1. Introduction to Pharmacology Flashcards
what are the 4 things that patients should be informed aobut
why a contrast agent is used
what the contrast agent is
potential adverse reactions associ. w contrast agent
risk factors for potential complications
what is pharmacology
study of drugs in living systems
what is a drug
chemical substance that affects physiological function
how do drugs work? does it create new bio functions
no, it enhances or blocks existing functions
what are the 3 drug nomenclature and what are they based on
chemical name - structure of compound
generic - structure/composition
trade name - brand
what are analgesics, what do they do
relieve pain
what are anxiolytics, what do they do
drugs supress anxiety and relax muscles
what are 3 examples of analgesics
NSAIDS/ibuprofen, paracetamol, tradamol
what are 3 examples of anxiolytics
lorazepam, midazolam, diazepam
what are antiarrhythmics, what do they do
control irregularities of heartbeat
what are 3 examples of antiarrhythmics
adenosine
digoxin
llidocaine
what are antibiotics, what do they do
combat bacterial infections
what are 2 examples of antibiotics
amoxicilin
penicillin
what are anticoagulants, what do they do
prevent blood from clotting
what are 2 examples of anticoagulants
warfarin
heparin
what are antidiabetics, what do they do
used for diabetes
what are 2 examples of antidiabetics
metformin
glipizide
what are anticonvulsants, what do they do
prevent epileptic seizures
what are 3 examples of anticonvulsants
valproate
phenytoin
gabapentin
what are antiemetics, what do they do
treat nausea/vomiting
what are 2 examples of antiemetics
metoclopramide
promethazine
what are antihistamines, what do they do
counteract effects of histamine (chemical involved in allergic reactions)
what are 3 examples of antihistamines
fexofenadine
diphenhydramine
loratadine
what are antihyperlipidemics, what do they do
reduces high levels of lipids in blood
what are 2 examples of antihyperlipidemics
atrovastatin
sinvastatin
what are antineoplastics, what do they do
treats cancer
what are 3 examples of antihyperlipidemics
fluorouracil
carboplatin
melphalan
what are antipsychotics, what do they do
treat symptoms of psychiatric disorders
what are 2 examples of antipsychotics
haloperidol
risperdone
what are betablockers, what do they do
treat blood pressure and angina
what are bronchodilators, what do they do
eases breathing (asthma)
what are corticosteroids, what do they do
reduce inflammation and supress the immune system
what are diuretics, what do they do
promote urine production (gets rid of excess fluid)
what are laxatives, what do they do
increase ease of bowel movements
what are vasoconstrictors, what do they do
help relieve low blood pressure
what are vasodilators, what do they do
dilate blood vessels allowing blood to flow more easily
what are 2 examples of betablockers
metoprolol
propanolol
what are 2 examples of bronchodilators
epinephrine
salbutamol
what are 3 examples of corticosteriods
betamethasone
dexamethasone
prednisone
what are 2 examples of diruetics
bumetanide
furosemide
what is an example of laxatives
bisacodyl
what is an example of vasoconstrictors
norepinephrine
what is an example of vasodilators
nitroglycerin
what is contrast induced nephropathy
who are most at risk
cause of acute renal failure
patients at risk: diabetics, pre-exist renal insufficiency. use of nephrotoxic drugs and dehydration
what is phamacokinetics
study of absorption, distribution and elimination of drugs
what is pharmacodynamics
study of molecular, biochemical and physiological effects of drugs on cellular/body systems and their mechanisms of action
what is pharamacogenomics
study of genetic influences on the effectiveness and fate of drugs
what is toxicology
study of adverse/toxic effects of drugs and other chemical agents
what is the relation between the body and drug in pharmacokinetics
what the body does to the drug
what is the relation between the body and drug in pharmacodynamics
what the drug does to the body
drug concentration relates __ to the ___
what is the relationship trend
dose to the effect
usually proportionally related
what is the dose of a drug
actual amount of drug administered
what is the concentration of a drug
what that dose produces in the body
dose = ___ x ___
conc x volume
what is ADME
absorption
distribution
excretion
metabolism
what is absorption of drugs
drug movement from administration site to the systemic circulation
what is distribution of drugs
reversible movement of drug to the extravascular compartments
what is metabolism of drugs
drug elimination due to the biotransformation
what is excretion of drugs
physical removal of drug from body
why is ADME important
ADME properties of a drug directly influences the concentration time profile in the body
what is the symbol for peak concentration
Cmax
what is the symbol for time to peak concentration
Tmax
what is the major organ that is involved with absorption
GI tract
what is the major organ that is involved with metabolism
liver
what is the major organ that is involved with excretion
kidney
what is the major organ that is involved with absorption and excretion of gases
lungs
what phases of ADME involve movement of drug across biological membranes
all 4
what are the main membranes that a drug has to cross
plasma membranes
what are the 2 components of the plasma membrane
lipid bilayer
proteins embedded in the membrane
what does the plasma membrane do
3 functions
Plasma membrane separates exterior enivro from inner contents of cell
Protective barrier around cell
Regulate what materials can pass in or out
what are transporters and what are the 2 types
proteins that carry substrate in/out of cells
uptake = entry efflux = export substrate out
what are the 3 drug physico-chemical properties
molecular size
lipophilicity
ionisation
how does a drug’s molecular size affect the movement across the membrane
smaller molecule = easier movement across
how does a drug’s lipophilicity affect the movement across the membrane
lipid soluble drugs cross membranes more easily than hydrophilic drugs
how does a drug’s ionisation affect the movement across the membrane
drugs are weak acids/bases and exist in both their ionised and non ionised forms in different ratios depending on the pH of the soln
what do weak acids do when ionised
what charge do they become
give up H+ to become negatively charged
what do weak bases do when ionised
what charge do they become
accept a H+ to become positively charged
as pH increases (more basic) what happens to the ionisation of weak acids
become more ionised
as pH decreases (more acidic) what happens to the ionisation of weak bases
become more ionised
weak acids/bases __ ___ in soln
partially ionised in soln
the ratio between ionised and non ionised weak acids/bases varies with what
pH
the movement towards the ionised form continues until what
when equilibrium is reached between fraction ionised and non ionised
are ionised polar
yes
are non ionised polar
no they are non polar
what form ionised/nonionised crosses the membrane freely?
non ionised form (AH or B)
polar molecules like/dislike water
likes to remain in water
non polar prefers to move into what kind of a environment
lipid environment
can ionised molecules enter the membrane
why/why not
no as low lipid solubility so cant enter unless theres a transporter
what is the pka
pH at which it exists in 50/50 - equal proportions - of its ionised and non ionised forms
A physico-chemical property that controls ionization state when the drug is in soln
what happens when the pH = pka
If Pka drug = ph of soln then 50/50 exist as ionised and non-ionised
if the drug is more acidic, in a acidic soln will the drug exist more in a ionised or non ionised form and what does this mean for its ability to travel through membranes
Amoxicillin acidic so at more acidic soln the drug will exist more in non ionised form so can freely cross membranes
the opposite of this scenario with bases is also true
why is pH important in relation to the pka of drugs
pH of the tissue and the pka of the drug will determine the equilibrium of ionised and non ionised drug
drugs that are weak acids/bases is dependent on what for their ability to cross the membrane
pH of absorption site
weak acids may accumulate in what types of compartments
high pH compartments
weak bases may accumulate in what types of compartments
what is this effect known as
low pH compartments
pH partition
how is the pH partition principle utilised in toxicology and drug overdose
increase drug elimination in drug overdose situations
acidic drugs more ionised in alkaline urine so dont diffuse back into kidney tubules so can be excreted quickly - overdose in acidic drug can use alkaline to speed up elimiation
what are the 5 types of membrane transport
passive diffusion active transport filtration endocytosis facilitated diffusion
why are membranes hard to cross
they are selectively permeable so only allows specific things to pass through as phospholipids are tightly packed and there is a hydrophobic centre
what is passive diffusion driven by and does it use energy
driven by conc gradient and dont use energy
what kind of molecules can pass through lipid bilayer via passive diffusion
molecules must be lipophilic, uncharged and small
what are the 2 types of passive diffusion
transcellular and paracellular
what is a conc gradient and how is this related to molecule movment
difference in conc of a substance across a given space
molecules move from more conc to less conc until they are equally distributed in that space
what is the relationship between the conc gradient and speed of passive diffusion
greater conc diff = faster diffusion
what is transcellular transport and is it the same across all tissues
molecules diffuse across membrane directly
same across all tissues
what is transcellular transport and is it the same across all tissues
what is it dependent on
diffuse through water filled gaps between adjacent cells
tissue dependent and is not the same for all tissues as it is controlled by intercellular junctions
what types of molecule can paracellular transport facilitate movement for
small hydrophilic/water soluble molecules
passive diffusion for those kinds of molecules
what is an example of why paracellular transport is tissue dependent
CNS have tight junctions
liver have larger bigger gaps so easier passage between cells
what is facilitated diffusion and what is it driven by and does it need energy
passive diffusion of drugs through transmembrane proteins
driven by conc gradient, dont need energy
what does facilitated diffusion require
recognition by carrier or channel protein
what kind of molecules can be faciliated by faciliated diffusion
explain why this kind of molecule cant move across the membrane by itself and how facilitated diffusion helps it to do so
Large polar/ionic molecules which are hydrophilic cant cross phospholipid bilayer unaided as charged molecules are repelled by hydrophobic tails in the interior of the phospholipid bilayer
Allow transport of POLAR MOLECULES (endogenous substrate like sugars rather than drugs)
If drug is recognized by channel proteins embedded in membrane can be carried across
Only allow specific molecule to pass so drugs need to resemble endogenous molecules to be recognized
what are gated channels
Gated channels open/close in response to need to cell
what is the difference in the rate of diffusion and saturation ability between passive and facilitated diffusion
facilitated diffusion rate is usually faster and can saturate (can also have competing ligands for the same transmembrane transporter that slows down diffusion) vs passive where it will just diffuse continuously until equilibrium is reached
what does saturability of transporters mean
Saturable as # of substrate molecule per time depends on # of channel/carriers avail per cell
facilitated diffusion is important in which 2 organs
what proteins are involved
kidneys and GI tract
carrier and channel proteins
what doe channel proteins do
transport ions across membranes
what doe carrier proteins do and how do they function
bind to specific molecules and flip between membranes so it is open at different sides of membrane
what is active transport, is it driven by gradient and does it use energy
not driven by conc gradient, acts against conc gradient
uses cellular energy to move molecules against conc gradient, energy from hydrolysis of ATP
what does active transport require in terms of transporters
requires recognition by membrane transporters
is active transport saturable and can it be inhibited
yes it is saturable and can be inhibited by similar structural analogs
how do molecules bind in active transport and undergoes what to allow translocation of membrane to other side of membrane
binds reversibly at specific site, complex underdoes change in conformation which allows translocation of molecule to other side of membrane
active transport allows cell to do what 3 things
accumulate compounds essential for growth
remove waste products
be protected against toxins
what do uptake and efflux transporters do in active transport
uptake transporters allow drug to accumulate
efflux removes drug from cell
what is endocytosis
what is it degraded in and how is it released by cell
drug is taken up by cell in vesicles
degraded by lysosomes and released by cells via exocytosis
is endocytosis energy dependent
yes
what drugs are facilitated by endocytosis
drugs may be quite large >1000Da
what are the 3 types of endocytosis and explain them
pinocytosis = small material and resulting vesicles
phagocytosis = ingest larger materials
receptor mediated endocytosis = specific molecules need to bind and be recognized by receptor on cell surface
what is filtration in transport
molecules passing through fenestrations/pores
most drugs pass through cells to cross biological barriers except at which 2 places and what does filtration there allow
blood capillaries - fenestrations allow rapid exchange between blood and interstitial fluid
glomerular capillaries - extremely porous allowing passage of all plasma constituents except macromolecules
what factor of molecules is a limitation for filtration transport
size - large molecules are too large to diffuse and will be excluded from interstitial fluid
filtration is what kind of a process and relies on what
passive process
relies on pressure gradient
can drugs be transported by a combo of transport mechanisms
yes
what must drugs be to travel via carrier mediated transport
must closely resemble endogenous substrates
