After determining that your patient has overdosed on a narcotic medication causing a decreased respiratory drive, you administer the medication, naloxone that opposes the effects of the narcotic increasing the respiratory drive. This is an example of a/an:

a. Side effect
b. Contraindication
c. Adverse reaction
d. Antagonism

d
Rationale: a. A side effect is an unavoidable, undesired effect seen with therapeutic medicine doses.
b. A contraindication is a situation in which it would be harmful to administer a medication.
c. An adverse reaction is the same as a side effect.
d. An antagonism signifies the opposition between two or more medications such as morphine and naloxone.