Chapter 3 Drug Action

Question 1

Pharmacokinetics

Answer 1

What the body does to the drug

Question 2

Pharmacodynamics

Answer 2

What the drug does to your body

Question 3

Pharmacokinetic phase

Answer 3

Absorption
Distribution
Metabolism
Excretion

A tablet or capsule taken by mouth goes through three phases: pharmaceutic (the tablet/capsule disintegrates and dissolves and is absorbed), pharmacokinetic ( Including 4 processes that happen to the drug: absorption (absorbing the drug), distribution (distributing the drug to parts of the body), metabolism (how the body transforms the drug) and excretion[elimination]) (how the body gets rid of the drug), and pharmacodynamic (the way the drug affects the body and how the body responds to the drug).

Question 4

Pharmacodynamic phase

Answer 4

Receptor binding
Postreceptor effects
Chemical reaction

Pharmacodynamics: The study of the way drugs affect the body. The detailed mechanism of action by which drugs produce their biochemical and physiological effect. Provides scientific basis for the selection and use of drugs to counteract specific pathophysiologic mechanisms in particular diseases

Question 5

Pharmacokinetics

Answer 5

Drug absorption
Drug movement from GI tract into bloodstream

Disintegration
Breakdown of oral drug form into small particles

Dissolution
Process of combining small drug particles with liquid to form a solution

Absorption methods
Passive transport
-Diffusion
-Facilitated diffusion

Active transport
-Requires energy and carrier substance (enzyme)

Pinocytosis
-Cell carries drug across membrane by engulfing drug particles.

Question 6

Definitions of Onset, Peak, Duration

Answer 6

Onset-Time it takes for drug to reach minimum effective concentration (MEC).
Peak -Highest concentration in blood
Duration-Length of time taken for a drug to exert a therapeutic effect.

Question 7

Drug Interactions

Answer 7

Side effects: Physiologic effects not related to desired drug effects. All drugs have desirable and undesirable side effects. It is important to know that side effects are one of the main reasons that patients stop taking prescribed medications.

Adverse reactions: More severe reactions than side effects. Adverse reactions are unintended and occurring at normal dosages of the drug causing mild to severe side effects including anaphylaxis (cardiovascular collapse). Adverse reactions must always be reported and documented because they represent variances from planned therapy.

Drug Toxicity: occurs when drug levels exceed the therapeutic range: toxicity may occur secondary to overdose (intentional or unintentional) or drug accumulation. Factors that influence drug toxicity include disease, genetics, and age.

Drug interactions: Altered drug effect due to interaction with another drug