Chapter 02: Drug Action and Handling
Haveles: Applied Pharmacology for the Dental Hygienist, 7th Edition
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.
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).
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.
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.