Review Questions

Question 1

Select the INCORRECT statement regarding the regulation of pharmacologically active chemicals in the United States.

A.Manufacturers of saw palmetto cannot claim their product will cure benign prostatic hyperplasia.

B.Some prescription-only drug formulations are available in lower strengths as OTC products.

C.Herbal medications cannot be sold to the public until their safety has been evaluated by the FDA.

D.It is possible for prescription-only drugs to be moved into OTC status after reevaluation by the FDA.

E.Advertising claims of herbal medication manufacturers are monitored by the Federal Trade Commission (FTC).

Answer 1

C

Question 2

Which of the following statements concerning the Controlled Substances Act of 1970 is INCORRECT?

A.Schedule I drugs can only be used for research purposes and may not be prescribed.

B.Prescriptions for schedule II drugs may not be refilled.

C.Prescriptions for schedule III and IV drugs may be telephoned to a pharmacist.

D.Prescriptions for schedule III and IV drugs can be refilled 5 times within 6 months.

E.Dentists are required to register with the DEA (Drug Enforcement Administration) in order to prescribe controlled substances.

F.Use of Schedule IV drugs has a greater potential for abuse than use of Schedule II drugs.

G.Schedule V drugs can be obtained without a prescription in certain states.

Answer 2

F

Question 3

The principal difference between the general category of prescription drugs and the subcategory of prescription controlled substances is that ALL controlled substances:

A.Cannot be refilled

B.Have no accepted medical use

C.Are administered parenterally

D.Must undergo FDA evaluation for safety and efficacy

E.Have a much greater potential to produce psychologic dependence

Answer 3

E

Question 4

A patient with a history of episodic attacks of coughing, wheezing, and shortness of breath is being evaluated in the asthma clinic. Several drug treatments with different routes of administration are under consideration. Which of the following statements about routes of administration is MOST correct?

A.Blood levels rise more slowly after intramuscular injection than after oral dosing

B.Administration of anti-asthmatic drugs by inhaled aerosol is usually associated with less adverse effects than is administration of these drugs by mouth

C.Bioavailability of most drugs is greater with rectal (suppository) administration than with sublingual administration

D.Administration of a drug by transdermal patch is often faster in onset than oral administration but is associated with more first pass metabolism

Answer 4

B

Question 5

A city clinic is considering the substitution of generic drugs in order to save money. The clinical pharmacologist is asked to advise them on the bioavailability of generic products. She informs the head of the clinic that the bioavailability of drugs is:

A.Established by FDA regulation at 100% for preparations for intramuscular injection

B.100% for oral preparations that are not metabolized in the liver

C.Calculated from the peak concentration of drug divided by the dose administered

D.Important because bioavailability determines the fraction of the administered dose that reaches the systemic circulation

E.Equal to 1 (100%) only for drugs administered by a parenteral route

Answer 5

D

Question 6

A 30-year-old patient with status epilepticus is placed on phenytoin in the emergency room. In order to achieve therapeutic concentrations rapidly, a loading dose is used. The loading dose should be equal to which of the following?

A.4.5 times the half-life of the drug

B.The amount of drug in the body divided by the plasma concentration

C.The concentration difference between the minimum effective concentration and the minimum toxic concentration

D.The drug’s clearance times the desired plasma concentration

E.The volume of distribution times the desired plasma concentration

Answer 6

E

Question 7

A 3-year-old child is brought to the ED having just ingested a large overdose of promethazine, an antihistamine. Promethazine is a weak base with a pKa of 9.1. It is capable of entering most tissues, including the brain. On physical examination, the heart rate is 100/min, blood pressure 110/60, and respiratory rate 20/min. In this case of promethazine overdose:

A.Urinary excretion would be accelerated by administration of NH4Cl, an acidifying agent

B.Urinary excretion would be unaffected by administration of NaHCO3, an alkalinizing agent

C.More of the drug would be ionized at blood pH than at stomach pH

D.Absorption of the drug would be faster from the stomach than from the small intestine

E.Hemodialysis would be the only effective therapy

Answer 7

A

Question 8

How will raising the pH of the urine affect the rate of excretion of the weak base morphine?

A.Rate will increase

B.Rate will decrease

C.Rate will be unchanged

Answer 8

B

Question 9

Which of the following statements about drugs that are weak acids is CORRECT?

A.An acid will most readily cross membranes when it is contained in acidic body fluids.

B.An acid will have a pKa greater than 7.0.

C.An acid becomes charged when it takes up a hydrogen ion.

D.An acid will be trapped into more acidic body fluids.

Answer 9

A

Question 10

Lidocaine is a local anesthetic that is a weak base with a pKa of 7.9. Relative to normal tissue pH of 7.4, the ability of lidocaine to cross neuronal membranes in inflamed tissue at pH 6.4 would be:

A.Increased

B.Decreased

C.Unchanged

Answer 10

B

Question 11

Regarding the termination of drug action:

A.Drugs must be excreted from the body to terminate their action.

B.Metabolism of drugs will always increase their degree of ionization.

C.Metabolism of drugs always abolishes their pharmacologic activity.

D.Hepatic metabolism and renal excretion are the two most important mechanisms involved.

Answer 11

D

Question 12

Drug metabolism usually results in a product that is:

A.More likely to cross the blood brain barrier

B.More water soluble than the parent drug

C.More likely to be reabsorbed by kidney tubules

D.More ionized than the parent drug

Answer 12

B & D

Question 13

For drugs that are metabolized by the phase 1 CYP450 (cytochrome P450) enzyme system they:

A.Require molecular oxygen

B.Are generally highly lipid soluble

C.Usually become more highly oxidized

D.All of the above

Answer 13

D

Question 14

Local anesthetics are metabolized in the plasma or liver by:

A.Amidases

B.Esterases

C.Alcohol dehydrogenase

D.Monoamine oxidase

E.Cytochrome 3A4

F.Glucuronyl transferase

Answer 14

A & B

Question 15

A phase II drug metabolism reaction:

A.Must always be preceded by a phase I reaction

B.Includes non-microsomal oxidation reactions (e.g., MAO)

C.Is dependent on molecular oxygen (O2) and NADPH as cofactors

D.Is less likely to reach saturation (VMAX) levels than phase I reactions

E.Will be less likely to decline in activity with aging than phase I reactions

Answer 15

E

Question 16

Which of the following statements concerning drug metabolism is FALSE?

A.Liver is primary organ involved in drug metabolism.

B.Oxidation is the most common reaction.

C.Inhibition of cytochrome P450 enzymes can decrease plasma levels of drug substrates.

D.Drug metabolism can also occur in kidney and intestine.

E.CYP3A4 is the P450 enzyme that metabolizes the greatest percentage of administered drugs.

Answer 16

C

Question 17

The addition of glucuronic acid to a drug molecule:

A.Increases its water solubility

B.Usually leads to activation of the drug

C.Is an example of a phase I reaction

D.Occurs at the same rate in adults and newborn

E.Involves cytochrome P450

Answer 17

A

Question 18

You have a patient taking warfarin and the prothrombin time (a measure of the anticoagulant activity of the drug) is in the correct range. You prescribe a second drug for a dental use and find a week later the anticoagulant effect of warfarin is markedly decreased. This is most likely due to:

A.The second drug inhibiting the metabolism of warfarin.

B.The second drug competing with the same enzymes that metabolize warfarin.

C.The second drug inducing the metabolism of warfarin.

D.The second drug displacing warfarin from protein binding sites.

Answer 18

C

Question 19

All of the following drugs or foods are inhibitors of various cytochrome P450 enzymes EXCEPT:

A.Antifungal agents (e.g., ketoconazole)

B.Cimetidine

C.Grapefruit juice

D.Macrolide antibiotics (e.g., erythromycin)

E.St. John’s wort

Answer 19

E

Question 20

A patient is given a single 200 mg dose of Drug Y and the plasma concentration is obtained at 6 time points afterward as follows. Assume instantaneous distribution of drug.

0 hr ————– 8 mg/L

2 hr ————– 7 mg/L

4 hr ————– 6 mg/L

8 hr ————– 4 mg/L

10 hr ————- 3 mg/L

12 hr ————- 2 mg/L

16 hr ————- 0 mg/L

Based on these data, the volume of distribution of Drug Y is:

Answer 20

Vd = dose / Cp₀

25 L

Question 21

The half-life of a drug:

A.Is dependent on clearance

B.Is dependent on the volume of distribution

C.Is an independent pharmacokinetic parameter

D.Must be known to calculate the loading dose

E.Decreases if the volume of distribution decreases

F.Decreases if the clearance decreases

Answer 21

A, B, E

Question 22

If the plasma concentration of a drug declines with “first-order kinetics”, this means that:

A.There is only one metabolic path for drug elimination

B.The drug is not distributed outside the vascular system

C.The half-life is proportional to the Cp

D.The drug is largely metabolized in the liver after oral administration and has low bioavailability

E.The rate of elimination changes as the plasma concentration changes

Answer 22

E

Question 23

Which of the following drug dosage regimens would result in the GREATEST amount of fluctuation in the plasma drug level during the dosing interval?

A.Drug E (t1/2 = 1.5 hrs) dosed every 8 hours

B.Drug A (t1/2 = 6 hrs) dosed every 6 hours

C.Drug B (t1/2 = 4 hrs) dosed every 18 hrs

D.Drug C (t1/2 = 24 hrs) dosed every 3 days

E.Drug D (t1/2 = 12 hrs) dosed every 6 hours

Answer 23

A

Question 24

A patient is given a single 500 mg dose of Drug Y and the plasma concentration is obtained at 6 time points afterward as follows:

0 hr ————– 8000 mcg/L

2 hr ————– 7500 mcg/L

4 hr ————– 7000 mcg/L

8 hr ————– 6000 mcg/L

10 hr ————- 5500 mcg/L

12 hr ————- 5000 mcg/L

16 hr ————- 4000 mcg/L

24 hr————– 2000 mcg/L

Are these data are consistent with first order or zero order elimination kinetics?

Answer 24

Zero order elimination kinetics.

Rate stays constant regardless of plasma concentration

Question 25

Erythromycin is an antibacterial agent with a half-life of 6 hours. The prescribed dosage regimen is 500 mg every 6 hours. After 48 hours of therapy the patient shows no improvement and the antibiotic is switched to vancomycin (half-life of 12 hours). If the dosage regimen is changed to 1000 mg every 12 hours, how will the time to achieve the new steady state change?

A.Increase

B.Decrease

C.No Change

Answer 25

A.

Time to steady state Cp_ss when giving a maintenance dose at a fixed interval (MD/t) is solely dependent on the half-life of the drug (reached in 4-5 half-lives).

Whenever the RATE IN (MD/t) or the RATE OUT (CL) is changed it will also take 4-5 half-lives to reach the new Cpss

Question 26

Erythromycin is an antibacterial agent with a half-life of 6 hours. The prescribed dosage regimen is 500 mg every 6 hours. If the dosage regimen is changed to 1000 mg every 6 hours, how will the steady state plasma levels change?

A.Increase

B.Decrease

C.No Change

Answer 26

A.

Steady state Cp_ss levels will change in direct proportion to changes in the RATE IN (MD/t).

Question 27

Erythromycin is an antibacterial agent with a half-life of 6 hours. The prescribed dosage regimen is 500 mg every 6 hours. If the dosage regimen is changed to 1000 mg every 6 hours, how will the fold-fluctuations in steady state plasma levels change?

A.Increase

B.Decrease

C.No Change

Answer 27

C

Fold-fluctuations in Cp_ss levels change in direct proportion to changes in dosage interval (t).

Fold-fluctuations correlate with half-lives in the dosing interval: 2 t / t_1/2

Question 28

In the presence of buprenorphine, a higher concentration of morphine is required to elicit full pain relief. Buprenorphine by itself has a smaller analgesic effect than does morphine, even when given at the highest dose. Based on this information alone, which of the following can be concluded regarding these medications?

A.Buprenorphine is a competitive antagonist

B.Morphine is a full agonist and buprenorphine is a partial agonist

C.Morphine is more efficacious than buprenorphine

D.Buprenorphine is less potent than morphine

E.Buprenorphine is a noncompetitive antagonist

Answer 28

C

Question 29

The following equation describes the hyperbolic relationship between the dose of a drug administered and the magnitude of the response obtained:

E / E_max = D / (ED₅₀ + D)

The term E_max in this equation is best described as a measure of the:

A.The potency of the drug

B.The concentration of the drug

C.The power of the drug to bring about a response

D.The dose of the drug necessary to bring about the maximum response

Answer 29

C

Question 30

The dose response equation in Question 26 above also shows that:

A.Emax will always be larger than EC50

B.The size of EC50 depends on the dose of the drug.

C.The size of the Emax depends on the dose of the drug

D.There is a limit to the increases in response that can be achieved by increasing the dose.

E.If the dose is very large compared to EC50 the response will nearly double when the dose is doubled.

Answer 30

D

Question 31

Symptoms of allergic rhinitis include nasal congestion (vasodilation) and runny nose (edema) caused by histamine’s interaction with H1 receptors on blood vessels. Loratadine is a treatment of choice, working via a competitive blockade of histamine H1 receptors on blood vessels. The role of loratadine in the treatment of allergic rhinitis is best described as:

A.Chemical antagonism

B.Noncompetitive antagonism

C.Partial agonism

D.Pharmacologic antagonism

E.Physiologic antagonism

Answer 31

D

Question 32

Drug X (EC₅₀ = 2.5 mg/kg) and Drug Y (EC₅₀ = 10 mg/kg) both act on the mu opioid receptor to produce a strong analgesic effect. The maximum response produced by Drug X is equal to that produced by Drug Y. Based on these data it is most correct to say:

A.Drug X is more powerful and less potent than Drug Y

B.Drug X is equally powerful but less potent than Drug Y

C.Drug X and Drug Y are partial agonists

D.Drug Y is more powerful and less potent than Drug X

E.Drug Y is equally powerful but less potent than Drug X

Answer 32

E

Question 33

A noncompetitive irreversible antagonist:

A.Causes the potency of an agonist to increase

B.Causes the EC50 of an agonist to increase

C.Has no effect on the potency of an agonist

D.Causes the Emax of an agonist to increase

E.Causes the Emax of an agonist to decrease

Answer 33

C, E

Question 34

Symptoms of viral colds include nasal congestion (vasodilation) and runny nose (edema) caused by the interaction of histamine with H₁ receptors on blood vessels. Phenylephrine (Neosynephrine® nasal spray) is a treatment of choice for cold symptoms, working via an agonist action on a₁-adrenergic receptors on blood vessels to cause vasoconstriction. The role of phenylephrine in the treatment of allergic rhinitis is best described as:

A.Chemical antagonism

B.Noncompetitive antagonism

C.Partial agonism

D.Surmountable antagonism

E.Physiologic antagonism

Answer 34

E

Question 35

In the presence of naloxone, a higher concentration of morphine is required to elicit full pain relief. Naloxone by itself has no effect. Which of the following is correct regarding these agents?

A.Naloxone is a noncompetitive antagonist

B.Morphine is a full agonist and naloxone is a partial agonist

C.Morphine is less efficacious than naloxone

D.Morphine is less potent than naloxone

E.Naloxone is a competitive antagonist

Answer 35

E

Question 36

The standard safety margin is superior to the therapeutic index in evaluating the safety of a drug because:

A.Standard safety margins are more easily determined than therapeutic indices.

B.Data on standard safety margins are more widely available than data on therapeutic indices.

C.The therapeutic index often exaggerates the danger in the use of a particular drug.

D.The therapeutic index only provides information on the range of plasma concentrations over which the drug is clinically effective.

E.The standard safety margin takes into account the response of individuals at the extremes of the population dose-response curves for therapeutic and toxic effects.

Answer 36

E

Question 37

Data regarding comparison of the maximal efficacies of two drugs is best obtained from:

A.Graded dose-response curves

B.Quantal dose-response curves

C.Population dose-response curves

D.Plasma drug concentration versus time curves

Answer 37

A

Question 38

Which of the following poisoning interventions act primarily via increasing the elimination of the toxin?

A.Adsorption of the toxin in the GI tract with activated charcoal

B.Alkalinization of the urine with sodium bicarbonate

C.Gastric lavage with saline solutions

D.Induction of emesis with syrup of ipecac

E.Producing a cathartic effect with 70% sorbitol

Answer 38

B

Question 39

For the majority of poisoning cases, the mainstay of treatment will be:

A.Administration of activated charcoal

B.Administration of osmotic cathartics

C.Alteration of urinary pH

D.Emptying of stomach contents with gastric lavage

E.Hemodialysis

F.Induction of vomiting with syrup of ipecac

G.Support of vital functions

Answer 39

G

Question 40

Prevention of the formation of toxic metabolites is utilized in the management of poisoning with:

A.Drugs with small volumes of distribution

B.Drugs that are weak acids or weak bases

C.Methanol

D.Acetaminophen

E.Mercury

F.Ethylene glycol

G.Inducers of CYP450

Answer 40

C, F