Chapter 4- Pharmacodynamics

Question 1

Pharmacodynamics

Answer 1

How drug affects patients

- mechanisms of the drug/how affects pts

Question 2

Frequency distribution curve

Answer 2

Graph: number of patients responding with particular drug action at different doses

Question 3

Median effective dose (ED50)

Answer 3

Dose in the middle of the frequency distribution curve; represents the dose required to produce a specific therapeutic effect in 50% of a group of patients

Question 4

Therapeutic Index (TI)

Answer 4

Ratio of a drug’s LD50 to its ED50 (lethal:effective)

Question 5

Median toxicity dose (TD50)

Answer 5

Dose that will produce a given toxicity in 50% of a group of patients

Question 6

Margin of safety (MOS)

Answer 6

Index of a drug’s effectiveness and safety
- calculated as the amount of drug that is lethal to 1% of animals divided by the amount of drug that produces therapeutic effect in 99% of animals (ED99)

Question 7

Dose-response relationship

Answer 7

The way a pt responses to varying doses of a drug

Question 8

Efficacy

Answer 8

Maximum response that can be produced from a particular drug

A drug has greater efficacy if it produces a higher maximal response at the same dose

Question 9

Potency

Answer 9

Amount of drug needed to produce a specified effect

Question 10

Agonist

Answer 10

A drug that activates a receptor and produces the same type of response as the endogenous substance

Question 11

Partial agonist

Answer 11

Medication that produces a weaker, or less efficacious response than an agonist

Question 12

Antagonist

Answer 12

Competes with agonists for receptor binding sites

- a drug that will occupy a receptor and prevent the endogenous chemical from binding to produce its action

Question 13

What parameters would the nurse use to determine whether the average dose of a medication is effective for a patient?

Answer 13

• physical exam
• vital signs
• laboratory values
• efficacy

Question 14

The nurse knows that a drug with a high therapeutic index is

Answer 14

• probably safe

Question 15

While reviewing the drug manufacturer’s package insert, the nurse reads about the dose-response curve. The purpose of the dose-response curve is to illustrate the relationship between

Answer 15

• the amount of a drug administered and the degree of response it produces

Question 16

Affinity for a receptor is most closely associated with a drug’s_____.

Answer 16

Potency