Basics of Pharmacology

drug

any substance which produces a change in function and is used to diagnose, prevent disease, or treat

pharmacokinetics

the process of drug absorption, distribution, metabolism, and excretion

pharmacodynamics

the effects of drugs on the body

efficacy

the ability to improve symptoms

effectiveness

efficacy, tolerability, and safety

must be taken consistently

what must be done for a drug to be effective

FDA

responsible for approving new drugs and monitoring drugs for adverse events, classify drugs as prescription or non-prescription

preclinical testing

FDA drug development process; initial lab tests to determine drug effects and safety; subjects are lab animals

phase 1

FDA drug development process; determine safety and pharmacokinetics; subjects are 20-100 HEALTHY volunteers

phase 2

FDA drug development; assesses drug safety, efficacy, and proper dosing in treating a specific disease; subjects are 100-500 patients WITH DISEASE

phase 3

FDA drug development process; assesses drug safety and effectiveness; subjects are 1000-5000 patients WITH DISEASE

phase 4

FDA drug development process; monitor any problems that occur after NDA approval; subjects are the GENERAL PATIENT POPULATION

orphan drugs

drugs used to treat rare diseases (affecting fewer than 200,000 individuals)

regulate product labeling

FDA's limited role in vitamins, minerals, herbs, nutritional supplements

FTC

maintains authority over supplement advertising

schedule 1

high abuse potential; LSD

schedule 2

high abuse potential; morphine

schedule 3

moderate abuse potential; tramadol

schedule 4

less abuse potential; diazepam

schedule 5

least abuse potential; cough syrups

Drug Enforcement Agency

responsible for enforcing CSA (controlled substance act/drug schedules)

Federal Trade Commission

regulates the trade practices of drug companies and advertising of foods, OTC drugs, supplements, and cosmetics

tablets

must disintegrate; dissolved before absorbed

enteric coated tablets

protect drugs that would be destroyed by gastric acids; Aspirin; sustained or extended release over many hours

syrups

sweetened aqueous solution

elixirs

sweetened aqueous-alcohol solution

suppositories

rectal, localized and systemic effects

inhalation

useful for respiratory disorders, delivers directly to site, minimizes systemic side effects

nasal sprays

delivers drug for localized effect or systemic effects

transdermal patches

drug is slowly released into circulation for up to 1 week

IV

intravenous

IM

intramuscular

SC

subcutaneous

first pass metabolism

drugs extensively metabolized as they pass through the liver for the first time (oral medications)

bioavailability

amount of drug that reaches the systemic circulation

sublingual, buccal, or transdermal routes

what minimizes the effect of first pass metabolism

enteral routes

absorbed in the GI

gastric acid, food, varying rate of gastric emptying

absorption of oral preparations can vary due to what

enemas

suppositories; useful in patients with nausea or vomiting

irregular and incomplete

absorption of suppositories

parenteral route

IV, IM, SC

IV

directly into the circulation, bypasses the process of drug absorption; most dangerous/toxic

IM

delivered the deltoid or gluteal muscle

suspensions or solutions

IM is suitable for what types of preparations

SC

under the skin; can't use if drug irritates cutaneous tissues or large volumes are given; slower absorption than IM

transdermal

application of drugs to skin for absorption into circulation; slowly released over a period of time

inhalation

usually a rapid localized or systemic effect

oral route

adv: many dosages, relatively safe
disadv: inactivated by gastric acid, large 1st pass, food may affect absorption

IM route

adv: absorption is slow for suspensions and rapid for solutions
disadv: painful, causes bleeding

75 to 100

bioavailability for IM

SC route

adv: suitable for suspensions, pellets, absorption is slower than IM
disadv: can't use if drug irritates cutaneous tissues or large volumes are given

75 to 100

SC bioavailability

IV route

adv: immediate effect, rapid titration
disadv: risk toxicity

100

IV bioavailability

rectal route

adv: alternative is nausea or vomiting
disadv: poor absorption

inhalation route

adv: rapid onset, direct application for respiratory disorders, minimizes systemic adverse effects
disadv: difficult to administer, irritation of respiratory tract

transdermal route

adv: promotes steady prolonged delivery of medication
disadv: only suitable for drugs that are effective at low doses

80 to 100

transdermal bioavailability

nonproprietary name

generic name; acetaminophen

proprietary name

trade or brand name; tylenol

same active ingredients, same dosage and route, identical strength

FDA considers drugs to be pharmaceutically equivalent if these 3 criteria are met

therapeutically equivalent and bioequivalent

generic brand must be what

bioequivalent

comparable bioavailability; between 80 and 125% of the name brand

large

biologics size

small

drugs size

complex

biologics structure

simple

drugs structure

heterogeneous

biologics variability

single defined structure

drugs variability

cell bank, unlikely to achieve identical copy

biologics manufacturing

predictable chemical and reagent reaction, identical copy can be made

drug manufacturing

difficult to characterize

biologics characterization

easy to characterize

drugs characterization

sensitive to storage and handling

biologics stability

less sensitive to storage and handling

drugs stability

higher potential

biologics immunogenicity (promote immune response)

lower potential

drugs potential to promote immune response

biosimilars

biological product that is highly similar to an approved biological product; no clinical differences in safety, effectiveness, or adverse effects