What is the mechanism of action of local anesthesia?
Show answer
Local anesthesia works by blocking the transmission of nerve impulses, typically by binding to voltage-gated sodium channels.
2
What are the pharmacokinetics and pharmacodynamics of local anesthesia?
Show answer
Pharmacokinetics refers to how the body processes the drug, including absorption, distribution, metabolism, and excretion. Pharmacodynamics describes the effects of the drug on the body.
3
What is the calculation of the Maximum recommended dosage for local anesthesia?
Show answer
The maximum recommended dosage for local anesthesia is typically calculated based on the patient's weight and the type of local anesthetic used.
4
What is local anesthesia?
Show answer
A type of anesthesia that numbs a specific area of the body to prevent pain during a procedure.
5
Who was Francis Rynd and what did he invent?
Show answer
Francis Rynd was a physician who invented the hollow needle, which is a key component in the development of local anesthesia.
6
What was the year of the first successful use of local anesthesia?
Show answer
1844, when Francis Rynd used the hollow needle for the first time.
7
What are the two main types of local anesthetics mentioned in the slide?
Show answer
Esters and Amides
8
Which types of local anesthetics are no longer available in dental cartridges due to risk of allergic reactions?
Show answer
Esters
9
What are the desirable properties of injectable local anesthetics?
Show answer
Can induce a transient and completely reversible state of anesthesia, does not cause permanent nerve damage, low systemic toxicity, available in sterile form, stable in solution, non-irritating, short onset, and relatively hypoallergenic.
10
What is the purpose of formulating local anesthetics as a hydrochloride salt?
Show answer
To enhance their stability in solution.
11
What is the difference between ester-linked and amide-linked local anesthetics?
Show answer
Ester-linked local anesthetics have an ester linkage, while amide-linked local anesthetics have an amide linkage.
12
What are the key components of a local anesthetic molecule?
Show answer
The key components are the lipophilic aromatic group, the hydrophilic tertiary amine, and the ester or amide linkage.
13
What is the difference between the basic form and the protonated (acidic) form of an ester-linked local anesthetic?
Show answer
The basic form is lipophilic, while the protonated (acidic) form is hydrophilic.
14
How does the pH of the local environment affect the dissociation state of an amide-linked local anesthetic?
Show answer
The pH shifts the equilibrium to the ionized or nonionized forms of the amide-linked local anesthetic.
15
What is the pKa range for local anesthetics?
Show answer
7.5-10
16
What happens when pKa equals pH?
Show answer
Concentrations of the protonated and non-protonated forms are equal
17
How does an acidic pH affect the efficacy of local anesthetics?
Show answer
It shifts the equilibrium towards more protonation, decreasing efficacy
18
What are nociceptors and thermoreceptors and how do they function in pain transmission?
Show answer
Nociceptors and thermoreceptors are sensory receptors that detect pain and thermal stimuli, respectively. They activate when stimulated, generating an action potential and transmitting the signal to the somatosensory cortex through the dorsal horn of the spinal cord.
19
How do local anesthetics inhibit the conduction of action potential?
Show answer
Local anesthetics inhibit the conduction of action potential in all afferent nerve fibers in and around the injection site by blocking the sodium channels.
20
What is the mechanism of action of local anesthetics?
Show answer
Local anesthetics prevent pain perception by binding to specific receptors and blocking sodium channels, which stops sodium influx and prevents depolarization or action potential generation.
21
What are the stages of sodium channel activation?
Show answer
The stages of sodium channel activation are Closed, Depolarized, Open, and Inactive.
22
What factors influence the onset of local anesthetic (LA) action?
Show answer
Size and lipophilicity of the LA, dissociation constant (pKa) near physiological pH.
23
How does vasodilator activity affect the duration of local anesthetic action?
Show answer
Increased blood flow will increase diffusion, thus affecting the duration of action.
24
What is the anatomical proximity to the injection site?
Show answer
The distance from the injection site to the nerve fibers.
25
What is differential functional blockade?
Show answer
It refers to the varying susceptibility of nerve fibers to block local anesthetics.
26
What is the function of Type A alpha fibers?
Show answer
Proprioception, motor
27
Which type of nerve fiber is most susceptible to local anesthetics?
Show answer
Type C
28
What is the conduction velocity of Type A alpha fibers?
Show answer
70-120 m/s
29
What is the pKa of Benzocaine?
Show answer
3.5
30
What percentage of the base form of Benzocaine is present at pH 7.4?
Show answer
100%
31
Which local anesthetic has the longest onset time?
Show answer
Bupivacaine
32
What is Local Anesthetic Systemic Toxicity (LAST) and what is its incidence rate?
Show answer
LAST is a rare but possible and life-threatening event with an incidence rate of 0.03%.
33
What are the initial signs of systemic toxicity in LAST?
Show answer
The initial signs include agitation, confusion, and dizziness.
34
What are the progression stages of LAST and their corresponding serum concentrations?
Show answer
Progression stages include seizures at 10 ug/ml, coma at 15 ug/ml, respiratory failure at 20 ug/ml, and cardiovascular collapse at >20 ug/ml.
35
What is the most common cause of Local Anesthetic Systemic Toxicity (LAST)?
Show answer
Accidental intravascular injection during the administration of local anesthetics.
36
What is the importance of aspiration before every injection?
Show answer
To prevent accidental intravascular injection.
37
What are some co-morbidities that can increase the risk of local anesthetic overdose?
Show answer
Hepatic dysfunction.
38
What are the initial management steps for Local Anesthetic Systemic Toxicity (LAST)?
Show answer
Airway management, circulatory support, and calling for help.
39
What medication can be administered by EMS to manage convulsions in cases of LAST?
Show answer
Benzodiazepines.
40
What is the lipid rescue treatment for patients exhibiting seizures or signs of CVS toxicity?
Show answer
20% Lipid emulsion (triglycerides and phospholipid) infusion.
41
What is an ester?
Show answer
A chemical compound formed by the reaction of an acid and an alcohol, with the removal of water.
42
What are the key characteristics of esters?
Show answer
Esters have a sweet, fruity smell and are commonly used in perfumes and flavorings.
43
What is the primary metabolite of benzocaine?
Show answer
Para-aminobenzoic acid (PABA)
44
How is benzocaine applied and what is its absorption rate?
Show answer
Benzocaine is applied to mucous membranes as a topical anesthetic and is poorly absorbed into the circulation.
45
What is the onset of action for Procaine (NovocainĀ®)?
Show answer
6-10 minutes
46
What is the duration of action for Procaine (NovocainĀ®)?
Show answer
15-60 minutes
47
What is the onset of action for Chloroprocaine (NesacaineĀ®)?
Show answer
5-15 minutes
48
What is the duration of action for Chloroprocaine (NesacaineĀ®)?
Show answer
30-90 minutes
49
How is Chloroprocaine (NesacaineĀ®) administered?
Show answer
Via the epidural route
50
What is the primary use of Tetracaine (Tetracaine HCl)?
Show answer
Spinal anesthesia
51
What are amides?
Show answer
Amides are a type of organic compound derived from carboxylic acids and amines.
52
What is the general formula for an amide?
Show answer
The general formula for an amide is R-CO-NR'.
53
What factors influence the absorption and distribution of local anesthetics?
Show answer
Lipid solubility, vascularity, protein binding, pKa, and additives like epinephrine.
54
What are the key terms associated with the pharmacokinetics of local anesthetics?
Show answer
Absorption and distribution, lipid solubility, vascularity, protein binding, pKa, and additives.
55
What enzymes metabolize lidocaine and mepivacaine in the liver?
Show answer
Microsomal cytochrome P-450 enzymes
56
What are the active metabolites produced from lidocaine?
Show answer
Monoethylglycylxylidide (M.E.G.X.) and glycylxylidide (G.X.)
57
How is prilocaine metabolized?
Show answer
In both the liver and kidneys via amidases
58
What is the primary organ where Bupivacaine is metabolized?
Show answer
Liver
59
What are the main enzymes involved in the metabolism of Bupivacaine?
Show answer
Amidases
60
What is the main organ where Articaine is metabolized?
Show answer
Blood
61
Which enzymes are involved in the metabolism of Articaine in the liver?
Show answer
CYP enzymes
62
What is the primary organ for the excretion of metabolites?
Show answer
Kidneys
63
What is the range of elimination half-life for Amide LAs?
Show answer
20 minutes to few hours
64
Which Amide LAs can be suitable for patients with renal dysfunction?
Show answer
Those that undergo liver/plasma metabolism to inactive metabolites prior to excretion
65
What are the proprietary names for Articaine HCl?
Show answer
Articadent, Orabloc, Septocaine, Zorcaine
66
What are the proprietary names for Bupivacaine HCl?
Show answer
Marcaine, Vivacaine
67
What are the proprietary names for Lidocaine HCl?
Show answer
Lignospan, Octocaine, Xylocaine
68
What is the prototype of the amide class of local anesthetics?
Show answer
Lidocaine Hydrochloride
69
What is the absolute maximum dose of lidocaine per appointment?
Show answer
500 mg
70
How does lidocaine compare to other local anesthetics in terms of vasodilation properties?
Show answer
Lidocaine has moderate vasodilation properties, which are less than prilocaine or mepivacaine, but more than bupivacaine and procaine.
71
What is the rapid onset of action for Mepivacaine Hydrochloride?
Show answer
3-5 minutes
72
What is the absolute maximum dose of Mepivacaine Hydrochloride per appointment?
Show answer
400 mg
73
Does Mepivacaine Hydrochloride produce vasoconstriction?
Show answer
Slight vasoconstriction
74
What is the onset of action for Prilocaine Hydrochloride?
Show answer
3-5 minutes
75
What is the absolute maximum dose of Prilocaine Hydrochloride?
Show answer
600 mg
76
What is the duration of action for Prilocaine Hydrochloride without a vasoconstrictor?
Show answer
10 minutes
77
What is the onset time of Articaine Hydrochloride?
Show answer
1-6 minutes
78
What is the half-life of Articaine Hydrochloride?
Show answer
20 minutes
79
What are the two main groups in the chemical structure of Articaine Hydrochloride?
Show answer
Ester and amide groups
80
What is the moderate onset time for Bupivacaine Hydrochloride?
Show answer
2-10 minutes
81
What is the absolute maximum dose of Bupivacaine Hydrochloride per appointment?
Show answer
90 mg
82
How is Bupivacaine Hydrochloride metabolized and excreted?
Show answer
Metabolized in the liver by amidases and excreted via the kidneys
83
What are dental cartilages?
Show answer
Dental cartilages are specialized connective tissues that form the framework of the teeth and surrounding structures.
84
What is the function of dental cartilages?
Show answer
Dental cartilages provide support and cushioning for the teeth and surrounding structures.
85
What is the color coding system for local anesthetic cartridges as per the American Dental Association Council on Scientific Affairs?
Show answer
The color coding system includes: Gold for Articaine HCl 4% with epinephrine 1:100,000, Blue for Bupivacaine 0.5% with epinephrine 1:200,000, Light blue for Lidocaine HCl 2%, Green for Lidocaine HCl 2% with epinephrine 1:50,000, Red for Lidocaine HCl 2% with epinephrine 1:100,000, Tan for Mepivacaine HCl 3%, Brown for Mepivacaine HCl 2% with levonordefrin 1:20,000, Black for Prilocaine HCl 4%, and Yellow for Prilocaine HCl 4% with epinephrine 1:200,000.
86
What is the purpose of the color-coded band on local anesthetic cartridges?
Show answer
The color-coded band on local anesthetic cartridges is used to identify the type of local anesthetic solution and its concentration.
87
What are the components of a dental cartridge (LA Solution)?
Show answer
Local anesthetic agent, vasoconstrictors, reducing agents, preservatives, fungicide, and vehicle.
88
What is the pH range for LA with vasoconstrictors compared to LA without vasoconstrictors?
Show answer
LA with vasoconstrictors are more acidic (around 3.5) compared to LA without vasoconstrictors (around 6.5).
89
What is the purpose of LA buffering in dental procedures?
Show answer
To increase the onset of action and enhance patient comfort by bringing the solution near the physiological pH.
90
What is the pKa range for local anesthetics (LA)?
Show answer
7-10
91
What is the concentration of the lidocaine used in the study?
Show answer
2%
92
What is the ratio of epinephrine used in the study?
Show answer
1:100,000
93
When was the study published?
Show answer
February 2013
94
What is a vasoconstrictor?
Show answer
A vasoconstrictor is a substance that causes blood vessels to narrow.
95
What is the purpose of using vasoconstrictors with local anesthesia?
Show answer
To reduce bleeding and prolong the effect of local anesthesia.
96
What is vasodilation and how does it affect local anesthesia?
Show answer
Vasodilation causes redistribution of local anesthetic, leading to higher plasma concentration, decreased depth and duration of anesthesia, and increased bleeding risk at the injection site.
97
What are vasoconstrictors and what do they do?
Show answer
Vasoconstrictors, including epinephrine and levonordefrin, help control the impact of local anesthetic-associated vasodilation.
98
What is vasoconstriction and what are its effects?
Show answer
Vasoconstriction is the narrowing of blood vessels. Its effects include decreasing blood flow to the injection site, reducing local anesthesia redistribution, lowering the risk of systemic side effects, decreasing the risk of bleeding, and increasing the duration of the anesthetic action.
99
List the effects of vasoconstriction on local anesthesia.
Show answer
Decrease blood flow to the injection site, decrease local anesthesia redistribution, decrease risk of systemic side effects, decrease risk of bleeding, increase duration of anesthetic action.
100
What are the effects of epinephrine on the cardiovascular system?
Show answer
Epinephrine increases cardiac output and blood pressure.
101
What is the dilution of epinephrine used as a hemostatic reagent?
Show answer
1:50,000
102
What are the CNS symptoms of epinephrine overdose?
Show answer
Fear, anxiety, restlessness, throbbing headache, tremor, and dizziness.
103
What is the effect of increasing the concentration of epinephrine on the duration of local anesthesia?
Show answer
Increasing the concentration of epinephrine decreases the duration of local anesthesia.
104
What is the maximum duration of local anesthesia for Lidocaine 2% with Epinephrine 1:50,000?
Show answer
210 minutes
105
What is the maximum dose of epinephrine in local anesthesia for a healthy subject?
Show answer
0.2 mg
106
What is the maximum dose of epinephrine in local anesthesia for a patient with severe cardiovascular disease (ASA III and IV)?
Show answer
0.04 mg
107
What is the recommended maximum recommended dose (MRD) for epinephrine-sensitive individuals (ASA category III patients)?
Show answer
40 Ī¼g per appointment
108
What is the American Society of Anesthesiologists' Physical Status Classification system?
Show answer
A grading system used to assess the physical status of a patient before surgery.
109
What are the five categories in the ASA Physical Status Classification system?
Show answer
ASA I, ASA II, ASA III, ASA IV, and ASA V.
110
What does ASA I represent in the Physical Status Classification system?
Show answer
A patient with no known systemic disease.
111
What is the effect of epinephrine on blood glucose levels in diabetic patients who do not use their hypoglycemic medication?
Show answer
Epinephrine may increase blood glucose levels.
112
What is glycogenolysis?
Show answer
The breakdown of glycogen into glucose.
113
What is Levonordefrin?
Show answer
A synthetic vasoconstrictor that mainly acts by Ī±2 receptor stimulation.
114
How does Levonordefrin affect the heart and central nervous system?
Show answer
It has lower cardiac and CNS stimulation.
115
What is the dilution ratio of Levonordefrin when combined with mepivacaine?
Show answer
1:20,000
116
What is the FDA risk category for lidocaine and prilocaine during pregnancy?
Show answer
B
117
Which amide local anesthetics have FDA risk category B during pregnancy?
Show answer
Lidocaine and prilocaine
118
What is the maximum total dosage of lidocaine with vasoconstrictors?
Show answer
500 mg
119
What is the mechanism of action of Phentolamine Mesylate (OraVerse)?
Show answer
It is an alpha-adrenergic antagonist that decreases local anesthetic duration by inducing vasodilation.
120
How is Phentolamine Mesylate (OraVerse) dispensed and used?
Show answer
It is dispensed as 0.4 mg/1.7 ml cartridges and used in a 1:1 ratio as a reversal agent for local anesthetics.
121
What are the indications for using a specific medication?
Show answer
Reverse local anesthesia and soft tissue numbness, shorten time to regain normal sensations, and prevent self-inflicted soft-tissue trauma in children or patients with cognitive impairments.
122
What are the side effects of the medication?
Show answer
Injection site pain, cardiovascular system effects (hypertension, bradycardia), and headache.
123
What is tachyphylaxis in the context of local anesthesia (LA)?
Show answer
Tachyphylaxis is a condition where the nerve function returns before re-injection of LA, leading to pain in the patient.
124
How can tachyphylaxis be prevented?
Show answer
To prevent tachyphylaxis, additional LA injections are administered before the full recovery of nerve function.
125
What are the common contraindications for local anesthetics (LA)?
Show answer
LA allergy and bisulfite allergy.
126
What precaution should be taken when using prilocaine with patients who have G6PD deficiency?
Show answer
Avoid using prilocaine with patients who have G6PD deficiency.
127
What is the precaution for patients with hyperthyroidism or ASA III/IV patients regarding epinephrine concentration?
Show answer
Use high epinephrine concentration cautiously.
128
What are GABA receptors and how do they work in the context of general anesthesia?
Show answer
GABA receptors are inhibitory neurotransmitters that, when stimulated, help induce general anesthesia by reducing neural activity.
129
What are NMDA receptors and how do they relate to general anesthesia?
Show answer
NMDA receptors are excitatory receptors that, when blocked, contribute to the mechanism of action of general anesthetics in inducing anesthesia.
130
What are the four goals of general anesthesia?
Show answer
Hypnosis, Analgesia, Amnesia, Muscle relaxation
131
What is the first stage of general anesthesia?
Show answer
Induction
132
What is the second stage of general anesthesia?
Show answer
Maintenance
133
What is the maximum recommended dose (MRD) of Mepivacaine for Patient A?
Show answer
6.6 mg/kg
134
How many cartridges of Mepivacaine HCl can be administered to Patient A?
Show answer
1 cartridge
135
What is local anesthesia?
Show answer
A type of anesthesia that numbs a specific area of the body to prevent pain during a procedure.
136
Which book is recommended for understanding the pathophysiology of drug therapy?
Show answer
Principles of Pharmacology: The Pathophysiologic Basis of Drug Therapy