Pharma TUFT Flashcards
Which of the following is a local anesthetic subject to inactivation by
plasma esterases?
a. Procaine
b. Lidocaine
c. Prilocaine
d. Mepivacaine
e. Bupivacaine
(a) Proccaine is the only ester listed – all the rest are amides
- Procaine differs from lidocaine in that
a. Procaine is a p-aminobenzoic acid ester and lidocaine is not
b. Lidocaine is a meta-aminobenzoic acid ester and procaine is not
c. The duration of action of procaine is longer than that of an equal
total dose of lidocaine
d. Procaine hydrochloride is metabolized into diethylaminoethanol
and benzoic acid.
(a) this is basically a true-false type question. (a) is the only
statement that is true
- Which of the following local anesthetics would be expected to produce
a sensitization reaction in a patient allergic to lidocaine?
a. Mepivacaine
b. Tetracaine
c. Procaine
d. Prilocaine
e. Dibucaine
i. (a), (b) and (c)
ii. (a), (d) and (e)
iii. (b) and (c) only
iv. (b), (c) and (d)
v. (b), (d) and (e)
(ii) another ester vs. amide type identification question.
Lidoccaine is an amide, thus other amides will be crossallergenic
- mepivacaine, prilocaine and dibucaine are the other
amides listed. Procaine and tetracaine are esters and will not be
cross-allergenic
- The hydrolysis of procaine occurs mainly in the
a. Liver
b. Lungs
c. Plasma
d. Muscles
e. Kidneys
(c) procaine is an ester; esters are metabolized predominately
by pseudocholinesterases in the plasma.
- Which of the following is local anesthetic subject to inactivation by
plasma esterases?
a. Lidocaine
b. Prilocaine
c. Tetracaine
d. Mepivacaine
e. Bupivacaine
(c) esters are metabolized by plasma esterases - tetracaine is
the only ester listed, all the rest are amides
- The activity of procaine is terminated by
a. Elimination by the kidney
b. Storage in adipose tissue
c. Metabolism in the liver only
d. Metabolism in the liver and by pseudocholinesterase in the
plasma
(d) remember #9 above? see the word “mainly”? same
question, but worded a little differently to throw you off. Again,
procaine is an ester; esters are metabolized predominately by
pseudocholinesterases in the plasma, but also to some extent
by esters in the liver.
- All of the following factors are significant determinants of the duration
of conduction block with amide-type local anesthetics EXCEPT the
a. pH of tissues in the area of injection
b. Degree of vasodilatation caused by the local anesthetic
c. Blood plasma cholinesterase levels
d. Blood flow through the area of conduction block
e. Concentration of the injected anesthetic solution
(c) the word “EXCEPT” should alert you that this is basically a
true-false type question with 4 true statements and 1 false
statement; you just have to figure out which one! In this case,
you just have to remember that plasma cholinesterase levels
are only important for the duration of action of ester-type LAs,
not amides, which are metabolized in the liver. All the other
statements are variables which affect duration of the block, but
apply to both esters and amides.
- Which of the following is contraindicated for a patient who had an
allergic reaction to procaine six months ago?
a. Nerve block with lidocaine
b. Topical application of lidocaine
c. Topical application of tetracaine
d. Infiltration with an antihistamine
(c) again, just another question that requires you to be able to
pick out an ester or an amide from a list. Since procaine is an
ester, only another ester LA would be cross-allergenic. In this
list the only ester listed is tetracaine
- Bupivacaine (Marcaine ) has all of the following properties relative to
lidocaine (Xylocaine ) EXCEPT bupivacaine
a. Is more toxic
b. Is an ester-type local anesthetic
c. Has a slower onset of action
d. Has a longer duration of action
(d) According to textbooks, local anesthetics fall into the
following classes in terms of duration of action: short: procaine;
moderate: prilocaine, mepivacaine, lidocaine; long: bupivacaine,
tetracaine, etidocaine.
Statements (a), 3, and 4 would be true if
the question was comparing mepivacaine to bupivacaine, which
are structurally similar; but the comparison is to lidocaine. The
only difference that applies is duration of action ((d)),
bupivacaine is longer. (b) is wrong, both are amides.
- Amide-type local anesthetics are metabolized in the
a. Serum
b. Liver
c. Spleen
d. Kidney
e. Axoplasm
(b) don’t forget: esters in plasma; amides in liver
- The duration of action of lidocaine would be increased in the presence
of which of the following medications?
a. Prazosin
b. Propranolol
c. Hydrochlorothiazide
d. Lisinopril
e. Digoxin
(b) this is an interaction I tested you on several times – now you
know why! Propranolol interacts with lidocaine in two ways.
By slowing down the heart via beta receptor blockade, blood
delivery (and lidocaine) to the liver is reduced, thus lidocaine
remains in the systemic circulation longer, and can potentially
accumulate to toxic levels. Propranolol and lidocaine also
compete for the same enzyme in the liver, thus metabolism of
lidocaine can be reduced
- Severe liver disease least affects the biotransformation of which of
the following?
a. Lidocaine
b. Procaine
c. Prilocaine
d. Mepivacaine
(b) Answer is (b)- You should be able to recognize that all of
these drugs are local anesthetics. Local anesthetics are of one
of two types, either esters or amides. Ester types are subject to
hydrolysis in the plasma and thus have short half lives. Amides
are metabolized primarily in the liver and have longer half lives.
Thus the biotransformation (e.g., metabolism; again, the rats are
using a different word to confuse you, even though they are
asking the same basic question) of an amide type local
anesthetic would be the most altered in the presence of sever
liver disease. The key word here is “least”. Of the drugs listed,
only procaine is an ester. The rest are amides.
- A patient has been given a large volume of a certain local anesthetic
solution and subsequently develops cyanosis with
methemoglobinemia. Which of the following drugs most likely was
administered?
a. Procaine
b. Prilocaine
c. Dibucaine
d. Lidocaine
e. Mepivacaine
(b) strictly memorization
- Use of prilocaine carries the risk of which of the following adverse
effects?
a. Porphyria
b. Renal toxicity
c. Gastric bleeding
d. Methemoglobinemia
(d) same as above but asked backwards. Methemoglobinemia
may result from a toluidine metabolite of prilocaine,
orthotoluidine
- The most probable cause for a serious toxic reaction to a local
anesthetic is
a. Psychogenic
b. Deterioration of the anesthetic agent
c. Hypersensitivity to the vasoconstrictor
d. Hypersensitivity to the local anesthetic
e. Excessive blood level of the local anesthetic
(e) Most toxic reactions of a serious nature are related to
excessive blood levels arising from inadvertent intravascular
injection. Hypersensitivity reactions (options b & c) are rare, but
excessive blood levels will induce toxic reactions like CNS
stimulation in most everyone. This is a case where option (e) is
the “best” answer, because it is more likely than the other
alternatives, which might be true, but are not as likely (e.g,
“most probable”) to happen.
- High plasma levels of local anesthetics may cause
a. Inhibition of peristalsis
b. stimulation of baroreceptors resulting in severe hypotension
c. Inhibition of the vagus nerve to the heart
d. Depression of inhibitory neurons in the CNS
(d) Initially LAs inhibit central inhibitory neurons, which results in
CNS stimulation, which can proceed to convulsions. At higher
doses, they inhibit both inhibitory and excitatory neurons,
leading to a generalized state of CNS depression which can
result in respiratory depression and death.
20a. Unfortunately, you injected your lidocaine intra-arterially. The first
sign of lidocaine toxicity that might be seen in the patient would be
a. Elevated pulse rate
b. Sweating
c. CNS excitation
d. Cardiovascular collapse
e. CNS depression
(c) same question as above just worded differently. The intraarterial
injection would result in the high plasma levels
mentioned in the previous question
- The first sign that your patient may be experiencing toxicity from too
much epinephrine would be
a. Cardiovascular collapse
b. Convulsions
c. Elevated pulse rate
d. Slurred speech
(c) it is a sympathomimetic after all. All the
- Which disease condition would make the patient most sensitive to the
epinephrine in the local anesthetic?
a. Grave’s disease
b. Diabetes
c. HIV
d. Alcoholism
e. Schizophrenia
(a) Grave’s disease is an autoimmune disease that causes
hyperthyroidism – the resulting high levels of circulating thyroid
hormone result in a hypermetabolic state with heightened
sympathetic activity, which combined with injected epinephrine
could result in a hypertensive crisis.
- Cardiovascular collapse elicited by a high circulating dose of a local
anesthetic may be caused by
a. Syncope
b. Vagal stimulation
c. Histamine release
d. Myocardial depression
e. Medullary stimulation
(d) Cardiovascular collapse is due to a direct action of the local
anesthetic on the heart muscle itself (LA’s in toxic doses
depress membrane excitability and conduction velocity), thus
(d) is the correct answer. All of the other alternatives are indirect
ways to affect the heart
- The most serious consequence of systemic local anesthetic toxicity is
a. Vertigo
b. Hypertension
c. Hyperventilation
d. Post depressive central nervous system convulsions
e. Postconvulsive central nervous system depression
(e) Of the options listed, this is the one that will kill the patient,
which I guess makes it the most serious
- Hypotensive shock may result from excessive blood levels of each of
the following local anesthetics EXCEPT
a. Cocaine
b. Procaine
c. Lidocaine
d. Tetracaine
e. Mepivacaine
(a) All the listed local anesthetics except cocaine are
vasodilators, especially ester-ctype drugs such as proccaine
and the amide lidocaine. Cocaine is the only local anesthetic
that predictably produces vasoconstriction. Cocaine is also the
only local anesthetic to block the reuptake of NE into adrenergic
neurons, and thus potentiate the NE that has been released
from nerve endings
- Which of the following anesthetic drugs produces powerful
stimulation of the cerebral cortex?
a. Cocaine
b. Procaine
c. Lidocaine
d. Tetracaine
e. Mepivacaine
(a) see explanation above
- Local anesthetics block nerve conduction by
a. Depolarizing the nerve membrane to neutrality
b. Increasing membrane permeability to K+
c. Increasing membrane permeability to Na+
d. Preventing an increase in membrane permeability to K+
e. Preventing an increase in membrane permeability to Na+
(e) Na+ ions are involved, which limits your choices to
(c) and (e). (c) would increase or facilitate nervous impulse
conduction, which is the opposite of what you want the local
anesthetic to do, so pick (e).
- Which of the following is true regarding the mechanism of action of
local anesthetics?
a. Usually maintain the nerve membrane in a state of
hyperpolarization
b. Prevent the generation of a nerve action potential
c. Maintain the nerve membrane in a state of depolarization
d. Prevent increased permeability of the nerve membrane to
potassium ions
e. Interfere with intracellular nerve metabolism
(b) this should be really obvious
- Local anesthetic agents prevent the generation of nerve impulses by
a. Decreasing threshold for stimulation
b. Decreasing resting membrane potential
c. Decreasing inward movement of sodium ion
d. Increasing inward movement of potassium ion
c) Answer is (c)- straight memorization- nerve impulses are
generated by the influx of sodium resulting in depolarization.
repolarization and inactivity occurs when potassium moves out.
(sodium-potassium pump). LAs act by blocking Na+ movement.
- Local anesthetics interfere with the transport of which of the following
ions during drug-receptor interaction
a. Sodium
b. Calcium
c. Chloride
d. Potassium
e. Magnesium
(a) see how many different ways they can ask the same
question?
- If the pH of an area is lower than normal body pH, the membrane
theory of local anesthetic action predicts that the local anesthetic
activity would be
a. Greater, owing to an increase in the free-base form of the drug
b. Greater, owing to an increase in the cationic form of the drug
c. Less, owing to an increase in the free-base form of the drug
d. Less, owing to a decrease in the free-base form of the drug
e. None of the above
(d) the next three or four questions are all versions of the same
thing – see the explanation below
- A local anesthetic injected into an inflamed area will NOT give
maximum effects because
a. The pH of inflamed tissue inhibits the release of the free base
b. The drug will not be absorbed as rapidly because of the
decreased blood supply
c. The chemical mediators of inflammation will present a chemical
antagonism to the anesthetic
d. Prostaglandins stabilize the nerve membrane and diminish the
effectiveness of the local anesthetic
(a) while some of the other alternatives sound plausible, think
about the factoids you were taught about local anesthetics and
variables that affect their action. An important one was the role
of pH and ionization factors. Remember, the free base or
nonionized form is the form that passes through membranes,
yet once inside the neuron only the ionized form is effective.
Inflamed tissue has a lower pH than normal tissue and will shift
the equilibrium of the LA solution such that most of it remains
ionized and thus unavailable to penetrate
- The penetration of a local anesthetic into nervous tissue is a function
of the
a. Length of the central alkyl chain
b. Lipid solubility of the ionized form
c. Lipid solubility of the unionized form
d. Ester linkage between the aromatic nucleus and the alkyl chain
e. Amide linkage between the aromatic nucleus and the alkyl
(c) Lipid solubility of the unionized form
- At a pH of 7.8, lidocaine (pKa = 7.8) will exist in
a. the ionized form
b. the nonionized form
c. an equal mixture of ionized and nonionized forms
d. a mixture 10 times more ionized than nonionized forms
c. an equal mixture of ionized and nonionized forms
The more rapid onset of action of local anesthetics in small nerves is
due to
a. The slightly lower pH of small nerves
b. The greater surface-volume ratio of small nerves
c. The increased rate of penetration resulting from depolarization
d. Smaller nerves usually having a higher threshold
probably the answer is (b) - the theory
goes that there is a size dependent critical length of
anesthetic exposure necessary to block a given nerve.
- Which of the following statements are true regarding onset, degree
and duration of action of local anesthetics?
a. The greater the drug concentration, the faster the onset and the
greater the degree of effect
b. Local anesthetics block only myelinated nerve fibers at the nodes
of Ranvier
c. The larger the diameter of the nerve fiber, the faster the onset of
effect
d. The faster the penetrance of the drug, the faster the onset of
effect
i. (a), (b), and (c)
ii. (a), (b) and (d)
iii. (a) and (c) only
iv. (b), (c) and (d)
(ii) if you knew the fact above about small nerves, then this
question basically becomes a true false type thing, and (c) is the
false statement.
- A dentist administers 1.8 ml of a 2% solution of lidocaine. How many
mg of lidocaine did the patient receive?
a. 3.6
b. 9
c. 18
d. 36
e. 180
(d) 2% solution = 20 mg/ml X 1.8 ml = 36 mg lidocaine. And
you thought you would never have to do this stuff again!
- Three ml of a local anesthetic solution consisting of 2% lidocaine with
1:100,000 epinephrine contains how many milligrams of each?
a. 6 mg. lidocaine, 0.3 mg. epinephrine
b. 6 mg. lidocaine, 0.03 mg. epinephrine
c. 60 mg. lidocaine 0.3 mg. epinephrine
d. 60 mg. lidocaine 0.03 mg epinephrine
e. 600 mg lidocaine, 0.3 mg. epinephrine
f. 600 mg. lidocaine, 0.03 mg. epinephrine
(d) 2% lidocaine = 20 mg/ml x 3 = 60 mg lidocaine
1:100,000 epi = 0.01 mg/ml x 3 = 0.03 mg epi
- The maximum allowable adult dose of mepivacaine is 300 mg. How
many milliliters of 2% mepivacaine should be injected to attain the
maximal dosage in an adult patient?
a. 5
b. 10
c. 15
d. 20
e. 25
(c) 2% mepivacaine = 20 mg/ml, so 300 mg / 20 mg/ml = 15 ml
- A recently introduced local anesthetic agent is claimed by the
manufacturer to be several times as potent as procaine. The product
is available in 0.05% buffered aqueous solution in 1.8 ml. cartridge.
The maximum amount recommended for dental anesthesia over a 4-
hour period is 30 mg. The amount is contained in approximately how
many cartridges?
a. 1-9
b. 10-18
c. 19-27
d. 28-36
e. Greater than 36
d. 28-36
- According to AHA guidelines, the maximum # of carpules of
local anesthetic containing 1:200,000 epinephrine that can be used
in the patient with cardiovascular disease is
a. 1
b. 2
c. 3
d. 4
e. 11
(d) the AHA limit is 0.04 mg, compared to 0.2 mg in the healthy
patient. 1:200,000 equals 0.005 mg/ml or 0.009 per 1.8 ml
carpule. 4 carpules would thus contain 0.036 mg, which is just
below the 0.04 mg limit
For treating most oral infections, penicillin V is preferred to penicillin G
because penicillin V
a. Is less allergenic
b. Is less sensitive to acid degradation
c. Has a greater gram-negative spectrum
d. Has a longer duration of action
e. Is bactericidal, whereas penicillin G is not
(b) memorization: basically the only difference
- The sole therapeutic advantage of penicillin V over penicillin G is
a. Greater resistance to penicillinase
b. Broader antibacterial spectrum
c. More reliable oral absorption
d. Slower renal excretion
e. None of the above
(c) reworded version of the above
- Which of the following penicillins is administered ONLY by deep
intramuscular injection?
a. Ampicillin
b. Dicloxacillin sodium
c. Penicillin G procaine
d. Penicillin V potassium
c. Penicillin G procaine
8 The principal difference among potassium, procaine and benzathine
salts of penicillin G is their
a. Potency
b. Toxicity
c. Duration of action
d. Antibacterial spectrum
e. Diffusion into the cerebrospinal fluid
c. Duration of action
- Which of the following antibiotics is cross-allergenic with penicillin
and should NOT be administered to the penicillin-sensitive patient?
a. Ampicillin
b. Erythromycin
c. Clindamycin
d. Lincomycin
e. Tetracycline
(a) ampicillin sort of sounds like penicillin so it must be the
answer
- Which of the following antibiotics may be cross-allergenic with
penicillin?
a. Neomycin
b. Cephalexin
c. Clindamycin
d. Erythromycin
e. All of the above
b. Cephalexin
- Which of the following antibiotics shows an incidence of
approximately 8% cross-allergenicity with penicillins?
a. neomycin
b. cephalexin
c. bacitracin
d. vancomycin
e. tetracycline
b. cephalexin
- Which of the following groups of antibiotics is related both structurally
and by mode of action to the penicillins?
a. Polymyxins
b. Cycloserines
c. Cephalosporins
d. Chloramphenicols
c. Cephalosporins
- For the dentist, the most reliable method of detecting a patient’s allergy to penicillin is by
a. Injecting penicillin intradermally
b. Taking a thorough medical history
c. Placing a drop of penicillin on the eye
d. Having the patient inhale a penicillin aerosol
e. Injecting a small amount of penicillin intravenously
b. Taking a thorough medical history
- Which of the following antibiotics is the substitute of choice for
penicillin in the penicillin-sensitive patient?
a. Bacitracin
b. Erythromycin
c. Tetracycline
d. Chloramphenicol
b. Erythromycin
- Most anaphylactic reactions to penicillin occur
a. When the drug is administered orally
b. In patients who have already experienced an allergic reaction to
the drug
c. In patients with a negative skin test to penicillin allergy
d. When the drug is administered parenterally
e. Within minutes after drug administration
i. (a), (b) and (d)
ii. (b), (c) and (d)
iii. (b), (d) and (e)
iv. (b) and (e) only
v. (c), (d) and (e)
iii. (b), (d) and (e)
- Which of the following penicillins has a broader gram-negative
spectrum than penicillin G?
a. Nafcillin
b. Ampicillin
c. Cephalexin
d. Methicillin
e. Penicillin V
b. Ampicillin
- Which of the following penicillins has the best gram-negative
spectrum?
a. Nafcillin
b. Ampicillin
c. Methicillin
d. Penicillin V
e. Phenethicillin
b. Ampicillin
- Which of the following antibiotics should be considered the drug of
choice in the treatment of infection caused by a penicillinaseproducing
staphylococcus?
a. Neomycin
b. Ampicillin
c. Tetracycline
d. Penicillin V
e. Dicloxacillin
e. Dicloxacillin
- Oral infections caused by organisms that produce penicillinase
should be treated with
a. Ampicillin
b. Dicloxacillin
c. Erythromycin
d. Any of the above
e. Only (a) or (c) above
b. Dicloxacillin
- Which of the following antibiotics is LEAST effective against
penicillinase-producing microorganisms?
a. Ampicillin
b. Cephalexin
c. Methicillin
d. Clindamycin
e. Erythromycin
a. Ampicillin
- Which of the following is a bactericidal antibiotic used specifically in
the treatment of infections caused by Pseudomonas species and
indole-positive Proteus species?
a. Ampicillin
b. Penicillin V
c. Tetracycline
d. Dicloxacillin
e. Carbenicillin
e. Carbenicillin
- Penicillin’s effectiveness against rapidly growing cells is primarily due
to its effect on
a. Protein synthesis
b. Cell wall synthesis
c. Nucleic acid synthesis
d. Chelation of metal ions
e. Cell membrane permeability
b. Cell wall synthesis
- Chlortetracycline acts by interfering with
a. Cell wall synthesis
b. Nuclear acid synthesis
c. Protein synthesis on bacterial but not mammalian ribosomes
d. Protein synthesis on mammalian but not bacterial ribosomes
c. Protein synthesis on bacterial but not mammalian ribosomes
- The probable mechanism of the bacteriostatic action of sulfonamides
involves
a. Disruption of the cell membrane
b. Coagulation of intracellular proteins
c. Reduction in oxygen utilization by the cells
d. Inhibition of metabolism by binding acetyl groups
e. Competition with para-aminobenzoic acid in folic acid synthesis
e. Competition with para-aminobenzoic acid in folic acid synthesis
- The sulfonamides act by
a. Suppressing bacterial protein synthesis
b. Inhibiting the formation of the cytoplasmic bacterial membrane
c. Inducing the formation of “lethal” bacterial proteins
d. Inducing a deficiency of folic acid by competition with paraaminobenzoic
acid
d. Inducing a deficiency of folic acid by competition with paraaminobenzoic
acid
