Intro to Pharmacology Flashcards
what is the difference between a medicine + a drug (definitions)
Medicine= preparation that contains 1 or more than drugs plus excipients (i.e., solvent, stabilisers, fillers, colouring agents, flavourings, etc.) used to treat/cure/prevent disease
drug= chemical substance of known structure which, when administered to living organism, produces a biological effect (i.e .binds to regulatory molecules + activates/inhibits normal body processes)
define pharmacology
Pharmacology= study of drug characteristics: mechanism of action, effects they have, effects, dosage, usage
define pharmacy
Pharmacy= profession of preparation/ supply of medicine
define clinical pharmacology
Clinical pharmacology= scientific study of drug effects in humans
define therapeutics
Therapeutics= branch of medicine concerned with the treatment of disease
define toxicology
Toxicology= study of undesirable effects of chemical agents (poisons) on living systems. Also includes actions of industrial pollutants, natural organic and inorganic poisons + other chemicals on ecosystems/species.
define drug receptor
DRUG RECEPTOR : The molecular components of the body with which a drug interacts to bring about its effects.
Receptors are generally proteins located on cell outer membranes although other non-protein drug targets exist. They’re targets for drug molecules. Each receptor is specific for a particular drug.
E.g. brain contains:
Cannabis receptors specific for cannabis and morphine receptors for morphine. Morphine will not target cannabis receptors and vice versa. Both receptors are found on the cells of the brain. It is this targeting or specificity which makes drugs function.
define pharmacodynamics
Pharmacodynamics
= what drug does to the body
*biochem + physiologic effects of drugs
* drugs interact w receptors
* they bind to + alter the function of that receptor
define agonist
Agonists
=bind to receptors/activates them (mimic natural ligand of receptor)
*When ligand leaves the receptor, usually deactivates receptor + stops the effect
*Some receptors are permanently activated even after ligand has left - covalent change in receptor
define partial agonists
Partial agonists
=bind to receptor at active site
*Lower affinity to the receptor and do not bind as strongly as a full agonist
*Unable to cause the maximal response even if all receptors are occupied
*Prevent other agonists from binding
define antagonist
Antagonists
= binds to a receptor + prevents activation of receptor
what are the 2 types of drug interactions
allosteric + competitive
what do we mean by a competitive interaction in pharmacology
a specific type of interaction between a drug and its target in which the drug competes with another substance for binding to the same site on the target molecule.
*involves agonists + antagonists
*effects potency + efficacy of drug
describe the difference between agonist + antagonist
Agonists bind to receptors/activates them (mimic natural ligand of receptor)
{drugs with both affinity (they bind to the target receptor) and intrinsic efficacy (they change receptor activity to produce a response).}
Antagonists bind to the target receptor but do not produce a response {i.e. have affinity but zero intrinsic efficacy; therefore they]
what do we mean by affinity of drug
affinity (they bind to the target receptor)
what do we mean by intrinsic efficacy of drug
intrinsic efficacy (they change receptor activity to produce a response).
what do we mean by allosteric interactions
Allosteric interactions:
*Do not act directly on the receptor
*Affect the efficacy or binding affinity
–>Allosteric activators (increase the activation of the receptor)
–>Allosteric inhibitors (decrease the activity of the receptor)
what are the 2 types of antagonist
Competitive antagonist
-Fits into the active site but does not activate receptor and competes for binding site
Reduce agonist potency
-Reversable binding
-Need to add more drug to get to EC50
Non-competitive antagonist
-Binds to a site that is not agonist binding active site
-Modulates function of receptor
-Reduce agonist efficacy
-Irreversible (covalent) binding
-Maximal effect reduced
-EC50 is same dose as for agonist alone
define chemical antagonist
Chemical antagonist= binds directly to an agonist preventing it binding to receptor or substrate (heparin & protamine)
define physiologic antagonist
Physiologic antagonist= 2 drugs have exactly opposite actions via different pathways
what is an inverse agonist, give an example
inverse agonist= a type of ligand that binds to the same receptor binding site as an agonist but induces the opposite pharmacological response compared to the agonist
N.b. like nalaxone (to save patient) –Suppressing basal MU-opioid receptors signalling, complete reversal of opioid drug effects, including respiratory depression
Not only antagonise effects of an agonist, but exert opposite effect by suppressing spontaneous receptor signalling (when present) – Negative efficacy
Only seen in systems that are constitutively active without any binding of ligand/agonist
Decreases the activity below the basal level.
What is pharmacokinetics
Pharmacokinetics
=what body does to the drug
- Liberation: way that a drug is released from its administered form
- Absorption: how a drug travels from site of administration to site of action.
- Distribution: passage of a drug through bloodstream to different tissues in body.
- Metabolism: enzymatic activities that break down a drug
*Excretion: elimination of a drug from body.
what is Pharmacogenomics
Pharmacogenomics
* refers to genetic variability [how our individual genetic make up influences our responses to certain drugs]
*Causing variations in delivery of drug to or removal of drug from sites of action in individuals (involved in efficacy and/or toxicity)
*Problematic for drugs with a narrow therapeutic range or therapeutic. Because small differences may result in therapeutic failure or toxicity
e.g. succinylcholine, Caucasians have enzyme 1,000 fold reduced affinity. So drug has slower elimination
what are 3 pharmaceutical formulation types
*Solid Dosage forms
*Semi-Solid Dosage Forms
*Liquid Dosage Form
