Pharmacology Part 1

Question 1

What are the 3 phases of drug action?

Answer 1

Pharmaceutics, pharmacokinetics, pharmacodynamics

Question 2

What is the pharmaceutical phase?

Answer 2

Includes prep of the drug for admin.
Generally role of manufacturers
Nursing role includes dilution, crushing or mixing to prepare for admin.

Question 3

Clinical trials for drugs:

Answer 3

USP-NF: quality standards of drugs and dietary supps.
USP label verifies purity and exact amount of ingredient

FDA: eval and research for drugs/controls whether prescription or OTC drugs may be used for therapy
(must be approved)

Question 4

FDA Review and Approval Process phases:

Answer 4

Phase I: studies safety of med/treat.
Phase 2: studies efficacy
Phase 3: studies safety, efficacy, dosing
Phase 4: studies long-term effectiveness/cost

Question 5

What does pharmacokinetics mean?

Answer 5

What the body does to the drug
-absorption (taken into body)
-distribution (moved into tissues)
-metabolism/biotransformation (changed into a form than can be excreted)
-elimination/excretion (removed from body)

Question 6

What are the route of medication?

Answer 6

Oral:
-80% are oral
-route convenient and economical
-drug is ingested (digested/absorbed by stomach/intestine then enters hepatic portal circulation to the liver) enters general circulation after

Question 7

What can help or delay drug dissolution?

Answer 7

-some products used in drug may bind tighter to the drug molecule delaying drug absorption

-high fat meals can slow the rate at which contents leave the stomach slowing absorption

-pain and stress can trigger SNS slowing movement of GI slowing absorption

Question 8

Routes of administration of drugs:

Answer 8

Sublingual (under tongue and absorbed through mucous membranes into bloodstream)

Transdermal (drug applied to skin/continuous long acting)

Rectal ( absorbed thru mucous membranes may be irregular though or incomplete)

Parenteral: IV>IM>SQ (rapid, avoids unpredictable absorption in GI tract, more costly, cannot b retrieved)

Question 9

What does absorption include?

Answer 9

process of moving drug from site of admin. into circulation

drug must cross many tissue membranes to get to circulation

diffusion occurs along a conc. gradient so available drugs will migrate into cells when conc. is lower (passive diffusion, facilitated diffusion, active transport)

Question 10

What affects absorption rate?

Answer 10

Blood flow, pH, Gi motility, stress, age, disease states, co-admin. drugs or food

Question 11

What is bioavailability of a drug?

Answer 11

Describes what portion of the administered drug is available to produce a pharmacologic response

Oral drug must pass thru intestinal wall and then the portal circulation to liver (both common sites of first pass effect)

Question 12

First pass effect:

Answer 12

allows the live to metabolize or inactivate drugs and potentially harmful substances before they are distributed to the body

Many drugs may be metabolized before adequate plasma concentrations are reached

Question 13

Distribution factors for drugs:

Answer 13

Process of moving drug trough circulatory system to target cells

Degree of distribution depends on physical/chemical properties of a drug, and its ability to penetrate cell membranes, capillaries, blood brain barrier

Solubility of drug: Water vs lipid solubility

Blood flow and if drug can pass blood brain barrier and have higher conc. in brain than skin

Capillary permeability (liver has high allowing drugs to flow through, brain does not)

Protein binding and binding profile will determine extend of drug distribution and elimination rate (only unbound drugs may diffuse thru cap., produce effect, metabolize, excrete)

Question 14

What is the process of metabolism of a drug?

Answer 14

Process of oxidizing drugs into inactive products and conjugating them with new molecules to facilitate excretion

complex liver enzyme system converts lipid-soluble drugs to water metabolites that are easily eliminated by kidneys

Facilitated by cytochrome P450 microsomal enzyme system
-assist in detoxing of unusual chemicals
-find unusual molecules and adds oxygen atoms
making molecules more soluble in water and easier to
flush out the body (O2 also provides ready handle for
other detoxifying enzymes)

Question 15

Phases of metabolism of a drug:

Answer 15

Phase I: oxidation- active compounds into inactive metabolite/ can also do reverse (occurs via cytochrome p450 system)

Phase II: conjugation- adds a polar molecule (ionizes) facilitates excretion of metabolites

Question 16

What affects rates of metabolism?

Answer 16

blood flow, age, nutrition (albumin), liver integrity (enzyme prod.), genetics (enzyme prod.), polypharmacy (drug interaction), microbial flora

Question 17

Process of excretion of drug metabolites:

Answer 17

Mostly renal but can be respiratory or thru skin, bile salts, feces

Good perfusion to kidneys will deliver more conjugated drug to the glomerulus and into filtrate

Low BP will mean little of the drug reaches glomerulus

Large molecules cannot pass thru glomerulus so protein bound drugs will not enter the filtrate; will remain in circulation

Damaged kidney will not be able to excrete drug products

Question 18

Elimination drug factors:

Answer 18

Protein binding affinity

Degree of Ionization
-Ionized drugs tend to remain the circulating plasma which means that they will be delivered to glomerulus and excreted
-Non-ionized will move into cellular environments

Lipid or water soluble:
-lipid soluble drugs will tend to stay in cellular spaces and subcutaneous fat (less likely to perfuse to the kidney)
-tend to excrete more slowly than water soluble
-lipid soluble can be excreted thru lipid breast milk

Question 19

Geriatric Considerations with Absorp., Dist., Metab., and Excretion?

Answer 19

Absorption- decreased cardiac output decreases blood flow to GI tract, decreasing drug absorption

Distribution- Decreased albumin production allows for higher levels of free drug increasing drug effects

Metabolism: Reduced hepatic enzyme activity and reduced hepatic blood flow reduced ability to metabolize drugs, leading to increased duration and effects of drugs

Excretion: Decreased renal function slows renal excretion of metabolites

Question 20

Pediatric considerations:

Answer 20

age based variability in absorption, metabolism, distribution, excretion

weight must be used for calculating precise drug doses

Infants/children have decreased gastric pH

absorption rates of medications can very due to erratic blood flow

infants have higher rates of TBW and lower rates of fat can affect drugs that are more hydrophilic or lipophilic

Question 21

What does steady state mean?

Answer 21

Drugs going in = Drugs going out

this take 4-5 half lives

organ disease or drug interaction can prolong half life

Genetics can also contribute

Question 22

What is the difference between loading and maintenance dose?

Answer 22

Loading dose: able to achieve desired effects faster

Maintenance dose: longer onset for effects usually 4-5 doses before it reaches what a loading does can

Question 23

What is a minimum effective drug dose?

Answer 23

amount of drug needed for desired effect

Question 24

Therapeutic range and what do you use to calculate this?

Answer 24

Drug concentration between minimum effective dose and toxic concentration

Question 25

What does pharmacodynamic’s mean?

Answer 25

What the drug does to the body

Study of biological and physiological effects of drugs and their mechanism of action

Interaction between drug and target cells or cells

Question 26

Drug action within the body:

Answer 26

Drugs can change the environment of body cells (antacids neutralize stomach acidity)

Drugs can bind to receptors on cell membranes and create a signal transduction that will alter cellular physiology

Question 27

What is Agonism? And how does it act?

Answer 27

Agonist is a drug that binds to a receptor and produces a physiologic effect by stimulating the receptor

Question 28

What is antagonism? How does it work?

Answer 28

Drug that binds to a specific receptor and blocks other substances from stimulating the receptor/Do not activate the receptor though like agonist

Question 29

What is affinity and how it affects drug effects?

Answer 29

Receptor shape

Best fit with receptor shape will have maximal effect hence greater affinity

Question 30

What is selectivity? And how it affects drug effects?

Answer 30

Selectivity only means having one effect

Usually means less side effects

Question 31

What is allosteric binding?

Answer 31

When drug binds next door changing the shape of the receptor allowing more of the natural compound to enter

Benzodiazepine

Question 32

Drug effectiveness:

Answer 32

Dose response curve -relates drug dose and magnitude of drug effect

Drugs can have multiple effects

Drugs vary in effectiveness (different sites of action//different affinities for receptors)

Effectiveness is related to its safety (therapeutic index)

Question 33

What is the efficacy and potency of a drug? Which one is more important?

Answer 33

Efficacy: magnitude of max response produced by drug

Potency: Comparing drugs, the more potent will produce therapeutic effect at lower dose

Efficacy more important than potency

Question 34

Drug effects?

Answer 34

Therapeutic-response we hope to achieve
Side effect- develop tolerance
Adverse effects- any undesirable experience associated with use of a medicine

Question 35

Schedules of Drugs:

Answer 35

Schedule I: Illegal substance- marijuana, heroin
Schedule II: high potancy for abuse- opioid
Scheduled III: moderate low potential for abuse- anabolic steroids, ketamine, codeine
Schedule IV: low potential for abuse- Benzos, muscle relaxants, tramadol
Schedule V: lower potential for abuse- cough supp.

Question 36

How to categorize drugs:

Answer 36

Pharmacologic class: drugs that share similar characteristics in their mechanism of action
(beta blockers)

Therapeutic class: therapeutic use (ex:
antihypertensives)