Fundamentals of Pharmacology Flashcards
What is pharmacology
Science of drugs
Mechanism of action
What is therapeutics
Medicinal use of drugs
What is pharmacy
preparation and dispensing of drugs
What is toxicology
harmful effects of drugs
what is a drug
chemical substance of know structure, not a nutrient, which when administered to a living organism produces a biological response
How many names do drugs have and what are they grouped by
3 names - chemical, common, trade
therapeutic use (analgesia) and mechanism
What 4 things can drugs bind to and what are these drugs called
Enzymes, ion channels, carrier molecules, receptors (for neurotr and horm)
ligands
what is meant by a drug being an agonist or an antagonist
agonist - activates receptor and produces a response
antagonist - prevents receptor from being activated
What is the mechanism of drug action
drugs are exogenous molecules which mimic or block the action of endogenous molecules
what is meant by selectivity and specificity
for a drug to be useful therapeutically it needs to be very SELECTIVE in its action, however will produce side effects.
solution - design a drug with a high SPECIFICITY to a the target cell
what is meant by pharmacodynamics
what a drug does to the body
what is meant by pharmacokinetics
what the body does to a drug
ADME (absorption, distribution, metabolism, excretion)
what is meant by absorption and what is it affected by
determines how much and how quickly a drug can enter the body.
molecular size, lipid solubility, route of adminis, properties of patient e.g size
what is meant by distribution and what is it affected by
determines whether the drugs effects are local or systematic (travels throughout whole body)
- patients circulation
- does the drug bind to proteins in the blood
- does the drug have access to the organ it will act on
what is meant by metabolism and excretion
determines how long the drugs effects last. drugs are metabolised into metabolites in the liver and excreted by the kidneys.
is the liver healthy, are the liver enzymes effective
what is meant by the half life of a drug + clearance
Affected by met and exc, the time it takes for the drug conc in the blood to half.
volume of blood cleared of the drug per unit time
what is the shape of a drug conc-response curve and log drug conc-response curve
drug conc-response - rectangular hyperbola
log drug conc-response - symmetrical sigmoid
what are the 3 types of pharmacological experiment
in vitro
in vivo
ex vivo
describe how in vitro works
drug effects are studied on a piece of tissue taken from an animal/human and kept alive outside the body
describe how in vivo works
drug effects studied in the living animal/human. eg clinical trials
describe how ex vivo works
tissue removed from an animal/human who was treated with the drug
what is milli, micro and nano
10-3
10-6
10-9
what are the units of in vitro drug conc
Molar (moles per litre)
1 Molar solution=1 mole of drug dissolved in 1 litre of solution
eg. 45mM=4.5x10-2
what are the units of in vivo drug conc
we cant use molar conc as we dont know the volume of solvent eg blood, so we use mg per kg
what is Emax
the maximum response a drug can produce
what is EC50
the conc of the drug which produces 50% of the maximum response
what is meant by potency
describes the conc at which the drug is effective (produces an effective response)
a potent drug is one which is effective in small conc
how do we quantify potency
using EC50
What is the potency ratio (M) and what do we use it to compare
compares the EC50s of 2 drugs.
often we compare a new drug (test) and an already available drug (standard)
How do we calculate the potency ratio (M)
M = EC50 (test) / EC50 (standard)
OR
logM = log EC50 (test ) - log EC50 (standard)
if the value of M is less than 1 what does that mean
M is less than 1 means that the EC50 of the test drug is lower so is potent
what is meant by the therapeutic index
Ratio between the toxic dose of a drug and the dose producing the desired therapeutic effect
if there is a higher therapeutic index, what does this mean
lower chance of the drug producing toxic side effects
what are the 2 therapeutic index formulas
LD50/ED50 (lethal dose in 50% of the population)
TD50/ED50 (toxic)
why is LD50/ED50 not used anymore
death is an extreme side effect
unethical to obtain LD50 values from animals
Problems with TD50/ED50 (used for humans)
Drug effects are different for every person
drug can have different ED50 values depending on the condition being treated
what do receptors do
recognise extracellular molecules
transducers - having detected the extracellular molecules they can then bring about changes in the cell
what is meant by specificity
only one or a few drugs can bind to a receptor
what is meant by affinity
ability of a drug to bind to a receptor
how can we quantify affinity
using Kd - [drug] required to occupy 50% of receptors at equilibrium.
high affinity = low Kd
what is meant by efficacy
ability of a drug to activate a receptor
what are the two types of agonist and explain them
full agonist - has affinity and HIGH efficacy
partial agonist - has affinity and LOW efficacy so less effective
explain the graph for full and partial agonists for p (receptors) against response
full - produces max response while only activating a small number of receptors
partial - fails to produce max response despite occupying all the receptors
what are antagonists
prevent receptor from being activated
act as inhibitors, inhibiting the effects of neuro, hormones etc.
what are the 5 types of antagonists
competitive non competitive chemical pharmacodynamic physiological
what is a comp antagonist
competes with the agonist for the same receptor but doesn’t activate it (has zero efficacy) R or IR
what is a non comp antagonist
acts at a diff site on the receptor, causing a conform change. R or IR
what is a chemical antagonist
uses one drug to chemically inactivate another
what is a pharmacokinetic antagonist
one drug alters the way the body deals with another
what is a physiological antagonist
two drugs act to produce opposing effects, cancelling each other out
describe the graph for rev and irrev comp antagonist
log
symmetrical sigmoid
rev - moves to the right still parallel, effects can be overcome by increasing [agonist]
irrev - curve gets lower and doesn’t reach the same response, inhibition cant be overcome by an inc in [agonist], blockade is not surmountable
