Pharmacokinetics and Pharmacodynamics

Question 1

Pharmacokinetics

Answer 1

The study of drug movement and concentration once it enters the body

Question 2

What four processes drugs undergo in the body?

Answer 2

Absorption, distribution, metabolism, excretion

Question 3

Absorption

Answer 3

Movement of drug molecules from the site of entry into the body to the circulating fluids.

Question 4

Variables that Affect Absorption

Answer 4

• Dosage form
• –Rate of dissolution
• –Nature of absorbing surface/surface area
• –Blood flow to the site of administration
• –GI function
• –pH
• –Presence of food/other drugs
• –Drug concentration

Question 5

Routes of Administration

6 outlined in this lecture

Answer 5

1. Enteral (GI Tract/Intestines)
2. Parenteral (injected)
3. Topical
4. Transdermal
5. Ophthalmic
6. Respiratory Inhalation

Question 6

Types of Parenteral Routes

Answer 6

• IV: Directly into the bloodstream (immediate)
• IM: Injected into skeletal muscle (fast)
• SQ: Injected into connective tissue or fat (slower)
• Epidural: Into epidural space of spinal column (rapid)

Question 7

Distribution

Answer 7

Transportation of the drug to various tissues

Question 8

Variables that Affect Distribution

Answer 8

• Blood circulation adequacy
• – Protein binding
• – Blood-brain barrier

Question 9

What is the relationship between albumin and active drugs?

Answer 9

More albumin, less active drugs

Question 10

Albumin decreases with…

Three things outlined in lecture

Answer 10

• Age
• – Liver disease
• – Poor nutritional status

Question 11

Metabolism

Answer 11

The process by which drugs are inactivated or biotransformed by the body

Question 12

Active Metabolites

Answer 12

Creates a different breakdown that has its own effects

Question 13

Prodrugs

Answer 13

Are given as inactive drugs and are then metabolized into active drugs.

Question 14

CYP isoenzyme

Answer 14

Involves enzymatic alteration of drug structure

Question 15

First-Pass Effect

Answer 15

Drug is metabolized between administration site and systemic circulation or the site of action

Question 16

What is the primary site for metabolizing?

Answer 16

The liver

Question 17

Does IV have a first pass affect? Why?

Answer 17

No. It goes straight into the bloodstream.

Question 18

Variables that Affect Metabolism (not enzyme related)

Answer 18

• Age, Genetics, etc.
• –Nutritional Status
• –Comorbidities
• –Induction/inhibition by substrates also being metabolized
• –Increased # of medications = Increased risk of interactions

Question 19

CYP enzymes

Answer 19

Major enzymes that metabolize drugs

Question 20

CYP Substrate

Answer 20

Substance that is metabolized by CYP pathways

Question 21

Enzyme Inducers

Answer 21

• Substance that increases the production of CYP enzymes
• May lead to decreased drug effects

Question 22

Enzyme Inhibition

Answer 22

• Substance that inhibits/decreases the activity of CYP enzymes
• May lead to enhanced or toxic drug effects

Question 23

Excretion

Answer 23

The process by which drugs and metabolites are eliminated from the body

Question 24

Serum Drug Level

Answer 24

Measurement of the amount of drug in the blood at a certain time

Question 25

Minimum Effective Concentration (MEC)

Answer 25

The required amount of the serum drug level that must be present for the medication to be effective

Question 26

Toxic Concentration

Answer 26

Excessive drug levels in the blood stream

Question 27

Therapeutic Range

Answer 27

• Desired response with no toxicity
• Goal is to maintain drug levels in this range

Question 28

Peak Concentration

Answer 28

• Highest serum level
• Keep below toxic concentration

Question 29

Trough Concentration

Answer 29

• Lowest serum level
• Keep above or near MEC

Question 30

Therapeutic Index

Answer 30

Measure of the relative safety of the
drug

Question 31

Half-Life

Answer 31

Time needed for the drug’s serum concentration to decrease by 50%

Question 32

Bioavailability

Answer 32

The percentage of active drug absorbed and available to reach the target tissues following administration

Question 33

Bioequivalence

Answer 33

A term used to compare 2 products that are:
* – Chemically equivalent
* – Given in the same dose
* – Have the same bioavailability

Question 34

Pharmacodynamics

Answer 34

What the drugs do to the body

Question 35

Drug-Receptor

Answer 35

Reactive cellular site where a drug interacts to produce a pharmacologic response

Question 36

Agonists

Answer 36

Molecules that activate receptors

Question 37

Antagonists

Answer 37

Molecules that block receptors

Question 38

Partial Agonists

Answer 38

Moderate agonist activity

Question 39

Nonspecific Drug Interaction

Answer 39

Produce more general effects on cell membranes and cellular processes. Do not act on receptors.

Question 40

Drug-Drug Interactions

Answer 40

Occur when the effects of one drug are affected by prior or concurrent administration of another drug

Question 41

Most common side effects

Answer 41

Anorexia, Dizziness, Drowsiness, Dry mouth, GI upset, Constipation

Question 42

Types of adverse effects

Seven outlined in lecture

Answer 42

1. Toxicity
2. Allergic reaction
3. Idiosyncratic effect- Uncommon drug response resulting from a genetic predisposition
4. Iatrogenic disease
5. Physical dependence
6. Carcinogenic effect
7. Teratogenic effect- Drug –induced birth defect

Question 43

Nursing Responsibilities to Decrease or Prevent Adverse Effects

Answer 43

1. Take a thorough medication history
2. Identify high risk meds and patients
3. Pregnancy possibility
4. Know and anticipate major therapeutic actions of each drug you give
5. Know and anticipate the major AE of each drug you give
6. Know which drugs are likely to interact with other meds or foods and how it may present
7. Use interventions that can minimize AE

Question 44

Beer’s List

Answer 44

A list of medications we should try to avoid in older adults