random pharm Ch 9-13
5. Which benzodiazepine is preferred for use in elderly patients? a. Diazepam b. Lorazepam c. Midazolam d. Clonazepam
ANS: b Benzodiazepines such as lorazepam, oxazepam, and temazepam do not require phase I metabolism to become inactivated in the body. The efficiency of phase I drug metabolism can sometimes be compromised in elderly adults. Phase II drug metabolism (conjugation) is less affected by age than phase I drug metabolism. REF: pp. 138-139
17. Which of the following local anesthetics is safest to use for dental treatment for a pregnant woman? a. Mepivacaine b. Lidocaine c. Articaine d. Bupivacaine
ANS: b Both lidocaine and prilocaine are in the U.S. Food and Drug Administration pregnancy category B, whereas mepivacaine, articaine, and bupivacaine are category C drugs. If a local anesthetic is needed, lidocaine in the smallest effective dose should be used. REF: p. 117
4. Repolarization of a nerve occurs by: a. Influx of potassium b. Influx of sodium c. Efflux of potassium d. Efflux of calcium e. None of the above
ANS: a Correct: During depolarization, an inward flux of sodium into the nerve occurs. During repolarization, an inward flux of potassium into the nerve occurs. The activation, but not the repolarization, of a nerve involves a slow calcium influx. REF: p. 114
18. Which inhalational agent has a pungent smell and can cause respiratory acidosis with deeper levels of anesthesia? a. Isoflurane b. Halothane c. Enflurane d. Sevoflurane e. Nitrous oxide
ANS: a Correct: Of the agents listed, only isoflurane is irritating and causes significant respiratory acidosis. Incorrect choices: Halothane, enflurane, sevoflurane, and nitrous oxide are not associated with respiratory acidosis or excessive irritation. REF: p. 133
20. For which intravenous anesthetic is porphyria a contraindication? a. Thiopental b. Propofol c. Ketamine d. Fentanyl e. Droperidol
ANS: a Correct: Porphyria is a contraindication for all barbiturates, including thiopental, because they stimulate the synthesis of porphyrins. Incorrect choices: The other choices do not stimulate the synthesis of porphyrins and are not contraindicated in porphyria. REF: p. 134
17. Approximately 15% of halothane is metabolized in the liver, and these metabolites have been suggested as a cause of renal damage. a. Both parts of the statement are true. b. Both parts of the statement are false. c. The first part of the statement is true, the second part is false. d. The first part of the statement is false, the second part is true.
ANS: a Correct: Approximately 15% of halothane is metabolized in the liver, and these metabolites have been suggested as a cause of liver damage. Although halothane has proved to be a reliable and effective general anesthetic for many years, the occurrence of this adverse effect has diminished its popularity. REF: p. 133
22. Chronic use of barbiturates can lead to: a. Both physical and psychologic dependence b. Physical but not psychologic dependence c. Psychologic but not physical dependence d. Neither physical nor psychologic dependence
ANS: a Chronic use of barbiturates can lead to both physical and psychologic dependence. Long-term use produces a state similar to alcohol intoxication. The barbiturate addict becomes progressively depressed and is unable to function. Tolerance develops to most effects of barbiturates but not to the lethal dose. REF: p. 143
32. Which of the following agents is known to inhibit nonproductive cough? a. Benzonatate (Tessalon Perles) b. Bupivacaine (Marcaine) c. Diphenhydramine (Benadryl) d. Benzocaine (Anbesol, Orabase B)
ANS: a Correct: Benzonatate is a tetracaine congener, indicated in the management of nonproductive cough. Incorrect choices: The other agents are not indicated for treatment of nonproductive cough. REF: p. 120
50. Levonordefrin is more potent than epinephrine.
ANS: False Levonordefrin has one-fifth the pressor potency of epinephrine. REF: p. 122
43. The rate of local anesthetic absorption is increased by the presence of local inflammation.
ANS: False Local inflammation causes a decrease in the pH of the tissue extracellular fluid and drives more of the local anesthetic into the ionized form, which is less able to penetrate nerves. REF: p. 114
28. Meperidine is used for its antiemetic properties during recovery from surgery.
ANS: False Meperidine is given for its analgesic actions. It has emetic, not antiemetic, properties as a side effect. REF: p. 230
25. Nitrous oxide is a complete anesthetic.
ANS: False Nitrous oxide cannot produce complete anesthesia alone. REF: p. 131
24. The more soluble the anesthetic is in body tissues, the more rapid the onset and recovery will be.
ANS: False The less soluble the anesthetic is in body tissues, the more rapid the onset and recovery will be. REF: p. 129
27. Patients should be instructed to fast before a dental procedure using nitrous oxide.
ANS: False The patient should eat a light meal before the appointment but should be warned to avoid eating a large meal within 3 hours of the appointment. REF: p. 132
48. No justification exists for the use of epinephrine in a concentration greater than 1:200,000, except in cases in which hemostasis is needed.
ANS: True REF: p. 121
49. A patient can produce endogenous epinephrine far in excess of that administered in dentistry in the presence of inadequate anesthesia.
ANS: True REF: p. 121
46. For lengthy dental procedures, bupivacaine is recommended over lidocaine because bupivacaine has a longer duration of action.
ANS: True Bupivacaine is the longest lasting of the local anesthetics used in dentistry. REF: pp. 119
26. To prevent diffusion hypoxia, patients should be given 100% oxygen for 5 minutes after treatment with nitrous oxide.
ANS: True Diffusion hypoxia may result because of the rapid outward flow of nitrous oxide accompanied by oxygen and carbon dioxide. The loss of carbon dioxide, a stimulant to respiratory drive, could decrease ventilation with resultant hypoxia. REF: p. 131
47. The recommended dose of epinephrine to combine with a local anesthetic is 1:200,000 for most procedures.
ANS: True Epinephrine 1:100,000 and 1:200,000 have been shown to produce about the same amount of vasoconstriction. A 1:50,000 dose is used in cases in which local hemostasis is needed. REF: p. 121
45. Patients who are allergic to procaine are not likely to display cross-hypersensitivity to lidocaine.
ANS: True Procaine is an ester of PABA. Ester local anesthetics have a much greater allergic potential than amides. Lidocaine is an amide. Allergy to lidocaine is unlikely, and cross-hypersensitivity with procaine is even less likely because of the disparate chemical structures. REF: p. 118
44. Use of skin testing to determine local anesthetic allergies is unreliable.
ANS: True Skin testing is unreliable because it can give both false-positive and false-negative results. REF: p. 117
15. Which of the following agents may decrease the effectiveness of benzodiazepines? a. Tobacco b. Omeprazole c. Valproic acid d. Fluoxetine
ANS: a Correct: Smoking tobacco reduces the effectiveness of the benzodiazepines by stimulating the hepatic microsomal enzymes in the liver, which increases its rate of metabolism. A higher dose of a benzodiazepine would then be required to produce the same effect. Incorrect choices: Omeprazole can inhibit the metabolism of benzodiazepines. Valproic acid may displace diazepam from binding sites, increasing free circulating levels. Fluoxetine can increase diazepam blood levels by altering its clearance from the body. REF: p. 140
2. Which portion of the chemical structure of a typical local anesthetic is considered lipophilic (lipid soluble)? a. Aromatic nucleus b. Amino group c. Both a and b d. Neither a nor b
ANS: a Correct: The aromatic nucleus of the local anesthetic contains no positive or negative charges. This feature allows it to mix with and pass through lipid environments, such the plasma membrane of a nerve cell. Incorrect choices: The amino group is considered water soluble or hydrophilic. At certain pHs, it can gain a charge, which will enhance its solubility in water and prohibit its solubility in lipids. REF: p. 113
13. The therapeutic index of benzodiazepines is __________ that of the barbiturates. a. Wider than b. Narrower than c. The same as d. None of the above
ANS: a Correct: The difference between the effective and toxic doses of the benzodiazepines is greater than that observed for the barbiturates. Thus one is less susceptible to overdose with benzodiazepines as compared with barbiturates. REF: p. 140
37. Which agent has the greater proportion of -adrenergic activity to -adrenergic activity? a. Levonordefrin b. Epinephrine c. Neither—they have equivalent proportions.
ANS: a Correct: The ratio of levonordefrin is 75/25, whereas the ratio is 50/50 for epinephrine. REF: p. 122
19. Which of the following agents used for dental anxiety has a fast onset and short half-life? a. Triazolam b. Diazepam c. Lorazepam d. Alprazolam
ANS: a Correct: Triazolam has a fast onset and short half-life. Incorrect choices: Diazepam has a very fast onset but long half-life. Lorazepam and Alprazolam have immediate onset but relatively short half-lives. REF: p. 142
3. Which benzodiazepine would be most suitable for intramuscular administration? a. Midazolam b. Diazepam c. Alprazolam d. Flurazepam
ANS: a For benzodiazepines other than midazolam, the intramuscular route gives slow, erratic, and unpredictable results. REF: p. 138
6. In the presence of an acidic environment, such as infection or inflammation, the amount of free base is reduced; therefore __________ of the local anesthetic is in the ionized form, making anesthesia __________ difficult. a. More, more b. More, less c. Less, more d. Less, less
ANS: a In an acidic environment, more of the local anesthetic is in the ionized form, making anesthesia more difficult. Other reasons include dilution by fluid, inflammation, and vasodilation in the area. REF: pp. 114-115
10. Local anesthetics cross: a. The placenta and blood-brain barrier b. The placenta but not the blood-brain barrier c. The blood-brain barrier but not the placenta d. Neither the placenta nor the blood-brain barrier
ANS: a Local anesthetics cross the placenta and blood-brain barrier. REF: p. 115
2. Nitrous oxide, as used in the dental office, maintains the patient in stage: a. I b. II c. III d. IV
ANS: a Nitrous oxide maintains the patient in stage I. Stage I analgesia is characterized by the development of analgesia or reduced sensation to pain. The patient is conscious and can still respond to commands. Reflexes are present, and respiration remains regular. Some amnesia may also be present. REF: p. 128
29. Approximately __________% of articaine is metabolized by the liver. a. 5 to 10 b. 20 to 25 c. 50 to 75 d. 90
ANS: a Only 5% to 10% of articaine is metabolized by the liver; the other 90% to 95% is metabolized in the blood. Its major metabolite is articainic acid, and the extent of activity of this metabolite is unclear. REF: pp. 119-120
9. Addition of vasoconstrictor to local anesthetic (1) reduces blood supply to the area, (2) increases blood supply to the area, (3) limits systemic absorption, (4) increases systemic absorption, (5) reduces systemic toxicity, (6) increases systemic toxicity. Which of the three pairs of choices is correct? a. 1, 3, 5 b. 1, 4, 5 c. 2, 3, 5 d. 2, 3, 6 e. 2, 4, 6
ANS: a The vasoconstrictor reduces the blood supply to the area, limits systemic absorption, and reduces systemic toxicity. When a local anesthetic solution does not contain a vasoconstrictor, the anesthetic drug is more quickly removed from the injection site and distributed into systemic circulation than if the solution contained a vasoconstrictor. Plain anesthetics will exhibit a shorter duration of action and result in a more rapid buildup of a systemic blood level. Therefore any anesthetic given without a vasoconstrictor is more likely to be toxic than those given with a vasoconstrictor. REF: p. 115
33. The vasoconstrictors are members of the autonomic nervous system drugs called the: a. Adrenergic agonists b. Adrenergic antagonists c. Cholinergic agonists d. Cholinergic antagonists
ANS: a Vasoconstrictors are called adrenergic agonists or sympathomimetics. REF: p. 120
38. A cardiac patient can be given __________ cartridges of 1:100,000 epinephrine without exceeding the cardiac dose. a. 0.5 b. 2.0 c. 4.0 d. 6.0
ANS: b A cardiac patient can be given 2.0 cartridges of 1:100,000 epinephrine without exceeding the cardiac dose. REF: p. 122
6. Which of the following intravenous general anesthetic agents can be administered intramuscularly? a. Methohexital (Brevital) b. Ketamine (Ketalar) c. Diazepam (Valium) d. Propofol (Diprivan)
ANS: b Although most injectable general anesthetics are administered intravenously, one agent, ketamine, can also be given intramuscularly. REF: p. 130
9. At the termination of a N2O/O2 sedation procedure, the patient should be placed on 100% oxygen for at least __________ minutes. a. 2 b. 5 c. 8 d. 11
ANS: b At the termination of a N2O/O2 sedation procedure, the patient should be placed on 100% oxygen for at least 5 minutes. If the mask is removed without the oxygen recovery period and the patient is allowed to breathe room air, a phenomenon known as diffusion hypoxia may result. REF: p. 131
41. Which of the following agents is the most common topical local anesthetic? a. Lidocaine b. Benzocaine c. Tetracaine d. Dyclonine
ANS: b Benzocaine, an ester, is the most commonly used topical anesthetic; lidocaine, an amide, is the second most commonly used. REF: p. 123
19. Recovery from a single intravenous dose of thiopental (sodium pentothal) is the result of: a. Drug excretion b. Drug redistribution c. Drug metabolism d. Enzyme induction
ANS: b Correct: After entering the bloodstream, thiopental rapidly goes to the brain, redistributes to lean tissues (muscles with high vascularity), and finally moves to the fat. Incorrect choices: Drug excretion and metabolism occur with thiopental, but they are preceded by drug redistribution. Enzyme induction is a long-term action of barbiturates and is not responsible for termination of a single dose of thiopental. REF: p. 134
7. The cationic form of a local anesthetic is needed to penetrate the nerve membrane, and the free base form exerts blocking action by binding to the specific receptor site. a. Both parts of the statement are true. b. Both parts of the statements are false. c. The first part of the statement is true, the second part is false. d. The first part of the statement is false, the second part is true.
ANS: b Correct: Although the free base form of a local anesthetic is needed to penetrate the nerve membrane, the cationic form exerts blocking action by binding to the specific receptor site. REF: p. 115
11. Amide local anesthetics are metabolized: a. By being hydrolyzed by plasma pseudocholinesterases b. Primarily by the liver c. In the spleen d. Minimally and are excreted virtually unchanged
ANS: b Correct: Amide local anesthetics are metabolized primarily by the liver. In severe liver disease, or with alcoholism, amides may accumulate and produce systemic toxicity. Incorrect choices: Esters are hydrolyzed by plasma pseudocholinesterases and liver esterases. Procaine is hydrolyzed to para-aminobenzoic acid (PABA), a metabolite that may be responsible for its allergic reactions. REF: p. 115
28. Which of the following local anesthetic agents is both an ester and an amide? a. Benzonatate b. Articaine c. Bupivacaine d. Dyclonine
ANS: b Correct: Articaine differs from other amide local anesthetics because it also has an ester linkage. Incorrect choices: Benzonatate is an ester, bupivacaine is an amide, and dyclonine is neither an ester nor an amide. REF: p. 119
31. Which local anesthetic agent is neither an ester nor an amide? a. Propoxycaine b. Dyclonine c. Articaine d. Benzonatate
ANS: b Correct: Dyclonine is a topical local anesthetic that is neither an ester nor an amide. Incorrect choices: Propoxycaine and benzonatate are ester local anesthetics, and articaine has both amide and ester bonds. REF: p. 120
20. Epinephrine is combined with local anesthetics so as to: a. Enhance absorption b. Prolong duration c. Delay onset d. Increase potency
ANS: b Correct: Epinephrine restricts the diffusion of the local anesthetic away from the site of injection and thus allows the local anesthetic to stay at the site longer, producing a longer duration of action. Incorrect choices: Epinephrine does not enhance absorption, delay onset, or increase the potency of the local anesthetic agent with which it is combined. REF: p. 117
1. The following are characteristics of the ideal local anesthetic except: a. Sterilization by autoclave b. Slow onset c. Reversible d. Absence of local reactions
ANS: b Correct: For dentistry, a local anesthetic with a relatively rapid onset of action is desired so that the time between administration of the anesthetic and the commencement of a dental procedure can be minimized. Incorrect choices: Dental local anesthetic solutions are not sterilized by autoclave before use. Reversibility of the actions of the agent is necessary so that the patient can regain normal sensation in the tissue. Local reactions such as irritation are considered untoward and undesirable. REF: pp. 112-113
4. Nitrous oxide has: a. Rapid onset and high solubility in blood b. Rapid onset and low solubility in blood c. Rapid onset and low minimal alveolar concentration (MAC) d. Slow onset and high MAC
ANS: b Correct: General anesthetics with low solubility in blood have a rapid onset. Incorrect choices: High solubility in blood often retards onset of action. Nitrous oxide has rapid onset and high MAC, unlike the other choices. REF: pp. 129-130
22. Which of the following effects is not a characteristic of ketamine action? a. Produces a "dissociative" anesthesia b. Produces significant bronchoconstriction c. Increases cardiac output d. Recovery associated with delirium and hallucinations
ANS: b Correct: Ketamine does not cause bronchoconstriction; it is actually a potent bronchodilator. Incorrect choices: Ketamine does produce a dissociative anesthesia, increases cardiac output, and can cause delirium and hallucinations. REF: pp. 134-135
7. Nitrous oxide combined with a halogenated inhalational anesthetic (N2O/O2): a. Increases the MAC b. Decreases the MAC c. Typically precipitates a toxic reaction d. Inhibits the metabolism of the halogenated anesthetic
ANS: b Correct: N2O/O2 is given throughout most surgical procedures that necessitate the use of general anesthesia because it reduces the concentration of other agents needed to obtain the desired depth of anesthesia. Incorrect choices: Nitrous oxide does not increase the MAC of halogenated anesthetics. Nitrous oxide is commonly given with halogenated anesthetics without fear of toxic reactions. Nitrous oxide has no influence on the metabolism of halogenated anesthetics, many of which are sparingly metabolized. REF: pp. 130-131
30. __________ is an ester local anesthetic. a. Prilocaine (Citanest) b. Tetracaine (Pontocaine) c. Bupivacaine (Marcaine) d. Lidocaine (Xylocaine)
ANS: b Correct: The chemical structure of tetracaine contains an ester linkage. The other agents listed contain amide linkages. REF: p. 120
5. The following states are characteristics of the salt form of a local anesthetic except one. Which one is the exception? a. Charged, cation (ionized) b. Alkaline c. Crystalline solid d. Stable
ANS: b Correct: The salt form of a local anesthetic is a form that has a positive charge and is complexed with an acid, such as hydrochloric acid, in the dose form. The positive charge is the result of the addition of a hydrogen ion to the molecule, making it an acid, not an alkaline base. The salt form more readily crystallizes, which creates a stable complex. REF: pp. 114-115
15. Nitrous oxide is contraindicated for use in a patient with which of the following conditions? a. Diabetes b. Emphysema c. Hypertension d. Glaucoma e. None of the above
ANS: b Correct: Use of nitrous oxide is contraindicated in patients with any type of upper respiratory or pulmonary obstruction. Incorrect choices: Diabetes and glaucoma are not contraindications to nitrous oxide administration. Nitrous oxide causes vasodilation, thus it does not exacerbate hypertension. REF: p. 132
18. Which of the following benzodiazepines is the drug of choice for treatment of repetitive, intractable seizures that require IV therapy? a. Chlordiazepoxide (Librium) b. Diazepam (Valium) c. Zolpidem (Ambien) d. Eszopiclone (Lunesta)
ANS: b Diazepam (Valium) or lorazepam (Ativan) is the drug of choice for treatment of repetitive, intractable seizures (status epilepticus) that require IV therapy; they also are used for treatment of seizures caused by local anesthetic toxicity. Orally administered diazepam is of little value, even as a maintenance anticonvulsant. Oral clonazepam is used as an adjunct to other anticonvulsants for some difficult-to-control types of seizures. REF: p. 141
10. Diffusion hypoxia may occur if insufficient 100% oxygen is delivered at the termination of a nitrous oxide procedure because: a. The lungs are insufficiently inflated. b. The loss of carbon dioxide could decrease ventilation. c. The nitrous oxide is highly soluble in blood. d. Nitrous oxide has a slow onset and recovery.
ANS: b Diffusion hypoxia occurs because of the rapid outward flow of nitrous oxide accompanied by oxygen and carbon dioxide. The loss of carbon dioxide, a stimulant to the respiratory drive, could decrease ventilation with resultant hypoxia. Patients may complain of headaches or other side effects if this occurs. REF: p. 131
19. Which of the following components of a local anesthetic agent may produce a hypersensitivity reaction that exhibits itself as an acute asthmatic attack? a. The vasoconstrictor b. The antioxidant for the vasoconstrictor c. The sodium hydroxide d. The sodium chloride
ANS: b Local anesthetics with vasoconstrictors also contain a sulfite that serves as an antioxidant. In sulfite-sensitive patients, the sulfites may produce a hypersensitivity reaction that exhibits itself as an acute asthmatic attack. This reaction is the same as the "salad bar" syndrome, a hypersensitivity reaction to sulfites. REF: p. 117
14. Nitrous oxide cylinders are __________ and oxygen cylinders are __________ (1) red, (2) green, (3) blue, (4) orange, (5) tan a. 1, 2 b. 3, 2 c. 2, 4 d. 3, 4 e. 3, 5
ANS: b Nitrous oxide cylinders are blue, and oxygen cylinders are green. The cylinders are also "pin coded" to prevent inadvertent mixing of cylinders and lines. REF: p. 132
34. Plain anesthetics without vasoconstrictor will exhibit a __________ duration of action and result in a __________ buildup of a systemic blood level. a. Shorter, less-rapid b. Shorter, more-rapid c. Longer, less-rapid d. Longer, more-rapid
ANS: b Plain anesthetics will exhibit a shorter duration of action and result in a more-rapid buildup of a systemic blood level. Therefore any anesthetic given without a vasoconstrictor is more likely to be toxic than those given with a vasoconstrictor. Any advantage gained by eliminating the vasoconstrictor must be weighed against the potential for adverse effects from the epinephrine. REF: p. 121
21. Although a lethal dose of barbiturates can only be approximated, severe poisoning will follow the ingestion of __________ times the hypnotic dose. a. 5 b. 10 c. 15 d. 20
ANS: b Severe poisoning will follow the ingestion of 10 times the hypnotic dose of barbiturates, and life is seriously threatened when more than 15 times the hypnotic dose is consumed. The cause of death is respiratory failure when an overdose occurs. The treatment includes conservative management and treatment of specific symptoms. REF: p. 143
9. Benzodiazepines are indicated for epilepsy because they: a. Reduce the electrical activity in the seizure focus b. Limit the spread of abnormal activity to other parts of the brain c. None of the above d. All of the above
ANS: b The benzodiazepines prevent the spread of abnormal electrical activity to tissues surrounding the anatomic seizure focus (when such a focus exists) but have little effect on the discharges at the focus itself. REF: p. 139
42. Which of the following local anesthetics may be combined for injection-free local anesthesia? a. Articaine and bupivacaine b. Lidocaine and prilocaine c. Benzocaine and tetracaine d. Lidocaine and articaine
ANS: b The combination of lidocaine and prilocaine gel (Oraqix) applied into the periodontal pocket offers pain relief during scaling and root planing procedures. This combination, in gel form, provides a duration of action of approximately 20 minutes. The onset of action is approximately 30 seconds after application. REF: p. 124 TRUE/FALSE
36. The maximal safe dose of epinephrine for the cardiac patient is __________ mg. a. 0.02 b. 0.04 c. 0.2 d. 0.4
ANS: b The maximal safe dose of epinephrine for the cardiac patient is 0.04 mg. For the healthy patient, the maximal safe dose is 0.2 mg. REF: p. 122
24. Several cases of methemoglobinemia have been reported after the use of: a. Lidocaine b. Mepivacaine c. Prilocaine d. Articaine
ANS: c Although the toxicity of prilocaine is 60% of that occurring with lidocaine, several cases of methemoglobinemia have been reported after its use. Prilocaine is metabolized to orthotoluidine and, in large doses, can induce some methemoglobinemia. Although the small doses required in dental practice are not likely to present a problem in healthy, nonpregnant adults, prilocaine should not be administered to patients with any condition in which problems of oxygenation may be especially critical. REF: p. 119
40. Which of the following dental local anesthetics are available without vasoconstrictor? (1) mepivacaine, (2) prilocaine, (3) lidocaine, (4) bupivacaine a. 1, 2, 3, 4 b. 1, 2, 3 c. 1, 2 d. 3, 4
ANS: c Because mepivacaine and prilocaine have less vasodilating effect, they can be used without vasoconstrictor. In contrast, lidocaine and bupivacaine produce too much vasodilation to be used without a vasoconstrictor. REF: p. 123
7. Benzodiazepines enhance or facilitate the action of the neurotransmitter: a. Acetylcholine b. Epinephrine c. γ-Aminobutyric acid (GABA) d. Serotonin
ANS: c Benzodiazepines enhance or facilitate the action of the neurotransmitter GABA, a major inhibitory transmitter in the central nervous system (CNS). It acts in the limbic, thalamic, cortical, and hypothalamic levels of the CNS. Benzodiazepines act as agonists at the benzodiazepine receptor site, thereby reducing the symptoms of anxiety. REF: p. 139
8. The clinical effects of benzodiazepines in humans are __________ at lower doses. a. Drowsiness and sleep b. Drowsiness and anxiety reduction c. Anxiety reduction and panic reduction d. Anxiety reduction and sleep
ANS: c The clinical effects of benzodiazepines in humans are anxiety and panic reduction at lower doses and production of drowsiness and sleep at higher doses. Repeated doses of benzodiazepines reduce rapid-eye-movement sleep. Usual doses produce a marked reduction in stages 3 and 4 sleep (deep sleep), which, after long-term use, can interfere with restorative sleep. REF: p. 139
18. Which of the following agents may be used as an alternative if a patient reports a history of allergies to all local anesthetic agents? a. Chloral hydrate b. Thiothixene (Navane) c. Diphenhydramine (Benadryl) d. Hydrocortisone (Cortaid)
ANS: c Correct: Antihistamines, because of their similarity in structure to local anesthetics, have some local anesthetic action. Diphenhydramine (Benadryl) in a concentration of 1% plus 1:100,000 epinephrine is recommended to be given by injection to produce a block. No prepared product is available, thus this combination must be prepared from its constituents. Incorrect choices: Chloral hydrate is used for preoperative sedation. Thiothixene is an antipsychotic. Hydrocortisone is used to reduce inflammation. REF: p. 117
27. Which local anesthetic agent is derived from thiophene? a. Tetracaine b. Bupivacaine c. Articaine d. Propoxycaine
ANS: c Correct: Articaine is unique from the other amide and ester local anesthetics in that it is derived from thiophene. Incorrect choices: Tetracaine and propoxycaine are esters of PABA. Bupivacaine is an amide of xylidine. REF: p. 119
20. Barbiturates act on nerves by enhancing the binding of which neurotransmitter to its receptor? a. Glutamate b. Serotonin c. GABA d. Chloride
ANS: c Correct: Barbiturates produce their effect by enhancing GABA receptor binding. They prolong the opening of the GABA receptor-associated chloride channels. Incorrect choices: Barbiturates do not affect the binding of glutamate or serotonin to their receptors. Chloride is not a neurotransmitter. REF: p. 142
22. Which of the following statements is true of mepivacaine? a. Cross-allergenicity has been demonstrated between mepivacaine and other currently available amides. b. Mepivacaine is effective topically. c. Mepivacaine can be used as a 3% solution without a vasoconstrictor. d. The benefit of a shorter duration of anesthesia warrants eliminating the vasoconstrictor.
ANS: c Correct: Because mepivacaine produces less vasodilation than lidocaine, it can be used as a 3% solution without a vasoconstrictor. It can be used for short procedures when a vasoconstrictor is contraindicated. Caution should be exercised when using the increased concentrations of the local anesthetic without a vasoconstrictor because systemic toxicity is more likely. Incorrect choices: No cross-allergenicity between the amide mepivacaine, other currently available amides, or the esters has been documented. Mepivacaine is not effective topically; however, it is used for infiltration, block, spinal, epidural, and caudal anesthesia. Except in unusual cases, the benefit of a shorter duration does not warrant eliminating the vasoconstrictor, especially when the concentration of the drug is increased. REF: p. 119
17. The following habits should be followed to minimize insomnia except for one. Which one is the exception? a. Light snack (warm milk) at bedtime b. Awake at 6 AM even if sleep only began at 5 AM c. Exercise within 3 hours of bedtime d. Remaining in bed no longer than 20 minutes without sleeping e. No smoking within 8 hours of bedtime
ANS: c Correct: Exercise during the day, but not within 3 hours of bedtime. Incorrect choices: Light snack is calming. Regular awakening is important to establish a routine. Extended time in bed without sleep alters the psychologic purpose of being in bed—to sleep. Smoking may reduce calmness needed for sleeping. REF: p. 141
14. __________ may be used to reverse some of the effects of a benzodiazepine. a. Ramelteon (Rozerem) b. Phenobarbital (Luminal) c. Flumazenil (Romazicon) d. Carisoprodol (Soma)
ANS: c Correct: Flumazenil (Romazicon), a benzodiazepine antagonist available for IV administration, may be used to reverse some of the effects of a benzodiazepine. It has been shown to reverse the sedating and psychomotor effects, but reversing the respiratory depression produced by the benzodiazepines is incomplete. The amnesia is not consistently reversed. Incorrect choices: Ramelteon (Rozerem) is a melatonin receptor agonist. Phenobarbital (Luminal) is a barbiturate. Carisoprodol (Soma) is a centrally acting skeletal muscle relaxant. REF: p. 140
23. Levonordefrin is commonly combined with which local anesthetic? a. Lidocaine b. Procaine c. Mepivacaine d. Bupivacaine
ANS: c Correct: Mepivacaine is the only local anesthetic listed that is available in combination with levonordefrin. Incorrect choices: Lidocaine and bupivacaine are available with epinephrine, not levonordefrin. Procaine is an ester local anesthetic that is not used in dentistry today. REF: p. 119
1. Antianxiety agents are most commonly orally administered because the effective dose of a particular antianxiety agent is very predictable. a. Both parts of the statement are true. b. Both parts of the statement are false. c. The first part of the statement is true, the second part is false. d. The first part of the statement is false, the second part is true.
ANS: c Correct: Orally administered drugs are most commonly used to provide relaxation for the anxious patient because intravenous (IV) dosing requires more training and experience than most general dentists possess. However, the dose of a particular antianxiety agent effective for a particular patient is vastly variable, involving both intrapatient and interpatient variation. REF: p. 137
3. The loss of respiratory control (i.e., diminished carbon dioxide response, paralysis of intercostal muscles) first occurs during which stage of anesthesia? a. Stage I b. Stage II c. Stage III d. Stage IV
ANS: c Correct: Paralysis of intercostal muscles begins in plane III and is complete in plane IV of stage III anesthesia. REF: p. 129
6. Some benzodiazepines are transformed in the body to active metabolites. The active metabolites are formed by phase II drug metabolism. 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: c Correct: Phase I drug metabolism transforms some benzodiazepines to active metabolites. REF: p. 138
12. Procaine (Novocaine) is metabolized primarily by the: a. Liver b. Lungs c. Plasma d. Kidneys
ANS: c Correct: Procaine is an ester local anesthetic and is metabolized primarily by plasma pseudocholinesterase. Incorrect choices: Amide local anesthetics rely on cytochrome P450 mixed-function oxidases. These enzymes are found mainly in the liver, but they can be found in other tissues, such as the kidney and lungs. REF: p. 115
15. The maximal safe dose of lidocaine 2% with 1:100,000 epinephrine is approximately __________ cartridges. a. 3 b. 6.5 c. 8.5 d. 11.5
ANS: c The maximal safe dose of lidocaine 2% with 1:100,000 epinephrine or 1:200,000 epinephrine is approximately 8.5 cartridges. For lidocaine 2% with 1:50000 epinephrine, the maximum is approximately 5.5 cartridges. REF: p. 116
12. The best indicator of the degree of sedation under nitrous oxide is: a. Response to a painful stimulus b. Percent nitrous oxide being delivered c. Response to questions d. Muscle tone e. Eye movements
ANS: c Correct: The best indicator of the degree of sedation is the patient's response to questions. Perform repeated evaluations throughout the dental procedure. Incorrect choices: Response to a painful stimulus should only be evaluated after one is confident that adequate sedation has been achieved. The percentage nitrous oxide is a poor indicator of degree of sedation. Muscular relaxation in response to nitrous oxide cannot be demonstrated in most patients. Eye movements are not predictive of adequate sedation by nitrous oxide. REF: p. 132
13. The greatest danger in using nitrous oxide for analgesia is: a. Hyperventilation b. A gas embolus c. Oxygen deprivation d. Cardiac arrhythmias e. Foreign body aspiration
ANS: c Correct: The potency of nitrous oxide is low, facilitating a high percentage of the gas to be inhaled. If not careful, oxygen delivery to the patient could be too low. Incorrect choices: Respiration is usually within normal limits, gas emboli are produced by injection directly into the circulation, and nitrous oxide is not arrhythmiagenic; nitrous oxide does not significantly increase nor decrease gag reflex. REF: p. 132
1. According to Guedel's description of the stages and planes of anesthesia, the induction period refers to: a. Stage I b. Stage II c. Stages I and II d. Stages I, II, and III e. None of the above
ANS: c Correct: The term induction refers to the quick change in the patient's state of consciousness from stage I up to stage III. Incorrect choices: Induction includes both stage I and stage II but not stage III, the point at which surgical anesthesia is attained. REF: p. 128
23. Neuroleptanalgesia is achieved by which combination of agents? a. Fentanyl and promethazine b. Fentanyl and ketamine c. Fentanyl and droperidol d. Fentanyl and nitrous oxide e. Fentanyl, droperidol, and nitrous oxide
ANS: c Correct: The term neuroleptanalgesia refers to the so-called wakeful anesthetic state produced by the combination of a neuroleptic drug, droperidol, and a potent opioid analgesic, fentanyl. Droperidol produces marked sedation and a catatonic state. The combination of drugs is marketed as Innovar and is usually given intravenously for a rapid onset. Incorrect choices: Fentanyl and promethazine, fentanyl and ketamine, and fentanyl and nitrous oxide do not contain a neuroleptic. The combination of fentanyl, droperidol, and nitrous oxide is one that results in neuroleptanalgesia. REF: p. 135 TRUE/FALSE
21. Lidocaine with epinephrine 1:100,000 provides a __________ duration of pulpal anesthesia. a. 30-minute b. 30- to 60-minute c. 60- to 90-minute d. 90-minute or more
ANS: c Lidocaine with epinephrine 1:100,000 provides a 1.0- to 1.5-hour duration of pulpal anesthesia. Soft-tissue anesthesia is maintained for 3 to 4 hours. Lidocaine with epinephrine 1:50,000 is used for hemostasis during surgical procedures. REF: p. 119
11. Which of the following parenteral benzodiazepines seems to have the greatest likelihood to produce amnesia? a. Diazepam (Valium) b. Midazolam (Versed) c. Triazolam (Halcion) d. Eszopiclone (Lunesta)
ANS: c Oral triazolam seems to have a greater likelihood to produce amnesia than other oral benzodiazepines. Clinical use has produced episodes of amnesia that can sometimes last several hours and can occur with several benzodiazepines. Patients should be warned not to sign important papers or make important decisions after benzodiazepines are administered. REF: p. 139
35. Patients with uncontrolled high blood pressure, hyperthyroidism, angina pectoris, and cardiac arrhythmias and those who have had a myocardial infarction or cerebrovascular accident in the past __________ should make an appointment for elective dental treatment after their medical condition is under control. a. 6 weeks b. 3 months c. 6 months d. 12 months
ANS: c Patients with any of the preceding conditions in the past 6 months should make an appointment for elective dental treatment after their medical condition is under control. For patients who have had a myocardial infarction or cerebrovascular accident, the time span would be 6 months after the cardiovascular or cerebrovascular event. REF: p. 122
5. Which of the following general anesthetic agents has the largest MAC value? a. Halothane b. Isoflurane c. Nitrous oxide d. Enflurane
ANS: c The MAC of nitrous oxide is greater than 100. Halothane has a MAC of 0.75, isoflurane of 1.15, and enflurane of 1.68. MAC is defined as the minimal alveolar concentration of an anesthetic at 1 atmosphere required to prevent 50% of patients from responding to a supramaximal surgical stimulus. REF: p. 130
10. When benzodiazepines are used in dentistry to produce conscious sedation, the appearance of __________ is used as an initial endpoint for the dose administered. a. Flushed skin b. Miosis c. Ptosis d. Rapid eye movement
ANS: c The appearance of ptosis is used as an initial endpoint for the dose administered. When benzodiazepines are used in dentistry to produce conscious sedation, this side effect of CNS depression is used as the primary effect. The amount of the benzodiazepine used to provide conscious sedation is titrated to the patient's response. REF: p. 139
8. The average percentage of nitrous oxide required for patient comfort is: a. 10% b. 25% c. 35% d. 50%
ANS: c The average percentage of nitrous oxide required for patient comfort is 35%. The percentage of nitrous oxide required for patient comfort is variable and may range from 10% to 50%. REF: p. 131
16. The benzodiazepines are preferable to the barbiturates as hypnotics because the risk of physical addiction or serious poisoning is much less. The efficacy of the benzodiazepines in the treatment of chronic insomnia has been demonstrated for longer than 2 years. 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: c The benzodiazepines are preferable to the barbiturates as hypnotics because the risk of physical addiction or serious poisoning is much less. However, the efficacy of the benzodiazepines in the treatment of chronic insomnia has not been demonstrated past 1 month. REF: p. 141
2. Which of the following agents are the most commonly prescribed antianxiety drugs? a. Nonbenzodiazepine-nonbarbiturate sedative-hypnotics b. Nonbenzodiazepine-nonbarbiturate receptor agonists c. Benzodiazepines d. Barbiturates
ANS: c The benzodiazepines are the most commonly prescribed antianxiety drugs. The members of this group differ mainly in their onset and duration of action, dose, and dose forms available. REF: p. 137
8. Reducing the rate of systemic absorption of a local anesthetic is important when it is used in dentistry because: a. Otherwise, too large an area would be anesthetized. b. If not, the anesthesia would not last long enough to complete a dental procedure. c. The chance of systemic toxicity is reduced. d. Local anesthesia is associated with respiratory depression.
ANS: c With reduced absorption, the chance of systemic toxicity is reduced. A vasoconstrictor is often added to the local anesthetic to reduce the rate of absorption. REF: p. 115
39. Which two agents are known to cause clinically significant drug interactions when combined with epinephrine? a. Selective serotonin reuptake inhibitors and -adrenergic antagonists b. -Adrenergic antagonists and phenothiazines c. Tricyclic antidepressants and monoamine oxidase inhibitors d. -Adrenergic antagonists and tricyclic antidepressants e. Benzodiazepines and monoamine oxidase inhibitors
ANS: d Correct: -Adrenergic antagonists cause hypertension followed by reflex bradycardia when combined with epinephrine, and tricyclic antidepressants may cause an exaggerated increase in pressor response. Incorrect choices: Monoamine oxidase inhibitors and phenothiazines can interact with epinephrine, but the results are usually not clinically significant. Benzodiazepines do not significantly interact with epinephrine. REF: p. 122
16. Which of the following agents are the most common agents precipitating malignant hyperthermia? (1) halothane, (2) lidocaine, (3) mepivacaine, (4) succinylcholine a. 1, 2, 3, 4 b. 2, 3, 4 c. 2, 3 d. 1, 4
ANS: d Correct: Halothane, the inhalation anesthetic, and succinylcholine, the neuromuscular blocking agent, are the most common agents precipitating malignant hyperthermia. Incorrect choices: In the past, the belief was that the amide local anesthetics might precipitate malignant hyperthermia, but they are currently no longer implicated. Patients with a family history of malignant hyperthermia can be given amide local anesthetic agents. REF: p. 117
13. Which of the following local anesthetic agents have the potential to cause methemoglobinemia as an adverse effect? a. Prilocaine and lidocaine b. Lidocaine and mepivacaine c. Prilocaine and mepivacaine d. Prilocaine and articaine e. Mepivacaine and articaine
ANS: d Correct: Prilocaine (by virtue of its orthotoluidine metabolite) and articaine have been demonstrated to produce methemoglobinemia when administered in high doses. Incorrect choices: No reports have been documented of lidocaine or mepivacaine producing methemoglobinemia. REF: p. 115
14. Which nerve function is the most sensitive to inhibition by local anesthetic agents? a. Touch b. Warmth c. Pressure d. Autonomic e. Pain
ANS: d Correct: Sensitivity to inhibition by local anesthetics is a function of nerve diameter and myelination. Postganglionic autonomic nerves are of small diameter and unmyelinated. Incorrect choices: The correct order of sensitivity is autonomic, warmth, pain, touch, and pressure. REF: p. 116
4. Once a benzodiazepine is absorbed, the rate at which it reaches its site of action is dependent on: a. Lipid solubility b. Protein binding c. Ionization d. All of the above e. None of the above
ANS: d Once a benzodiazepine is absorbed, the rate at which it crosses into the cerebrospinal fluid through the blood-brain barrier is dependent on protein binding, lipid solubility, and the ionization constant of the compound. REF: p. 138
25. Prilocaine plain has a duration of action slightly __________ than mepivacaine plain, and prilocaine with epinephrine has a duration of action slightly __________ than lidocaine with epinephrine. a. Shorter, shorter b. Shorter, longer c. Longer, shorter d. Longer, longer
ANS: d Prilocaine plain has a duration of action slightly longer than mepivacaine plain, and prilocaine with epinephrine has a duration of action slightly longer than lidocaine with epinephrine. Prilocaine's niche in dentistry involves situations in which the desired duration of action is somewhat longer than that obtained with mepivacaine either with or without a vasoconstrictor. REF: p. 119
26. Which of the following local anesthetics has the longest duration of action? a. Lidocaine b. Mepivacaine c. Prilocaine d. Bupivacaine
ANS: d The major advantage of bupivacaine is its greatly prolonged duration of action. It is indicated in lengthy dental procedures when pulpal anesthesia of greater than 1.5 hours is needed or when postoperative pain is expected. Compared with lidocaine with epinephrine, the onset of bupivacaine with epinephrine is slightly longer, but the duration is at least twice that of lidocaine. REF: p. 119
11. A patient for whom nitrous oxide is to be administered should be warned to avoid eating a large meal within __________ hours of the appointment. a. 2 b. 3 c. 4 d. 5
ANS: d The patient should eat a light meal before the appointment but should be warned to avoid eating a large meal within 3 hours of the appointment. REF: p. 132
16. Nitrous oxide has been shown to reduce the activity of methionine synthetase, the enzyme involved with the function of which vitamin? a. Vitamin B1 b. Vitamin K c. Vitamin B6 d. Folic Acid e. Vitamin B12
ANS: e Chronic nitrous oxide abuse can produce a neuropathy that is thought to be caused by the inhibition of this enzyme and its effect on the utilization of vitamin B12. REF: p. 133
3. The mechanism of local anesthetics involves action on: a. Myelinated nerve b. Axons c. Sodium channels d. Both a and c e. Both b and c
ANS: e Correct: Local anesthetics bind to sodium channels found in the axons of nerves. They stop the propagation of the electrical impulse along the axon. Incorrect choices: Local anesthetics' primary mode of action does not include myelinated nerve. REF: pp. 114-115
12. Which of the following statements is true concerning administration of benzodiazepines and pregnancy? a. An increased risk of congenital malformation in infants of mothers taking benzodiazepines in the second trimester has been reported. b. Most of the benzodiazepines are classified as U.S. Food and Drug Administration (FDA) category D drugs; triazolam and temazepam are in FDA category X. c. Near-term administration of benzodiazepines to the mother has resulted in floppy infant syndrome. d. Both a and b are true. e. Both b and c are true.
ANS: e Correct: Most of the benzodiazepines are classified as FDA category D drugs; triazolam and temazepam are in FDA category X. Near-term administration of benzodiazepines to the mother has resulted in floppy infant syndrome. Incorrect choices: An increased risk of congenital malformation in infants of mothers taking benzodiazepines in the first trimester has been reported. Because these agents are seldom absolutely needed (except for epilepsy), they should be avoided in women who are or may become pregnant and in nursing mothers. The first trimester, often before the patient knows that she is pregnant, is the time benzodiazepines are more likely to be teratogenic or cause problems in the fetus. REF: p. 140
21. The following are characteristics of propofol except for one. Which one is the exception? a. Rapid onset of action b. Potent vasodilator c. Undergoes phase II metabolism in the liver d. Intravenous anesthetic e. Structurally related to barbiturates
ANS: e Correct: Propofol is an agent that is unrelated to any other general anesthetic. Incorrect choices: Propofol is ultrashort acting, vasodilating, conjugated in the liver, and administered intravenously. REF: p. 134
