Applied Pharmacology for the Dental Hygienist 7th Edition by Elena Bablenis Haveles - Test Bank

MULTIPLE CHOICE

     1.   A drug is defined as a biologically active substance that can modify:

a.	the environment.
b.	the pH of tissue.
c.	cellular function.
d.	immune response.

ANS:  C

Correct: A drug can modify cellular function. A general understanding of drug action allows the dental hygienist to make informed decisions regarding possible drug interactions or adverse reactions for the patient.

Incorrect choices: It is a concern that discarded drugs may be affecting the environment, but this is not the definition of a drug. Some drugs may have the capacity to modify body compartment pH; however, this is not the definition for a drug. Some drugs may have the capacity to modify the immune response, but this is not the definition of a drug.

REF:   Introduction | p. 11                           OBJ:   2

     2.   In comparing two drugs, the dose-response curve for the drug that is more efficacious would:

a.	be closer to the y axis.
b.	be farther from the y axis.
c.	have a greater curve height.
d.	have a higher median effective dose (ED50).

ANS:  C

Correct: Efficacy is an expression of maximum intensity of effect or response that can be produced by a drug.

Incorrect choices: The other choices refer to indicators of drug potency, not efficacy. The potency of a drug is a function of the amount of drug required to produce an effect. The potency of drug is shown by the location of that drug’s curve along the log-dose axis (x axis).

REF:   Characterization of Drug Action (Efficacy) | p. 12              OBJ:   1

     3.   Administering a drug of greater potency is better because drugs of greater potency do not require as high a dose.

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:  D

Correct: The first part of the statement is false, the second part is true. The absolute potency of a drug is immaterial as long as the appropriate dose is administered. If equally efficacious, both drugs will produce the same effect.

Incorrect choices: Both meperidine and morphine, for example, have the ability to treat severe pain, but approximately 100 mg of meperidine would be required to produce the same action as 10 mg of morphine. The dose of meperidine needed to produce pain relief is larger than that for morphine. Less potent drugs require higher doses to produce therapeutic effects whereas more potent drugs can reach toxic levels at lower doses.

REF:   Characterization of Drug Action (Potency) | pp. 11-12        OBJ:   1

     4.   Which of the following statements is true regarding the therapeutic index (TI) of a drug?

a.	A drug with a large TI is more dangerous than a drug with a small TI.
b.	The formula for TI is ED50/LD50.
c.	ED50 is 50% of the effective clinical dose.
d.	TI is the ratio of the median lethal dose to the median effective dose.

ANS:  D

Correct: LD₅₀ is the dose causing death in 50% of test animals and ED₅₀ is the dose required to produce the desired clinical effect in 50% of test animals.

Incorrect choices: The greater the TI, the safer the drug. The formula is TI = LD₅₀/ED₅₀. The ED₅₀ is the dose required to produce the desired clinical effect in 50% of test animals, not 50% of the effective clinical dose.

REF:   Characterization of Drug Action (Therapeutic Index) | p. 13         

OBJ:   1

     5.   Which of the following statements is true concerning the mechanism of action of drugs?

a.	Drugs are capable of imparting a new function to the organism.
b.	Drugs either produce the same action as an exogenous agent or block the action of an exogenous agent.
c.	Drugs either produce the same action as an exogenous agent or block the action of an endogenous agent.
d.	Drugs either produce the same action as an endogenous agent or block the action of an endogenous agent.

ANS:  D

Correct: Drugs either produce the same action as an endogenous agent or block the action of an endogenous agent.

Incorrect choices: Drugs do not impart a new function to the organism; they merely either produce the same action as an endogenous agent or block the action of an endogenous agent.

REF:   Mechanism of Action of Drugs | p. 13                                OBJ:   2

     6.   When different drugs compete for the same receptor sites, the drug with the stronger affinity for the receptor will bind to:

a.	more receptors than the drug with the weaker affinity.
b.	fewer receptors than the drug with the weaker affinity.
c.	all of the available receptors.
d.	none of the available receptors.

ANS:  A

Correct: When different drugs compete for the same receptor sites, the drug with the stronger affinity for the receptor will bind to more receptors than the drug with the weaker affinity