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161 terms

Pharm I exam I

STUDY
PLAY
1gal =
4 L
4 L =
4000mL
1oz=
30grams
1floz =
30mL
1gr =
65mg
1kg=
1000g
drip rate
V/T x C
Vd =
dose (mg) / [in bld]
loading dose =
Vd x [desired in serum]
T1/2=
0.693/ke
ke=
cl/Vd
CLb =
(Vd x k)/ T1/2
extraction ratio =
Ca-Cv / Ca
Clp
rate of elmination /[ drug in plasma]
rate of elmination =
urine flow x [drug in urine]
pharmacology
the sutdy of drugs on biological system
clinical pharmacology
application of pharmacological prinicpals to clinical patients
drug
any substance which can affect a biological system
therapeutic factors taht affect the administration of a drug:
onset of action
site of action
adverse reaction
drug factors that affect the administration of a drug;
ph
solubility
irritability
oral administartion
adv: safe, economical, noninfectious
dis adv: inactivation, palatability, slow onset
IV adminstration
adv: can give large volumes, accurate, and fast onet
disadv: DANGEROUS
SQ administration
adv: slow absoprtion but constant, long duration of acitivyt
disadv: slow onset
IM administration
adv: rapid onset, duration of action is longer than IV
disadv: can cause tissue damage
posology
the study of doses
dose
the amount of drug given to an animal to have an effect
dosage
the amount of drug per unit body weight
types of doses:
therapeutic, lethal, toxic
minimal therapeutic dose
the small amoutn that has a therapeutic effect
maximal therapeutic dose
the largest amount that can be tolerated without producing toxic effects
therapeutic dose
the optimal dose, which lies between the maximal and minimal doses. has a desirabel effect
ED50
Mediam effective dose. affects 50% of the animals
LD50
meidal lethal dose. kills 50% of the animals
toxic dose
the amount that produces undesirable clinical, hematological, biochemical or pathological alterations
relative safety of drugs is calculated by:
therapeutic index
standard safety margin
therapeutic index
LD50/ED 50
the higher the TI the safer the drug
Standard safety margin
ssfactor = Ld1/Ed99
ld1-ed99/ed99 x 100 is a percent that is more accurate then TI
anesthetics can be harmful to...
small mammals and breeds with short respiratory tracts
cows lack ______ on certain organs?
adrenoreceptors
dont use ______ on rabbits
TELAZOL
glucuronyl transferase
an enzyme tha tis used for conjugation. NOT IN CATS!!! will help to metablize salicylate (asprin).
the half life of asprin in cats will _______ due to little of what enzyme?
increase, glucuronyl transferase
opiods in cats will cause miosis? T or F
FALSE!! causes mydriasis
asprin use in dogs....
will cause an inflammatory reaction due to the convertion of arachadonic acid to leukotrienes instead of PGs
SNP
single nucletotid polymorphisms. in less than 1% of the population. no necessarily in a gene,and do not alwyas affect protein functions
linked SNP
"indicative SNP" are not within the gene. do not affect protein funciton.
causative SNP
affect hte way a protein fucntions. there si coding and noncoding
coding causative SNP
located in the codon region to change the amino acid sequence
noncoding causative SNP
located in the gene regulatory sequence changes the level of gene expression.
what do the young and the old have in common?
-decrease ability to biotransform
-decrease drug excretion
-decrease protein binding
NSAID effect on a nomral patient
will decrease COX-2 = decrease inflammation
decrease COX1 = decrease vasodilation = decrease bld flow to kidney
NSAID effect on hypotenion patient
total lack of blood flow to the kidney. can lead to renal failure
idiosyncrasy
genetically determined unpredictable abnormal reaction to drugs.
fever, uticaria, anaphylaxis
tolerance
resistance to ordinary dose of a drug. decrease responsivness to repeated doses of same or similar drug
corss tolerance
tolerace to a drug type other than the one that induced tolerance
tachyphylaxis
acute tolerance to repeated administration of a drug.
time scale = hours
cumulation
the rate of elminiation is slower then the rate of absorption
drug-drug interaction
occurs following concurrent or sequential administration of drugs.
can be summative, synergistic, additive, or antagonistic.
can be beneficial or toxic
urine alkalizers
enhace the excretion of weak acid drugs by ion trapping
urin acidifier
enhances the excretion of weak base drugs by ion trapping
factors related to the enviornment
stress, diet, temp, humidity, oxygen
absorption
transfer of a drug from the site of injection to circulation
factors that affect absorption related ot the drug:
molecular size
lipid solubility
degree of ionization
dissolution in water
concentration at the site
route of administration
how does molecular size affect absorption?
small = fast absorption, aqueous diffusion or thoruhg a lipid channel
large = absorption is lower via facilitated diffusion or endocytosis
how does lipid solubility affect absorption?
increase lipid content = increase diffusion
increase water solubility= decrease diffusion`
how does ionization affect absorption?
nonionized drugs are more important for passive diffusion
increase NI/I ratio and increase diffusion
how does dissoluiton in water affect absorption?
-oral absorption of a liquid is faster than a solid
how does concentration at a site affect absorption?
- high concentration will increase absorption rate.
how does route of administration affect absorption rate?
oral is slower than injection
SQ<IM<IV< inhalation
factors that affect absorption related to the drug
-blood flow
-absoring surface area
-connective tissue
-species
-individual
how does blood flow affect absorption?
increase blood flow = increase absorption
bld flow can be modified by heat, massage, other drugs, sympathetic NS, and edema
hear tnad kindey disease will.......(bld flow)
increased edema therefore decreased blood flow
shock will ___ blood flow
decrease blood flow therefore decrease absorption.
how does the absorbing surface area affect absoritong?
increase surface area = increase absorption
upper part of the SI is the best area for this
gastric emptying
will determine the rate of absorption in the SI
what about an individual can impact absorption?
physiology
food presense in the GIT
diseases
diarrhea will___ absorption
DECREASE
first pass effect
drug biotransforamtion that will reduce the quantity of drug that reaches circulation.
-per os administration
-occurs due to gastric enzymes
distribution
movment of drugs from blood to tissues
what affects distribution ofa drug?
concentration
make up of the drug
steady state
protien binding
tissue binding
ion trapping
steady state
the formation of a substance is equal to its removal.
affected by area, permability, membranes, bld flow and concentration
tissues that are highly perfused
brain, heart, kidney, liver, endocrine glands
protein binding
bound drugs are inactive and are unable to be filtere, metabolized, or distributed.
-reversible, pro-longs half-life
-keeps the drug high in the plasma low in the tissue.
mostly bind to albumin
what affect does liver failure have on protein binding?!
protein bidning will be decreasebecause the liver amkes the palsma proteins
tissue binding consequences:
may increase the concentration of a drug in a tissue
drug is pulled outof the plasma
the tissue will hold onto the drug which will increase the time the drug is in the body
Nonionized drugs exert a diffusion pressure? T or F
TRUE!!
weak acids are trapped in...
basic compartments
acid compartments trap______.
weak bases
disposition
the study of the movment of drugs across biological memrbanes form the time of absorption until elmination
simple diffuion
movment from high concentration to low concentration. dependent on lipid solubility
partition coefficient
oil : water ratio
increase the ratio = increase passive diffusion
lipophilic and hydrophilic =
ETOH
hydrophobic molceules
O2 and N2
small uncharged polar molecules
urea and water
can passively diffuse
large uncharged polar molecuels
glucose and sucrose
will not diffuse
ions
will not pas the lipid barrier
T or F? It is possible to look at the pK and determine if a drug is a weak acid or base?
FALSE!
strong acid + weak base =
SALT
(Hcl, H2SO4, PO4)
strong base + weak acid =
salt
(NaOH, Ca2OH, KOH)
pinocytosis
specific type of endocytosis in which the cell engulfs the molecule of drug.
often receptor mediated
no electrochemical gradient
one compartment model
all tissues and organs which the drug penetrates behaves as if they were already in equilibrium with the blood
Vd <1 =
stays in blood
Vd =-1 =
wide distribution
Vd > 1 =
very wide distribution
elimination is measure by?
Half-life and total body clearance
most drugs follow_____
1st order kinetics.
1st order kinetics
the rate of removal of a drug from the plasma is proportional to the concentration at a given time
biotransformation
chemical alteration of the drug molecule in the body which will change the physicochemical properties of the drug and its pharmacological activity
sites of biotransformation
liver, intestine, renal tubules, blood
where does biotransformation occur in the liver?
ER ---specifically the microsome
cytochrome P450
"microsomal oxidase system"
P450 system can cause what type of reactions?
oxidation, reduction, hydrolysis, and conjugation
_______ are targets for cytochrom P450 system
lipophilic drugs
consequences of the P450 system
turns drug into a more water soluble form
can cause the amking of toxic or nontoxic intermdiates
______ is an inducer of the P450 system
Phenobarbitol
phase I reactions
"nonsynthetic"
oxidation, reduciton, hydrolysis
consequences of phase I reactions:
may "flag" the drug for furthe reactions
make active or inactivate the drug
may increase or decrease water solubility
may change drug strcture
Phase II reactions:
"synthetic"
conjugation
conjugation
combining a drug ot its metabolite with an endogenous substance
conjugation can occur with:
glucuronic acid---most common!
sulfuric acid
glycine
glutathione
acetylation
does conjugation exist in neonates?
NO
excretion
removal or clearance of a drug out of the body
glomerular filtration
increase bld flow to the kidney = increase filtered volume
affected by milecular size and filter rate
not affect by ionization
slow compared to tubular secretion
tubular secretion
rapid
can move against concentration gradient
carrier mediated
NOT affect by plasma protein binding
passive reabsorption
is important for nonionized lipophilic molecules.
affected by Urine pH and glomerular filtration
highly lipophilic nonelectrolytes are ______ eliminated form teh body
SLOWLY
how is reabsorption afect by urine pH?
change the pH will cause drug trapping and increase elmination of the drug.
how is reabsorption affected by glomarular filtration?
fluid therapy and diruteics will increase renal excretion and decrease tubular reabsorption
hepatic excretion
highly lipid soluble = metabolized first
drugs can go to teh heptic cells or the bile
criteris for going into the bile?
>300MW and polar
steriod are excreted in the_____
BILE
T or F? If there are drugs in the feces this means that there is still a chance for hte drugs to be reabsorbed?
FALSE!
T or F? basic drugs are excreted in milk
TRUE due to ion trapping
pharmacodynamics
what the drug does to the animal
types of pharmacodynamic effects:
adverse, side, therapeutic and toxic
levels of drug action:
system
tissue
cellular
molecular
pharmacological receptors
cell constituents that bind to an agnoist with increase affinity and trigger a cell repsonse.
most are on the cell memrbane
types of receptors:
physiological--- made for endogenous products
drug recptors--GABA
upregulation
the increase in number or sensitivity of receptors
example of upregulation:
hyperthyroidism in cats---will cause tachycardia tdue to an increasein teh B1 receptors
down regualtion
"desensitivation".
decrease inteh nuber or sensitivity of receptors
agonist
causes a physiological effect. mimic
types of agonists:
full
partial
inverse
full agonist
produce maximal repsonse. 100% efficacy
partial agonist
less than maxiaml resposne <100% efficacy
inverse agonist
drug taht binds to a spontaneousy activated cell receptor to turn it off.
acts like an antagonist
antagonist
blocks the response made by agonists
types of antagonists:
competitive
noncompetitive
uncompetitive
competitive antagonist
"sumontable"
binds to the receptor reversibly to prevent the agonist from binding
noncompetitive antagonist
prevents the agonist from having an effect at any concentration due to its irreversible binding
uncompetitive antagonist
binds to a different site than the agonist to prevent its effect
mixed agonist-antagonist
when the drug has an agonist effect onn one receptors and an antagonistic effect on another type
reversible drug-receptor binding is___
WEAK
graded dosedurve measures;
maximal effect
variability
potency
slope
maximal effect
ceiling, plateau, efficacy.
more important than potency.
higher the curve higher the efficacy
measured in Kd
verticle variability
variability in the response due to administration of the same drug does in an individual or group
horizontal variability
variabilty in the response in the dose requried to see a measureable effect (X axis)
potency
the smaller the dose needed to produce an effect the greater the potency
related ot the concnetration that produces Emax
can be obtained form a graded or quntal curve
slope
the slope of the curve indicates the range of doses over which the drug acts.
shallow slope = decreased toxicity
increased slope = increased toxicity
what shape is the graded-dose curve?
SIGMOID
agonist + antagonist on a graded dose curve will display ______
parallel shift to the RIGHT