pharm exam 1 Flashcards
Srna
non-competitive antagonist and EC50
irreversible binding to allosteric site, doesn’t change EC50 but lowers the Emax because it doesn’t matter how much agonist you give, it cannot reach its original Emax examples :
Aspirin, Phenoxybenzamine ( alpha 1 antagonist )
competitive antagonist
reversibly bind to the receptor site. it changes EC 50 curve to the right but it does not change Emax
examples: neuromuscular blockers, atropine
what does pharmacokinetics intel
Administration
Distribution
Metabolism
Elimination
propanolol
non selective Beta blocker
indirect antagonism
binding to the agonist and not to the receptor
example: protein binding to heparin
1+1=2
addition
1+1=3
synergism,effect of 1 drug is enhanced by a drug that has no effect on its own. 2 drugs
1+1=0
antagonism
ephedrine
Mephentermine, ephedrine, and metaraminol are mixed-acting drugs. Ephedrine increases blood pressure and has a positive inotropic effect. Because it does not have detrimental effects on uterine blood flow, ephedrine is widely used as a pressor in hypotensive parturient patients. As a result of its β1-adrenergic–stimulating effects, ephedrine is helpful in treating moderate hypotension, particularly if accompanied by bradycardia. It also has some direct β2-adrenergic–stimulating effects and has been used orally as a bronchodilator. The usual dose is 2.5 to 25 mg given intravenously.
**amphetamine works by being taken up by VMAT 2 (which takes up space in the vesicle instead of dopamine or NE) this increases dopamine and NE realease into the synapse; 2. amphetamine competes with with NE or DA for reuptake so less NE or DA is reuptake; 3 MAO is inhibited.
1+0=3
potentiation: only one drug is enhanced :: physostigmine and Ach
what makes the therapeutic index
Ed 50 and the LD 50
pharmacodynamic responses can be:
therapeutic, toxic or lethal
fundamental of pharmacokinetics
volume and clearance
7 factors that affect absorption:
blood flow, total surface area, time to arrival and contact time, solubility, chemical stability, lipid to water partition coefficient, and degree of ionization (Pka)
distribution depends on: (4)
Blood flow, Capillary permeability, Protein binding, Disease States
why os important to know the volume of distribution of a drug ?
to determine the drug’s dosing requirements
body mass %: VRG, muscle,
CO output %: VRG, muscle
10, 50, fat 20, poor 20
75, 20, fat 5, poor 0
formula of volume of distribution
Vd= amount of drug/ desired plasma concentration
volume of distribution is affected by 1.drug characteristics and 2. patient characteristics :
- molecular size, ionization, protein binding,
2. pregnancy and burns
clearance is 1. directly proportional and 2. is indirectly proportional to :
- blood flow, extraction ration and drug dose
2. half life and drug concentration in the central compartment
steady state is
giving and clearing from body at the same amount: rate of administration= rate of elimination
to keep a certain dose in body like dilantin you measure the level of the dose .
plasma concentration curve
alpha: distribution (1/t alpha) and beta: elimination from the central compartment (1/2t beta)
rank opioids potency 1 highest to 5 lowest
- sufentanyl 2. remifentanyl 3. fentanyl 4. alfentanyl 5.morphine 6. demerol
acid donates
H+
base donates
OH-
the amount of ionization depends on two things:
pH of the solution and the pKA of the drug
when the pKa and the pH are the same
50% of drug is ionized and 50% unionized
which creates the strongest gradient for passage of local anesthetic from mother to fetus?
alkalotic mother to acidotic fetus
what drugs bind to beta globulin proteins ? decrease? increase?
basic drugs
nothing , nothing
what drugs bind to alpha1 acid glycoprotein? what lowers ? increase?
basic drugs
- pregnancy, and neonates
- surgical , stress, MI , advanced age , chronic pain, and RA
what drugs bind to albumin ? decrease? increase?
acidic blood:
- advanced age, malnutrition, pregnancy, liver and kidney disease
- nothing
protein binding % fo propofol, diazepam, midazolam, dexmedetomidine, lorazepam, barbiturates, etomidate, ketamin ?
propofol 98% diazepam 98% midazolam 94% dexmedetomidine 94% lorazepam 90% barbiturates 85% etomidate 75% ketamin 15%
examples for zero oder drugs?
logarithmic. there’s more drug the enzyme, linear.
aspirin, dilantin, alcohol, heparin, warfarin and theophylline
examples of first order drugs?
there is the less amount of drug than enzyme. no saturation. a drug can change from 1st order to zero
pharmacokynetic age difference between newborns and older people?
newborns:
- Tend to metabolize drugs more slowly
-Exception is theophylline (more rapidly)
-Digoxin (similarly metabolized)
older people:
-Altered drug distribution
-Lean body weight to fat ratio.
-Metabolic activity of liver.
-Principally P450 enzymes.
metabolism is affected by? (6)
- Age
- Sex
- Liver function
- Nutrition
- Environment
- Genetic factors
phase 2 of metabolism : common substrates are? (4)
glucoronic acid, glycine, acetyl acid , sulfuric acid, or a methyl group
enterohepatic recirculation medication example?
diazepam
how is lidocaine and succinylcholine metabolized in phase one?
hydrolysis
enzyme induction ?
Dilantin Rifampin Barbiturates (phenobarbital) Ethanol Tobacco Carbamazepime
enzymes inhibitors?
Ciprofloxacin Cimetidine INH Erythromycin Grapefruit juice Omeprazole SSRIs Ketoconazole (Diego’s can’t see their fungus)
Disulfiran
antabuse; Disulfiram is an oral drug used for treating alcoholism. Alcohol is converted in the body into acetaldehyde by an enzyme called alcohol dehydrogenase. Another enzyme called acetaldehyde dehydrogenase then converts acetaldehyde into acetic acid. inhibiting acetaldehyde dehydrogenase causes hangover effect . also a Dopa-beta hydroxyls inhibitor
Acetazolamide (diamox)
it makes urine basic therefore excreting acidic drugs
pseudocholinesterase breaks down
succ, local anesthetics (tetracaine, procaine chloroprocaine, cocaine -also hepatic)
non specific esterases
remifentanyl, esmolol, etmoidale (also hepatic) atracurium (also in Hoffman)
non specific esterases breaks down:
remifentanyl, esmolol, etmidate (also hepatic) atracurium (also in Hoffman)
alkaline phosphatase breaks down :
fospropofol
Hoffman elimination is
cisatrucurium, atracurium (plasma esterase)
Children exhibit different pharmacokinetics from adults because
of their altered protein binding, larger volume of distribution (Vd), smaller proportion of fat and muscle stores, and immature renal and hepatic function
old people and metabolism
- decrease albumin, decrease in blood volume by 20-30%^, ^ in body fat (^ reservoir) , decrease in muscle mass, 60% of the GFR of that of a young adult.
Vecuronium will last 45 mins instead of 16 (young adult)
diazepam will last 72 hr instead of 24 hr (young adult)
Fentanyl will last 925 mins instead of 250 mins ( Y.A.)
versed will last 4.3 hrs instead of ( 72 hr)
inhalation agents decrease linearly with older age
enantiomer drugs that are racemic mixture are ?
rupivacain and levobupivacaine
weak base are meds morphine, thiopental, ephedrine, metohexital (pick 2)?
morphine and epinephrine
autonomic nervous system is part of what division ?
motor division
preganglionic fibers are
myelinated and Fiber B
postganglionic fibers are
unmyelinated and fiber C
blocking T4 will cause
Bradycardia and hypertension
acetylcholine is terminated by :
cholinesterase
norepinephrine is terminated by:
reuptake into the nerve terminal, diffusion out of the synaptic cleft, metabolic transformation by the MAO, or COMT by the liver
epinephrine terminated by
COMT
membrane bound receptors
Ion Channels
G-Protein Coupled Receptors
Enzyme Linked Receptors
Intracellular Receptors
example of enzyme linked receptors
insulin
example of intracellular receptors
steroids, and thyroid hormone
cAMP functions?
activates protein kinase, phosphorylates 3 reactions–> Ca+ channels, myosin like chain kinase MLCK, phopholamban
cAMP functions?
in the cardiac muscles : phosphorylates protein kinase and increases intra cellular Ca+ therefore increase contractility and phospholyrates phopholamban.
in the vascular smooth muscle: cAMP inhibits myosin like chain kinase MLCK causing vasodilation and decreasing SVR
phospholamban
protein that regulates the Ca+ pump in the SR in cardiac muscles so it bring the Ca+ back into the SR. so it causes lusitropy.
MLCK
myosin like chain kinase:
alpha 2 receptors are located
presynaptic, postsynaptic, and platelet
Dexmedetomidine is a centrally acting alpha-2 agonist reducing:
reduces SNS tone and causes sedation, MAC reduction, bradycardia, and vasodilation
Alpha 2 in my spinal cord will
cause analgesia, anti-shrivering
thiophyllin is
non selective PDEI
primacor (Milrinone)
PDE3i
cAMP reactions
cardiovascular: increase lusitropy and increase inotropy
vascular muscle: relaxation , and vasodilation
activation of PKA
lypolysis , glycogenolysis and protein synthesis somewhere else
Inodilators are also known as
PDE3i
rate limiting stop
tyrosine hydroxyls
what is the primary mechanism of NE removal?
reuptake into the presynaptic nerve
final metabolite oo Ne
vanillylmandelic acid VMA
how do you know if a person has pheocromocytoma?
VMA in urine
Preganglionic neurons
between segments T1 and L2 – lateral gray horn of spinal cord
Sympathetic chain ganglia
paired. visceral effectors , thoracic cavity, head, body wall , and limbs
3 types of sympathetic ganglia
(sympathetic chain) Paravertebral, (collateral ganglion) prevertebral, and adrenal medulla