Pharmacology Principles

Question 1

3 phases of pharmacology

Answer 1

Pharmaceutic, Pharmokinetic, Pharmacodynamic

Question 2

Pharmaceutic phase

Answer 2

Dissolution occurs—drug begins to dissolve in order to be absorbed; tablet—granula—particle—GI solution—absorption

Question 3

Pharmacokinetic phase

Answer 3

4 stages—absorption into the blood thru the GI tract, distribution at the site of action (effect exerted), metabolism by the liver, excretion by the kidneys (and a small part of the liver)

Question 4

Cell membrane—phospholipid bilayer

Answer 4

Drug passes thru the cell membrane in the intestinal walls to the blood and travels to the site of action if lipid soluble (needs facilitator if water soluble)

Question 5

First pass effect

Answer 5

A % of a drug is broken down by the liver in a first pass before systemic circulation; bioavailability of the drug decreases accordingly for drugs that pass thru the GI tract instead of going directly into the blood (IV)

Question 6

Bioavailability

Answer 6

Amount of drug available in the blood; drugs with lower bioavailability may require higher dose or more frequent dose

Question 7

Where does the first pass effect NOT occur

Answer 7

IV, highly vascularized tissues like SL, buccal, rectal, parenteral, topical meds

Question 8

Enteral

Answer 8

By way of the GI tract (PO, oral, rectal, small intestine); first pass occurs

Question 9

Parenteral meds

Answer 9

SQ, IM, IV, intrathecal (spinal cord), epidural (space around spinal cord); no first pass

Question 10

Topical meds (transdermal)

Answer 10

Apply to body surfaces; eyes, skin, ears, nose, lungs;no first pass effect occurs

Question 11

Distribution

Answer 11

Mvt of drug thru body; drug arrives at site of body

Question 12

What does distribution depend on?

Answer 12

Blood circulation; less blood flow, less circulation; harder to reach tissue (abscesses, tumors, peripheral vascular disease)

Question 13

Blood brain barrier

Answer 13

Cells in capillary wall in brain have tight junctions that prevent drug passage except for lipid soluble drugs; not fully developed in infants; alcohol and glucose can cross

Question 14

Protein binding effect

Answer 14

Temporary storage of a drug molecule that lets a drug be available for longer periods of time; unbound drug binds to a protein and becomes bound; binding is reversible and unbound molecules are active and free to exert effect

Question 15

Goal of dosing

Answer 15

Maintain a steady state of free drug concentrations

Question 16

Albumin

Answer 16

Primary blood protein that molecules bind to

Question 17

Hypoalbuminemia

Answer 17

Low protein levels cause by liver disease or malnutrition; more free drug availability and higher chance of overdose and toxicity (drugs that bind highly to proteins will have a stronger effect on people with low protein levels like Coumadin)

Question 18

Metabolism (biotransformation)

Answer 18

Method by which drugs are inactivated into metabolites; liver converts lipid-soluble drugs into water-soluble metabolites so the kidneys can excrete them

Question 19

CYP450 family

Answer 19

Group of enzymes that metabolize about 1/2 of all drugs; causes lots of drug-drug interactions

Question 20

CYP450 substrate

Answer 20

For metabolism; a substrate (drug) can bind to CYP450 and it will activate the drug

Question 21

CYP450 inducer

Answer 21

Speeds up metabolism of CYP450; causes a decreased amount of a drug in the body and therapeutic effect

Question 22

CYP450 inhibitor

Answer 22

Slows CYP450 metabolism; increased amount of drug in body and increased toxicity (ex: grapefruit juice)

Question 23

Excretion

Answer 23

Removal from body via pee

Question 24

How do the kidneys excrete?

Answer 24

With glomerular filtration, tubular secretion, tubular reabsorption; some drug is excreted and some is reabsorbed in the renal tubules

Question 25

How does kidney disease affect excretion?

Answer 25

Causes toxicity thru improper excretion

Question 26

Half life

Answer 26

Time required for serum concentration of drug to drop by 50%; determines dosing; takes 4-5 half lives to achieve a steady state (drug intake equals amount metabolized/excreted)

Question 27

Around the clock dosing (ATC)

Answer 27

Goal is to maintain 50% concentration in body

Question 28

Drug onset

Answer 28

Time for drug to reach therapeutic response

Question 29

Drug peak

Answer 29

Time to reach max therapeutic effect

Question 30

Drug duration

Answer 30

Time it takes drug concentration to elicit a therapeutic response

Question 31

Pharmacodynamic phase

Answer 31

Drugs can increase, decrease, replace, inhibit, destroy; exert multiple effects on the body (desired, undesired, adverse)

Question 32

Receptors

Answer 32

Proteins on cell surfaces that can be hormones or NTs

Question 33

Agonist

Answer 33

Drug that initiates a therapeutic effect by binding to a receptor

Question 34

Antagonist

Answer 34

Prevents or inhibits/blocks other substances from binding and causing a response

Question 35

Receptor-less activation

Answer 35

No receptor involved; act thru simple physical/chemical intake of small molecules

Question 36

Therapeutic index

Answer 36

Measure of safety; range in which a drug is safe

Question 37

Narrow therapeutic index

Answer 37

Small range of safety for a drug; often monitored with blood tests

Question 38

Black box warning

Answer 38

Required by the FDA for especially dangerous drugs; strongest warning; appears prominently on the package or insert

Question 39

Med errors

Answer 39

Major cause of mortality and morbidity; variables include fatigue and staffing; prevention includes reminders, standardizing, watching for similar drug names

Question 40

High alert meds (Institute for Safe Medicine Practices)

Answer 40

More likely to cause harm (insulin, heparin, opioids, IV, KCl, chemo)

Question 41

Drug-drug interactions increase with…

Answer 41

Especially with NTIs; intended or unintended; polypharm— nurse can bring attention to or may be able to consolidate; food, herbs, and disease

Question 42

Additive effect

Answer 42

2 drugs taken with similar MOA that amounts to a similar effect as that of the drugs separately

Question 43

Synergism

Answer 43

Difference MOA but make an effect greater than 1 drug alone

Question 44

Activation of drug metabolizing enzymes in the liver causes…

Answer 44

Decreased metabolism of the drug

Question 45

Displacement

Answer 45

One drug from a pharma protein-binding site displaced by a second drug and causes an increased effect of the displaced drug

Question 46

Antidote

Answer 46

Antagonized other drug (naloxone)

Question 47

Barrier to intestinal absorption

Answer 47

Lack of anatomy to break down meds