Chapter 2: Basic concepts and processes

Question 1

Absorption

Answer 1

Process that occurs from the time a drug enters the body to the time it enters the bloodstream to be circulated

Question 2

Agonist

Answer 2

Drug that produces effects similar to those produced by naturally occurring hormones, neurotransmitters and other substances

Question 3

Antagonist

Answer 3

Drug that inhibits cell function by occupying receptor sites

Question 4

Antidote

Answer 4

Substance that relieves, prevents, or counteracts the effect of a poison

Question 5

Bioavailability

Answer 5

Portion of a drug dose that reaches the systemic circulation and is available to act on body cells

Question 6

Biotransformation

Answer 6

When drugs are altered from their original form into a new form by the body; also referred to as metabolism

Question 7

Distribution

Answer 7

Transport of molecules within the body; after a drug is injected or absorbed into the bloodstream, it is carried by the blood and tissue fluids to sites of action, metabolism and excretion

Question 8

Enterohepatic recirculation

Answer 8

Drugs or metabolites that are excreted in bile reabsorbed from the small intestine, returned to the liver, metabolized, and eventually excreted in urine

Question 9

Enzyme Induction

Answer 9

Production of larger amounts of drug-metabolizing enzymes by liver cells; process accelerates drug metabolism because larger amounts of enzymes = more binding sites = more drug to be metabolized during a given time.

Question 10

Enzyme inhibition

Answer 10

Process in which a molecule binds to enzymes and inhibits their activity

Question 11

Excretion

Answer 11

Elimination of a drug from the body (kidneys, bowel, lungs, skin)

Question 12

First-Pass Effect

Answer 12

phenomenon in which a drug gets metabolized at a specific location in the body that results in a reduced concentration of the active drug upon reaching its site of action or the systemic circulation

Question 13

Hypersensitivity

Answer 13

Immune-mediated reaction to a a drug

Question 14

Loading dose

Answer 14

Dose larger than the regular prescribed daily dose of a medication; used to attain a therapeutic blood level

Question 15

Maintenance dose

Answer 15

Quantity of drug that is needed to keep blood levers and/or tissue levels at a constant/steady level

Question 16

Nephrotoxicity

Answer 16

Toxic or damaging effect of a substance on the kidney

Question 17

Pharmacodynamics

Answer 17

Drug actions on target cells (what the drug does to the body)

Question 18

Pharmacokinetics

Answer 18

Drug movement through the body to reach sites of action, metabolism and excretion (what the body does to the drug)

Question 19

Prodrugs

Answer 19

Initially inactive drugs that exert no pharmacologic effects until they are metabolized

Question 20

Serum drug level

Answer 20

Laboratory measurement of the amount of a drug in the blood at a particular time

Question 21

Serum half-life

Answer 21

Time required for the serum concentration of a drug to decrease by 50%; also called elimination half-life

Question 22

Drug Transport Pathways

Answer 22

Lipid-soluble drugs: just pass through cellular membrane

Protein channels: only some drugs can use this because most drug molecules are too large. Small ions use this pathway but are regulated

Carrier proteins: transport molecules from one side of the cell to the other; selective proteins

Question 23

Drug transport Mechanisms

Answer 23

Passive diffusion - higher concentration to lower concentration

Facilitated diffusion - similar to above except drug molecules combine with a carrier substance (enzyme/protein)

Active transport - drug molecules are moved form an area of lower concentration to one of higher concentration. Process requires a carrier and release of cellular energy

Question 24

Cytochrome P-450 (CYP)

Answer 24

Enzymes in the liver that metabolize most drugs

Question 25

*most drugs act by mechanism of combining with receptor sites on cells

Drugs that do NOT act on receptor sites include…

Answer 25

Antacids: which act to neutralize the acid in gastric parietal cells
Osmotic diuretics: which increase the osmolarity of plasma and pull water of of tissues into the bloodstream
Drugs similar to nutrients (purines/pyrimidines)
Metal chelating agents: combine with toxic metals to form a complex that can be more readily excreted

Question 26

Variables that affect drug actions

Answer 26

Dosage
Route
Drug-diet interactions
Drug-drug interactions

Question 27

Additive effects

Answer 27

Occur when two drugs with similar pharmacologic actions are taken (ethanol + sedative drugs increases sedative effects)

Question 28

synergism

Answer 28

Occurs when two drugs with different sites or MOAs produce greater effects when taken together (acetaminophen [non-opioid analgesic] + codeine [opioid analgesic] increases analgesic effects)

Question 29

Interference of drugs

Answer 29

Interference of one drug with the metabolism of a second drug may result in intensified effects of the second drug.

Question 30

Displacement of drugs

Answer 30

When a drug with a strong attraction to protein-binding sites may displace a less tightly bound drug. This increases the effects of the displaced drug because the displaced drug is freed from its bound form and becomes pharmacologically active. (Aspirin displaces warfarin and increases the drugs anticoagulant effects.

Question 31

Patient-Related Variables

Answer 31

Age
Body weight
Genetics
Ethnicity
Sex