instrument rather than pressure provided by operator
- ideal for PDL/intraligamentary injections
describe needleless injectors
liquid is injected into target tissues using extremely high pressure
describe electronically controlled syringes
- can administer anesthetic slowly
- greater control of quantity and speed
- great for kids; doesn’t look like a needle
most glass cartridges (aka carpules) contain approximately 1.8ml of anesthetic solution, exception for septodont products, which list ___ml
1.7
what are the 4 parts of the cartridge?
glass tube, stopper (plunger), aluminum cap, rubber diaphragm
what are the different needle lengths?
- ultra-short - 10-12mm long
- short - 20-25mm long
- long - 30-35mm long
what are the most commonly used needle sizes in dentistry?
- 30-gauge short
- 27-gauge long
- 25-gauge long or short
___ refers to the diameter of the lumen of the needle
gauge
the smaller the number, the greater the diameter
“larger gauge” refers to a larger diameter
“smaller gauge” refers to a smaller diameter
do larger or smaller diameter needles have less deflection when passing through tissues?
larger needles
- less deflection means greater accuracy during needle insertion
- the hope is that this will lead to greater success in providing LA
the greater the angle of the needle bevel, the ___ the deflection
greater
___ the needle as it enters soft tissues can significantly reduce the amount of tissue deflection
rotating
this is the bi-rotational insertion technique (BRIT)
- neutralizes perpendicular forces that are responsible for deflection
- performed by rotating the needle in a back and forth rotational movement while advancing the needle through soft tissue
___ is the act of inserting the needle into the target tissue, and then pulling back on the plunger prior to delivery of local anesthetic
aspiration
what is the purpose of aspiration?
to evaluate the cartridge for the presence of blood in order to avoid accidental intra-arterial injection of LA
aspiration of blood has been demonstrated to be easier and more reliable to perform through the use of a ___ needle than a ___ one
larger, smaller
smaller gauge needles increase the likelihood of the harpoon dislodging from the rubber plunger prior to completing aspiration
the ___ is the most common point of needle breakage
hub
why is the hub the weakest point of the needle?
because is it metal connected to plastic
also due to cyclic fatigue because most dentists will bend the needle at the hub; if you need to bend the needle, be sure to bend it further up from the hub
are smaller or larger diameter needles more likely to break?
smaller
needles should be changed after approximately how many tissue penetrations on the same patient?
3-4
___ are used to prepare the tissues at the injection site prior to initial needle penetration
topical anesthetic
what should you do to the tissues prior to placing topical anesthetic?
dry the tissues using sterile gauze
topical anesthetic should be placed on tissue for approx how long?
60 seconds, although 2-3 minutes can lead to more profound soft tissue analgesia
why should topical anesthetics that contain alcohol be avoided?
potential for tissue irritation
