Pharmacology Chapters 1-5

Introduction to Pharmacology

Pharmacology

study of drugs that alter functions of living organisms

Drug Therapy (aka pharmacotherapy)

use of drugs to prevent, diagnose, or treat signs, symptoms and disease processes

Medications

drugs given for therapeutic purposes

5 sources of drugs

1. plants

2. animals

3. minerals

4. synthetic compounds (lab produced)

5. Semisynthetic compounds (naturally occurring substances that have been chemically modified)

3 drug classifications

1. via the effect it has on specific body systems

2. via therapeutic uses

3. via chemical characteristics

Drug prototype

individual drugs that represent groups of drugs

the prototype is often the most commonly used and the first of that particular group to be developed

the class of a drug shoes what it does while the prototype,

is the drug that represents the group of drugs as a collective

OTC drugs are regulated by various laws under the supervision of what institution?

FDA

What are the five phases of development for the process of drug approval

1. Phase 0 - Preclinical - animals

2. Phase I - 20 to 80 healthy individuals

3. Phase II - 100 individuals with the disorder

4. Phase III - 1000+ people with the disorder, given placebos at this stage

5. Phase IV - drug onto the market

Which phase of the drug approval process is most important and why

Phase III. This is the phase that is important to establish any adverse effects and understand potential BBWs

Between what two phases of the drug approval process is the drug submitted for FDA approval to confirm its safety and effectiveness?

Phase III and Phase IV

what are schedule I drugs

drugs that have no medical use. Usually these are drugs of abuse/addiction

What are Schedule II drugs

can be addictive but used medically

What are Schedule III drugs

they have less potential for abuse

What are Schedule IV drugs

drugs that are even less addictive

what are schedule V drugs

drugs with the smallest amount of risk for addiction

Manufacturers determine what name of drugs

their trade name

What name of drugs is independent of manufacturers

their generic name

What are the 10 rights of medication administration?

1. right drug

2. right dose

3. right pt

4. right route

5. right time

6. right reason

7. right documentation

8. right pt education

9. right evaluation

10. right to refuse medication

absorption

what occurs from the time the drug enters the body to when it enters the bloodstream to be circulated

agonist

produces an effect

Antagonist

inhibits an effect

Antidote

provides relief from the effect of a different medication

distribution

transportation of a drug throughout the body

excretion

eliminating the drug from the body

First-Pass effect

metabolism of drugs by the liver when they are taken orally

Loading dose

a larger dose than regularly prescribed that helps pt get to a therapeutic level faster

maintenance dose

dose of a drug needed to keep the blood levels stable after the loading dose

serum drug level

a lab measurement of the amount of a drug in the blood

serum half-life

time required for the blood concentration of a drug to decrease by 50%

serum is another name for what

blood

Four steps of the “journey” of a drug throughout the body

1. enter the body

2. circulate in bloodstream to target site

3. act on the target

4. get eliminated from the body

Pharmacokinetics

processes of drug movement through the body via absorption, distribution, metabolism and excretion

(what the body does to the drug)

four steps of pharmacokinetics

1. Absorption

2. Distribution

3. Metabolism

4. Excretion

absorption (first stage of pharmacokinetics)

what happens to a drug from the time it’s introduced to the body until it reaches circulating fluids/tissues

how does fat content effect absorption

more subq tissue = longer time for drug to absorb

how does food effect absorption

a bigger meal = slower absorption

how does a low stomach acidity effect absorption

low acid content in stomach = slower absorption

how does route of administration affect absorption

determined by the first pass effect and whether or not the liver has to metabolize some of the drug first. meds through patches or IVs don’t go through the liver first and need to be metabolized, and therefore they are able to be absorbed faster.

distribution (second stage of pharmacokinetics)

the movement of a drug to the body’s tissues

how does circulation effect distribution

poor circulation of the body means there will be poor circulation of meds

organs with more blood flow receive meds faster than those with less blood flow

how does protein binding effect distribution

proteins carry drugs throughout the body and meds bound to these proteins are unable to be used

what common protein is used to bind to drugs as they are distributed throughout the body

albumin

how does the blood brain barrier effect distribution

the barrier around the brain makes it difficult for drugs to pass through the barrier because it is lipid soluble only

metabolism (third stage of pharmacokinetics)

process of drugs being changed into new and less active chemicals

How does the liver affect metabolism

The liver helps to inactivate drugs before removal

What are the steps to the metabolism of the drug (5)

1. stomach absorbs some of the med

2. med travels to liver

3. liver - first pass effect

4. metabolism in liver

5. med sent into circulation to target tissue

what is the purpose of the P450 enzyme

it is an enzyme found in the liver that metabolizes most drugs to rid them from the body

why is slowing down metabolism dangerous?

It can cause toxic buildup in the body

why is the consumption of grapefruit with some meds so toxic

Grapefruit slows down metabolism and the P450 enzyme which can create toxic buildup in the body

excretion (fourth stage of pharmacokinetics)

elimination of drugs from the body

If a pt is experiencing kidney failure, what should be done with their drug dosage

lower their doses or space them out

serum drug level

amount of a drug in the blood at a given time

serum half life

time it takes for the amount of a drug in the body to dec. to 50% of its original concentration

therapeutic index

margin between effectiveness and toxicity of a med

are drugs with a narrow or wide therapeutic index very dangerous

narrow therapeutic index

toxic concentration

excessive level of medication in the bloodstream d/t too much of a drug taken or lack of efficient metabolism

Does a short half life equate to a slower or faster metabolism

faster

pharmacodynamics

drug’s action on the target cells and the resulting alterations

(aka what the drug does to the body)

difference between pharmacokinetics and pharmacodynamics

kinetics - what the body does to the drug

dynamics - what the drug does to the body

what are the four ways that drugs influence the body via the principle of pharmacodynamics

1. replace

2. increase/stimulate

3. decrease/slow

4. interfere

receptor sites

specialized protein structures that are on cell membranes

how do receptor sites influence the effectiveness of drugs

drugs can be designed to target specific receptors and initiate, limit or prevent a biologic response. This response depends on the attraction to a receptor and the concentration of the drug already @ the receptor site

anaphylaxis (3 characteristics)

1. Hives

2. SOB

3. Hypotension

EMERGENCY - IT IS LIFE THREATENING

stomatitis (1 characteristic)

red, sore mouth

Bone marrow depression (3 characteristics)

1. low RBC

2. low WBC

3. low platelets

CNS impairment (3 characteristics)

1. confusion

2. drowsiness

3. pt safety concerns

Anticholinergic (3 characteristics)

1. dry mouth

2. dry eyes

3. urinary retention

Liver impairment (5 characteristics)

1. jaundice

2. light stool

3. dark urine

4. High AST/ALT

5. Bilirubin

Renal Impairment (3 characteristics)

1. high BUN/creatinine (measure the waste products of the kidneys)

2. Electrolytes

3. Anemia

hypersensitivity

allergy

dependence

physical/psychological need for a medication

carcinogenicity

can cause cancer

teratogenicity

can cause fetal abnormalities

Black Box Warning (BBW)

FDA warnings about meds that can be fatal

What are the 12 important adverse effects of medications to be aware of

1. anaphylaxis

2. stomatitis

3. Bone marrow depression

4. CNS impairment

5. Anticholinergic

6. Liver impairment

7. Renal impairment

8. hypersensitivity

9. dependence

10. carcinogenicity

11. teratogenicity

12. Black box warning

what is the universal antidote for drug toxicity

activated charcoal

Antidote for Acetaminophen

Acetylcysteine

acetylcysteine is used as an antidote for the overdose of which drug

acetaminophen

Anticholinergics antidote

physostigmine

physostigmine is used as an antidote for the overdose of which drug

anticholinergics

benzodiazepines antidote

flumazenil

flumazenil is used as the antidote for the overdose of which drug

benzodiazepines

glucagon is used as the antidote for the overdose of which drug

beta-adrenergic blockers

beta-adrenergic blockers antidote

glucagon

calcium gluconate is used as the antidote for the overdose of which drug

calcium channel blockers

calcium channel blockers antidote

calcium gluconate

cholinergics antidote

atropine

atropine is used as the antidote for the overdose of which drug

cholinergics

digoxin immune Fab is used as the antidote for the overdose of which drug

digoxin

digoxin antidote

digoxin immune Fab

Naloxone (Narcan) is used as the antidote for the overdose of which drug

opioid analgesics

opioid analgesic antidote

naloxone (narcan)

Vitamin K1 is used as the antidote for the overdose of which drug

warfarin

warfarin antidote

Vitamin K1

What are the 6 most important medication rights

1. right med

2. right dosage

3. right documentation

4. right timing

5. right route

6. right patient

CPOE

computerized physician order entry - where physician can put an order directly into the computer

medication reconciliation

when pt level of care changes, ask about what meds are being taken at home at the beginning of their visit and provide a list of meds at the end of the visit of what they are currently taking

enteric coated pill

a pill with a special coating that keeps the pill from dissolving in the stomach

controlled release pills

pills designed to release their contents over a period of time