General Principals Flashcards
Define- Drug
any chemical substance, natural or synthetic, which can affect living processes
Define- Pharmacology
the study of drugs and their interactions with living systems
Define- Pharmacodynamics
the study of biochemical and physiological effects of drugs and the mechanism(s) underlying the drug effects
Define- Therapeutics (pharmacotherapeutics)
use of a drug to diagnose, treat, or prevent disease
Define- Toxicology
the study of adverse effects of drugs as they interact with living systems
Define- Pharmacy
the practice of preparing and dispensing drug and providing drug information and pharmaceutical care
Define- Schedule I
drugs with no medical use and high potential for abuse. Ex: heroin, meth, LSD
Define- Schedule V
drugs with low potential for abuse but are made with limited quantities of certain narcotics Ex: Pregabalin
Define- Selectivity
selective toward its receptor site & elicits only the response for which it is given
Define- Reversibility of action
typically only want temporary action for drugs. most drug action is terminated by metabolism to an inactive drug (biotransformation), by excretion (mostly through kidney), or by combination of these mechanisms
Define- Efficacy
Define- Efficacy at receptor level
effectiveness of a drug. Inherent ability of a drug to produce a certain degree of biological activity.
Receptor level: drugs ability to bind with a receptor and elicit a response
Define- Potency
biological activity per unit weight.
Ex: a potent drug produces a greater response at the same mg. dosage in comparison to another drug
Drug Mechanisms: Direct
drug combines with specific receptors in a cell or tissue to produce its response
Drug Mechanisms: reflex
drug exerts action by either stimulating or depressing a particular reflex system
Drug Mechanisms: antimetablolite
drug which is chemically similar to a naturally occurring metabolite and which competes and produces a deficiency of that metabolite in an essential biological system
Drug Mechanisms: Release
drug may produce its effect by causing release of endogenous chemicals such as neurotransmitters and hormones
Signal transduction mechanisms: receptors for hormones/neurotransmitters coupled with G-proteins
Adenylate cyclase/cAMP system
phospholipase C/inositol phosphate system
regulation of ion channels
Signal transduction mechanisms: Receptors for insulin + various growth factors
Tyrosine Kinase
Guanylate cyclase
Signal transduction mechanisms: Intracellular receptors
steroid and thyroid hormones & other agents
Define- Therapeutic Index and formula
Margin of safety.
Lethal dose in 50% over effective dose in 50%
Ture or False: a small Therapeutic index is better for safety over a large number
False, a larger number means there is less overlap which means there is a larger margin for safety
Define- Agonist
drugs that mimic endogenous regulatory molecules and ACTIVATE RECEPTORS (high affinity and high intrinsic efficacy
Define- Antagonist
drugs that block endogenous regulatory molecules and PREVENT RECEPTOR ACTIVATION. (has affinity but NO INTRINSIC EFFICACY)
Define- addictive drug effects (Summation)
summation of effects of 2 drugs (2 + 2 = 4)
Define- Synergism
Effect of 2 drugfs in combination is greater than sum of drugs administered (2+2 = 5)
How can drugs cross membranes?
they are lipid soluble
they have small molecular size
they are uncharged (non polar)
optimal pH
True or False: drugs that are weak acids are unionized in the stomach and tend to be absorbed there
True
True or False: drugs that are weak acids are unionized in the intestines and tend to be absorbed there
False: weak bases, not weak acids
True or False: drugs that are weak bases are unionized in the stomach and tend to be absorbed there
False: weak acids, not weak bases
True or false: drugs that are weak bases are unionized in the intestines and tends to be absorbed there
True
Mechanisms of absorption include what? Hint (4 mechanisms)
Active Transport
Facilitated diffusion
P-Glycoproteins
Pino/phagocytosis
What are P-Glycoproteins? (multidrug transporter proteins)
Transmembrane proteins that transports a wide variety of drugs OUT of cells.
present in: Brain capillaries, liver, kidneys, placenta, intestines
Drug Storage depots. Hint: 4 depots
Fat
Liver
Bone
Skin
Storage Depot: Fat, Why do drugs accumulate here?
drugs localize here because they are fat soluble
Storage Depot: Liver, Why do drugs accumulate here?
many drugs have high affinity for hepatic cells
Storage Depot: Bone, Why do drugs accumulate here?
Tetracyclines have chelating properties and are deposited in areas of calcium, especially bone and teeth
Storage Depot: skin, Why do drugs accumulate here?
drugs localize in skin due to affinity for certain binding sites. Ex: lead in hair; griseofulvin in keratin
Cytochrome P450 (CYP) is found where and does what?
Found: liver, small intestines & other tissues
Function: metabolism (biotransformation)
Metabolism: induction
stimulation of hepatic drug metabolism by some drugs. Enzyme inducers stimulate their own metabolism and also accelerate metabolism of other drugs.
Metabolic reactions Include: hint 2 types
Conjugation
Non-synthetic reactions:
Define- Metabolic reactions: Conjugation (2 parts)
synthetic reaction combining the parent drug with a sugar, amino acid, glucuronic acid, or other naturally occurring compound
Makes drug more polar, water-soluble for excretion by kidneys
define- metabolic reactions: non-synthetic reactions
oxidation, reduction, and hydrolysis (inactivates drug)
define- Prodrug
drugs that are administered in an inactive form and rely on metabolism to convert them to an active substance
First-pass Effect:
significant or complete metabolic inactivation of some drugs by the liver following oral administration.
Define- Enterohepatic recirculation
some drugs or their metabolites, which are concentrated in bile then excreted into the intestines, can be reabsorbed into the blood stream from the lower GI tract
Metabolic Tolerance
due to accelerated drug metabolism
pharmacodynamic tolerance
adaptive processes from chronic receptor occupation
tachyphylaxis
a very rapid tolerance occurring with the first few doses of a drug
What are the 5 drug administration factors?
amount of drug given route bioavailability degree of exposure to a drug multiple drug therapy and drug interactions
