Local Anesthesia for the Dental Hygienist, 1e 1st Edition by Logothetis -Test Bank

Logothetis: Local Anesthesia for the Dental Hygienist Chapter 03: Pharmacology of Local Anesthetic Agents Test Bank TRUE/FALSE 1. Prilocaine is biotransformed in the liver only. ANS: F Correct: Prilocaine is biotransformed in the lungs and the liver. REF: Page 44 2. The most potent local anesthetic is bupivacaine which has the greatest degree of lipid solubility. ANS: T REF: Page 46 3. Intravascular injections significantly increase the possibility of an overdose. ANS: T REF: Page 46 4. The higher the pKa of an anesthetic, the faster the onset of action. ANS: F Correct: The higher the pKa of the anesthetic, the slower the onset of action. REF: Page 46 5. The speed of recovery from local anesthetic is determined by the degree of binding to the receptor site of each anesthetic. ANS: T REF: Page 46 6. Local anesthetics are vasoconstrictors and decrease the absorption of the drug by the blood. ANS: F Correct: Local anesthetics are vasodilators and increase the absorption of the drug by the blood. REF: Page 46 7. If more anesthetic is needed for a procedure, it is important to reinject the anesthetic after the mantel fibers have fully recovered. ANS: F Correct: If more anesthetic is needed for a procedure, it is important to reinject the anesthetic before the mantel fibers have fully recovered. REF: Page 46 8. Local anesthetics affect the CNS and CVS after biotransformation. ANS: F Correct: Local anesthetics affect the CNS and CVS before biotransformation. REF: Page 46 9. The rate of systemic absorption of local anesthetics depends on the total dose, concentration, route of administration, vascularity of tissues, and presence or absence of a vasoconstrictor. ANS: T REF: Page 46 10. Local anesthetics easily cross the blood-brain barrier. ANS: T REF: Page 46 MULTIPLE CHOICE 1. What is the significant clinical difference between esters and amides? a. Potential for allergic reactions b. Cross-hypersensitivity c. Lipid solubility d. Drug potency ANS: A The significant clinical difference between esters and amides is the potential for allergic reactions. REF: Page 44 2. Which component of the local anesthetic molecule improves the lipid solubility, which facilitates the penetration of the anesthetic through the lipid-rich membrane where the receptor sites are located? a. Hydrophilic amino group b. Intermediate hydrocarbon ester or amide chain c. Lipophilic aromatic ring d. All of the above ANS: C The lipophilic aromatic ring improves the lipid solubility of the molecule, which facilitates the penetration of the anesthetic through the lipid rich-membrane where the receptor sites are located. REF: Page 37 3. Which component of the local anesthetic molecule renders the molecule water soluble? a. Hydrophilic amino group b. Intermediate hydrocarbon ester or amide chain c. Lipophilic aromatic ring d. All of the above ANS: A The hydrophilic amino group renders the molecule water soluble. REF: Page 37 4. Dissociation constant refers to which of the following descriptions? a. Determines the portion of administered anesthetic dose in the lipid-soluble state (RN) b. Determines the onset of anesthetic action as the increase of molecules crossing the nerve membrane decreases the time of the anesthetic’s onset c. The pH at which 50% of the molecules exist in the lipid-soluble form and 50% in the water-soluble form d. All of the above ANS: D All of the statements above describe the phenomenon of dissociation constant. REF: Pages 39, 40 and Table 3-1 5. Why is lipid solubility an important characteristic of local anesthetic drugs? a. A greater lipid solubility enhances the diffusion of the anesthetic drug through the nerve. b. A greater lipid solubility indicates a higher potency of the anesthetic drug. c. A greater lipid solubility allows for a lower effective dose of the local anesthetic drug. d. All of the above. ANS: D All of the statements above describe the importance of the characteristic of lipid solubility of the local anesthetic drugs. REF: Page 39, Table 3-1 6. Why is protein binding an important characteristic of local anesthetic drugs? a. Increased protein binding allows more cations (RNH+) to bind to the receptor sites within the sodium channels, prolonging the presence of anesthetic at the site of action. b. Increased protein binding allows more RN molecules to bind to the receptor sites within the sodium channels, prolonging the presence of anesthetic at the site of action. c. Decreased protein binding allows more cations (RNH+) to bind to the receptor sites within the sodium channels, prolonging the presence of anesthetic at the site of action. d. Decreased protein binding allows more RN molecules to bind to the receptor sites within the sodium channels, prolonging the presence of anesthetic at the site of action. ANS: A Increased protein binding allows more cations (RNH+) to bind to the receptor sites within the sodium channels, prolonging the presence of anesthetic at the site of action. REF: Page 38, Table 3-1 7. What characteristic of local anesthetic drugs determines the speed of nerve recovery? a. The concentration of the local anesthetic b. The degree of lipid solubility c. The degree of protein binding d. The nonnervous tissue diffusibility ANS: C The degree of protein binding at the receptor site for each anesthetic determines the speed of nerve recovery. REF: Page 43, Table 3-1 8. What does the membrane expansion theory of the action of local anesthetics suggest? a. Anesthetics that are highly hydrophilic cause the matrix of the nerve membrane to expand, narrowing the sodium channels, thus preventing depolarization. b. Anesthetics that are highly lipid soluble cause the lipoprotein matrix of the nerve membrane to expand, narrowing the sodium channels, thus preventing depolarization. c. Anesthetics cause the sodium channels to expand, thus allowing the increase in protein binding within the channels. d. All of the above ANS: B The membrane expansion theory suggests that anesthetics that are highly lipid soluble cause the lipoprotein matrix of the nerve membrane to expand, narrowing the sodium channels, thus preventing depolarization. REF: Page 41 9. What does the specific protein receptor theory of the action of local anesthetics suggest? a. The specific protein receptor theory suggests that anesthetics that are highly lipid soluble cause the lipoprotein matrix of the nerve membrane to expand, narrowing the sodium channels, thus preventing depolarization. b. The method by which the impulses travel down the length of the nerve affects whether nodes of Ranvier are stimulated or not. c. Displaced Ca++ and local anesthetic drugs compete to bind to receptor sites within the ion channels of cell membranes. d. All of the above ANS: C During depolarization, Ca++ are displaced and are thought to be the most significant factor responsible for the influx of sodium into the nerve. During slow depolarization, local anesthetics work by competing with Ca++ to bind to these ion channels. REF: Page 40 10. Tachyphylaxis is a term used to describe what phenomenon? a. An increased tolerance to a drug that is administered repeatedly. b. If the dental procedure lasts longer than the duration of the anesthetic and the mantel and core fibers have fully recovered, the reinjection of local anesthetic will be ineffective. c. Once the mantel fibers return to function, the patient experiences pain yet administration of anesthetic does not alleviate the pain. d. All of the above ANS: D All of the above describe the phenomenon of tachyphylaxis. REF: Pages 36, 43 11. What factor/factors influence the duration of the effects of local anesthetics? a. Degree of protein binding b. Vascularity of injection site c. Addition or absence of a vasoconstrictor d. All of the above ANS: D The duration of local anesthetics is influenced by the degree to which the local anesthetic is bound to the receptor sites or the protein binding; the vascularity of the injection site; and the addition or absence of an added vasoconstrictor to the local anesthetic. REF: Page 43 12. What is the purpose of adding a vasoconstrictor to the local anesthetic? a. To increase the rate of absorption of the anesthetic b. To reduce the rate of absorption of the anesthetic c. To reduce systemic toxicity d. To increase hemostasis ANS: B To reduce the rate of absorption, vasoconstrictors are added to local anesthetics. REF: Page 43 13. Which organs of the body will have higher concentrations of anesthetics? a. High vascular organs b. Low vascular organs c. Brain, heart, liver, kidneys, lungs d. Some combination of the above ANS: D High vascular organs such as the brain, heart, liver, kidneys, and lungs will have higher concentrations of anesthetics. REF: Page 43 14. What is another name for the elimination of the local anesthetic from the blood and tissues? a. Tachyphylaxis b. Dissociation constant c. Half-life d. Distribution barriers ANS: C Another name for the elimination of the local anesthetic from the blood and tissues is the half-life of the anesthetic. REF: Page 44 15. Which part of the chemical structure of a local anesthetic determines the pattern of biotransformation of the anesthetic? a. Lipophilic part b. Hydrophilic part c. Intermediate chain d. All of the above ANS: C The intermediate chain determines the pattern of biotransformation of the anesthetic. REF: Page 44 16. What is the inability to hydrolyze ester local anesthetics and other chemically related drugs called? a. Atypical pseudocholinesterase b. Low hepatic dysfunction c. Para-aminobenzoic acid intolerance d. None of the above ANS: A The inability to hydrolyze ester local anesthetics and other chemically related drugs is called atypical pseudocholinesterase. REF: Page 44 17. Esters, benzocaine, tetracaine, and procaine are hydrolyzed in the plasma by the enzyme pseudocholinesterase and by liver esterases. Procaine is metabolized to PABA and is the major metabolic byproduct responsible for allergic reactions. a. Both statements are true. b. Both statements are false. c. The first statement is true; the second statement is false. d. The first statement is false; the second statement is true. ANS: A Both statements are true. REF: Page 44 18. What factor/factors determine the severity of an overdose reaction to local anesthetic? a. Degree of drop in blood pressure b. Time lapse between the administering of the local anesthetic to the overdose c. Number of symptoms patient experiences d. All of the above ANS: B The time lapse between the administering of the local anesthetic to the overdose reaction determines its severity. REF: Page 45 19. Which anesthetic drug has a short half-life of 45 minutes and is the least toxic of the anesthetics? a. Articaine b. Lidocaine c. Mepivacaine d. Prilocaine ANS: A Articaine has a short half life of 45 minutes and is the least toxic of the anesthetics. REF: Page 44 Answer the following questions based upon the following case study. Sam, a businessman who travels extensively, has been in your dental chair for 2 hours for extensive nonsurgical perio procedures. He insisted on having a long appointment in order “to get everything done at one time.” A review of Sam’s health history reveals that he is taking medications for high blood pressure; has no known allergies; recently quit smoking; and is a recovering alcoholic. He mentions that he is going through a divorce and that he is leaving for China within the week. You explain to Sam that, because of the long appointment and the amount of work that you need to accomplish, you will use a long-lasting local anesthetic to ensure his comfort. You apply topical benzocaine to all injection sites on the right side. You choose to administer the local anesthetic bupivacaine because of its long-lasting effect. Although Sam is a good-natured patient, you experience difficulty in achieving the desired level of anesthesia in order to keep Sam comfortable. Within 5 minutes of the administration of yet another cartridge of anesthetic, Sam begins to complain of a headache and you notice that he is slurring his words. You quickly retake his blood pressure only to discover that it has actually gone down since the beginning of the appointment. What thoughts should be going through your mind at this time? 20. Based on Sam’s physical symptoms, what should you consider? a. Sam is extremely relaxed and his blood pressure medication is working. b. Sam is extremely stressed. c. Sam may be experiencing a mild overdose to the anesthetic. d. Sam may be experiencing a cardiovascular crisis. ANS: D Symptoms of an overdose on the cardiovascular system include headache and increased slurring of speech. REF: Page 45, Table 3-7 21. Why do you think Sam’s blood pressure decreased from the beginning of the appointment? a. Sam became more comfortable during the appointment. b. Symptoms of a CNS and CVS overdose are biphasic. c. Symptoms of a possible overdose change from a depression phase to a stimulation phase. d. Some combination of the above ANS: D Choices a and b are correct. When patients become more comfortable and less apprehensive with dental procedures, a drop in blood pressure may be noted. However, in Sam’s case, the fact that he began experiencing a headache immediately after another injection combined with the noticeable drop in blood pressure should lead one to think about the possibility of an anesthetic drug overdose. Symptoms of a CNS and CVS overdose are biphasic, meaning that they progress from a stimulation phase to a depression phase. REF: Page 45 22. Considering Sam’s health history, what anesthetic drug may have been a better choice? a. Procaine b. Articaine with epinephrine c. Lidocaine d. Mepivacaine ANS: B Consider that Sam is a recovering alcoholic who may or may not have liver damage. Because only about 10% of articaine is biotransformed in the liver, it may, at first, appear to be a better choice for Sam; however, due to its half-life, more anesthetic would be required in the long run to keep Sam comfortable, thus making articaine an unacceptable choice. BUT the addition of a vasoconstrictor such as epinephrine to the articaine changes this situation. The vasoconstrictor will delay the absorption of the local anesthetic into the tissue, thus prolonging tissue anesthesia and allowing the dental hygienist to work longer. This illustrates the range of considerations that affect local anesthetic selection. REF: Pages 45, 46 23. Reflecting on your experience with Sam, what other factors may contribute to an incident similar to Sam’s? a. The use of topical anesthetics plus intravascular injections b. An injection that is administered too rapidly c. The perio infection and inflammation d. All of the above ANS: D All of the above. Reflecting on one’s technique of administering anesthetic drugs and working to improve that technique can prevent further incidents such as Sam’s. Intravascular injections rapidly produce high blood levels and topical anesthetics are administered in high concentrations that are absorbed quickly from the site of administration: both techniques increase the possibility of toxicity. The rate of injection can increase the chance of toxicity because tissues cannot accept the large, rapid volume of anesthetic. Vascular areas due to infection, inflammation, or vasodilation from the local anesthetic agent will increase systemic toxicity. REF: Page 45 Logothetis: Local Anesthesia for the Dental Hygienist Chapter 06: Topical Anesthetic Agents Test Bank ESSAY 1. List common forms of topical anesthetics used in dentistry. ANS: Gel, spray, liquid, ointment, and one patch form REF: Page 94 and Table 6-1 2. List the methods for delivery of topical anesthetic drugs. ANS: Cotton tip applicators, sprays, brushes, patches, blunted cannulas and/or syringes, and single-dose applicator swabs REF: Page 94 TRUE/FALSE 1. The over-the-counter product Anbesol with benzocaine can be safely used by all family members. ANS: F Correct: Anbesol comes in a variety of strengths. One concentration cannot be used safely by all family members. REF: Page 97, Table 6-2 2. Although topical anesthetics are generally regarded as safe, if used improperly they can produce adverse reactions that are fatal. ANS: T REF: Pages 100, 102 and Box 6-2 3. A patient presents to your dental office the day after her dental appointment, complaining of swelling and itching on the right side of her face. You should reassure the patient that it is not possible that her symptoms are related to dental anesthesia. ANS: F Correct: Some allergic reactions occur up to 2 days after the anesthetic is given. REF: Page 102 4. Benzocaine topical anesthetic exists almost entirely in its base form, making absorption into circulation high. ANS: F Correct: Benzocaine topical anesthetic exists almost entirely in its base form, making absorption into circulation low. REF: Page 97 5. The published maximum dosage recommendation for the topical anesthetic benzocaine is 200 mg. ANS: F Correct: The published maximum dosage recommendations for benzocaine have not been established and do not exist. REF: Page 97 6. Lidocaine is metabolized in the liver and excreted via the kidneys with less than 10% remaining unchanged. ANS: T REF: Page 98 7. The most commonly found form of lidocaine is in base form because it is water soluble and can easily penetrate and be absorbed into the tissues. ANS: F Correct: The base form is poorly soluble in water and has poor penetration and absorption abilities. REF: Page 98 8. Tetracaine hydrochloride has a rather slow onset of action; however, it can last approximately 45 minutes. ANS: T REF: Page 98 MULTIPLE CHOICE 1. What is the name of a common ester topical anesthetic? a. Lidocaine b. Dyclonine hydrochloride c. Prilocaine 2.5% d. Benzocaine ANS: D Benzocaine is the name of a common ester topical anesthetic. REF: Page 91 2. What is the name of a common ketone topical anesthetic? a. Lidocaine b. Dyclonine hydrochloride c. Tetracaine hydrochloride d. Benzocaine ANS: B Dyclonine hydrochloride is the name of a common ketone topical anesthetic. REF: Page 91 3. What is the name of the most potent ester topical anesthetic? a. 2.5% Lidocaine and 2.5% prilocaine cream b. Dyclonine hydrochloride c. Tetracaine hydrochloride d. Benzocaine ANS: C Tetracaine hydrochloride is the name of the most potent ester topical anesthetic. REF: Page 91 4. Which of the following are considered advantages for the use of topical anesthetic agents? 1. Pain control 2. Stimulation of gag reflex 3. Can be purchased over the counter 4. Ease of use a. 1, 4 b. 1, 3, 4 c. 1, 2, 3, 4 d. Some other combination ANS: A Pain control and ease of use are two advantages for the use of topical anesthetic agents. Topical anesthetic agents can be used to reduce the patient’s gag reflex. The fact that topical anesthetic agents can be purchased over the counter is not necessarily an advantage when one considers the risk of toxicity. REF: Page 92 5. Which of the following characteristics could contribute to the properties of an ideal intraoral topical anesthetic? a. Allergenic b. Allow pain-free application c. Dissolves readily at the site of application d. Produces some systemic toxicity ANS: B Ideal properties of an intraoral topical anesthetic would include the pain-free application of the agent. REF: Page 93 6. What is the main difference in the mechanism of action between topical anesthetics and injectable anesthetics? a. Location of the blocking of nerve conduction b. Increase of depolarization c. Decrease of excitability threshold d. All of the above ANS: A Topical anesthetics work by blocking nerve conduction at the surface of the skin or mucous membrane. REF: Page 93 7. To obtain the most benefit from the use of topical anesthetics, a fairly substantial amount of topical should be placed on the cotton tip applicator. This amount mixes with the saliva and may numb the tongue, soft palate, or pharynx. a. Both statements are true. b. Both statements are false. c. The first statement is true; the second statement is false. d. The first statement is false; the second statement is true. ANS: D Only a small amount of the gel or ointment on the applicator tip is necessary to achieve the desired results. An excess amount mixes with the saliva and may numb the tongue, soft palate, or pharynx, which usually leads to patient dissatisfaction of the whole process. REF: Page 94 8. Which of the following properties are advantages to topical anesthetics being in a liquid form? a. Provides anesthesia to a widespread area b. Useful to decrease a patient’s gag reflex c. Can be applied to site-specific areas with an applicator d. All of the above e. Some combination of the above ANS: D Liquids are great for providing anesthesia to a widespread area. They are especially useful when trying to decrease a patient’s gag reflex, and the use of a liquid for a more site-specific procedure requires an applicator. REF: Page 94 9. Which of the following properties is an advantage of purchasing a single-dose unit of a topical anesthetic? a. Dose manageable b. Cost-effective c. Less cross-contamination d. a and c e. All of the above ANS: D Individual packaging of topical anesthetic is not only less messy; it also helps to prevent possible cross-contamination and allows monitoring of the dosage being used. REF: Page 95 10. What is a drawback to the use of an unmetered topical anesthetic spray? a. Cost b. Not dose manageable c. Cross-contamination d. Site-specific ANS: B Unmetered sprays are not recommended because they do not allow the operator control of the amount of anesthetic dispensed. REF: Page 95 11. Which topical anesthetic has warnings about the risk of methemoglobinemia? a. Benzocaine creams b. Benzocaine sprays c. Tetracaine hydrochloride d. Dyclonine hydrochloride ANS: B Warnings have been issued about the possibility of benzocaine sprays causing methemoglobinemia. REF: Page 95 12. Which of the following are considered advantages of the application of dental topical anesthetics in a patch form? a. Site-specific b. Multiple choices c. Cost-effective d. All of the above ANS: A The advantage of patches over other methods of administration in that they can be placed directly to desired sites. Patches available for intraoral topical anesthesia are limited. REF: Page 95 13. Which of the following is/are true regarding topical anesthetics? a. Allergic reactions can occur up to 2 days after the anesthetic is given. b. Benzocaine and tetracaine are both amides, which increases their potential for causing an allergic reaction. c. If there were an allergic reaction, it is likely to present immediately at the time of anesthesia. d. All of the above e. Some combination of the above ANS: A Allergic reactions can occur up to 2 days after the anesthetic is given. REF: Page 94 14. Possible localized adverse effects of topical anesthetics could include which of the following? 1. Stinging at the site of application 2. Tissue discoloration 3. Sloughing a. 1, 2 b. 2, 3 c. 2, 3 d. 1, 2, 3 e. Some other combination ANS: D Possible localized adverse effects of topical anesthetics could include stinging at the site of application, tissue discoloration and sloughing. REF: Page 102 15. What is the reason that concentrations of topical anesthetic agents are higher than those of their injectable counterparts? a. Topical agents are not natural vasoconstrictors like injectable anesthetic agents. b. They facilitate high plasma concentrations of topical anesthetic agents. c. They facilitate diffusion of the topical anesthetic agent through the mucous membranes. d. With topical anesthetic agents, systemic absorption decreases. ANS: C The reason that concentrations of topical anesthetic agents are higher than that of their injectable counterparts is to facilitate diffusion of the topical anesthetic agent through the mucous membranes. REF: Page 100 16. Which patients may be more susceptible to adverse effects to topical anesthetic agents? a. Children b. Elderly c. Medically compromised d. All of the above ANS: D Children, elderly, and medically compromised individuals are more susceptible to the adverse reactions to topical anesthetics. REF: Page 100 17. Why does the local and systemic absorption of topical anesthetics increase the risk of toxicity? a. Topical anesthetics do not contain vasoconstrictors. b. Topical anesthetics are formulated in high concentrations. c. Topical anesthetics are absorbed quickly into the tissue and blood stream due to vasodilation of the area. d. All of the above ANS: D With the higher concentrations of the topical anesthesia and in the absence of vasoconstricting abilities, the risk of local and systemic absorption increases with the use of topical anesthetics. REF: Page 100 18. What is the available concentration of Oraqix? a. 5% lidocaine and 5% prilocaine b. 2.5% lidocaine and 2.5% prilocaine c. 14% Benzocaine, 2% butamben, and 2% tetracaine hydrochloride d. 20% Benzocaine and 5% lidocaine ANS: B Oraqix is available for dental use in a 2.5% lidocaine and 2.5% prilocaine concentration. REF: Page 100 19. What is the maximum recommended dose of Oraqix at one dental treatment session? a. Two cartridges b. Four cartridges c. Five cartridges d. Eleven cartridges ANS: C The maximum recommended dose of Oraqix at one dental treatment session is five cartridges. REF: Page 100 20. What FDA Category does Oraqix fall into? a. Category A b. Category B c. Category C d. Categories B or C, depending on the concentration used. ANS: B Oraqix falls into FDA Category B. REF: Page 100 21. While at room temperature, Oraqix is in gel form in the cartridge. It will liquidate as it reaches body temperature in the periodontal pocket. a. Both statements are true. b. Both statements are false. c. The first statement is true; the second statement is false. d. The first statement is false; the second statement is true. ANS: B While at room temperature, Oraqix is in liquid form in the cartridge. It will gel as it reaches body temperature in the periodontal pocket. REF: Page 100 22. What has the combined lidocaine/prilocaine cream been approved and effectively used for? a. Medical procedures b. Dental procedures c. Topical anesthetic for skin abrasions d. All of the above ANS: A The combined lidocaine/prilocaine cream been approved and effectively used for medical procedures. REF: Page 99 23. Which of the following are best practices to follow when administering local anesthesia of any kind in the dental office? 1. Review the patient’s health and dental history at all appointments. 2. Use the lowest concentration of anesthesia to satisfy clinical requirements. 3. Limit the area of application. 4. Know the concentration of the drug being used. a. 2, 3, 4 b. 1, 3 c. Some other combination d. All of the above ANS: D Best practices to follow when administering local anesthesia of any kind in the dental office include: Review the patient’s health and dental history at all appointments; use the lowest concentration of anesthesia to satisfy clinical requirements; limit the area of application; and know the concentration of the drug being used. REF: Pages 96, 102 and Box 6-3