Learn: Intro to Pharm

Selectivity

elicits only responses for which it is given

pharmacodynamics

study of a drug at the site of action and effect it has on the body

pharmacokinetics

study of drug absorption, distribution, metabolism, and excretion

toxicology

study of harmful effects of chemicals (drugs, environmental toxins, and poisons)

absorption

dependent on route of administration, product formulation, gastric emptying, disease states, drug interactions, and pH, and first-pass effect

first-pass effect

after absorption, drug is transported to the liver where a significant amount may be metabolized before it reaches the site of action

bioavailability

extent to which the drug reaches systemic circulation

distribution

dependent on drug characteristics (lipid solubility, molecular size, ionized vs unionized) & binding to plasma proteins (albumin; only free drugs can be transported, disease states or drug interactions can displace drugs from binding and increase drug amount and effect)

volume of distribution (Vd)

body space into which a drug can diffuse

metabolism

phase 1: to make drug hydrophilic, phase 2: conjugate to make more polar for elimination so body cannot reabsorb

elimination

filtration-protein binding and molecular size & charge. Passive transport is dependent on pH and lipid solubility

clearance (Cl)

amount of blood from which all drug is removed per unit of time

half-life

predicts how long it takes dosing regimen to achieve steady state concentration

graded dose response curve

dose vs effect, effective concentration: the dose in a patient that will result in half the maximal effect

potency

related to the dosage that produces a given response in a specific amplitude

Emax

maximum effect produced, potency ≠ maximal efficacy

efficacy

refers to the ability of a drug to bind to the receptors, activate it, and lead to some physiological response

quantal dose response curve

represents dose-response relationships in populations, ex. hyperactive vs hypoactive of % people responding to drug

idiosyncratic drug response

infrequently observed drug effect

hypo-, hyper-reactive

on quantal dose curve

hypersensitivity

allergic reaction to a drug

tolerance

time-related loss of response to a drug (weeks > months)

tachyphylaxis

tolerance that happens very quickly (mins > hours)

therapeutic index

indicator of drug's safety, greater the value of TI, the safer the drug is considered to be

receptors

proteins with unique binding sites that can be located free inside the cell and on the cell surface

affinity

refers to the attraction between a receptor and a ligand (drug)

agonist

a drug that binds to the receptor and causes some type of response, has both affinity and efficacy

antagonist

a drug that binds to the receptor without resulting in any response, has only affinity

second messengers

allow the cell to take an external stimulus and turn it into an internal stimulus (cellular response), allow for quick movement of a signal

signal transduction

a drug binds to the receptor and that receptor becomes activated and propagates a signal. proteins are turned on (phosphorylated) and mobilize second messenger molecules

over the counter (OTC)

drugs that do not require a doctor's prescription can be bought off-the-shelf in stores regulated by the FDA through OTC drug monographs