PHARMACOLOGY (principles and transition) Flashcards
therapeutic ratio equation
max tolerated conc divided by min effective conc
why is a low therapeutic ratio bad
means there isnt much difference in an effective conc and a damaging conc = can be dangerous if you dont monitor it
what are the parasympathetic pre ganglionic neurons
ACh
what are the parasympathetic post ganglion neurones
ACh
what are the sympathetic pre ganglion neurones
ACh
what are the sympathetic post ganglion neurones
noradrenaline
which G protein is stimulated by M1
Gq
which G protein is stimulated by M2
Gi
which G protein is stimulated by M3
Gq
which G protein is stimulated by alpha1
Gq
which G protein is stimulated by alpha2
Gi
which G protein is stimulated by beta1
Gs
which G protein is stimulated by beta2
Gs
M1 = Gq =
increased phospholipase C = stomach acid secretion
M2 = Gi =
decreased adenyl cyclase = decreased heart rate
M3 = Gq =
increased phospholipase C = salivary gland secretion, bronchoconstriction, vasodilation
A1 = Gq =
increased adenyl cyclase = vasoconstriction
A2 = Gi =
decreased adenyl cyclase = decreased noradrenaline
B1 = Gs =
increased adenyl cyclase = increase heart rate
B2 = Gs =
increased adenyl cyclase = bronchodilation, vasoconstriction (but vasodilation of coronary vessels = blood gets back to heart)
pharmacodynamic definition
how a drug affects an organism
pharmacokinetic definition
how an organism affects a drug
allopurinol dosage normal
allopurinol dosage renal failure
300mg
<100mg
how does sildenafil (Viagra) work
what is it used for
causes vasodilation = increased blood supply to penis = erection
used for erectile dysfunction
which type of drugs are contraindicated if taking sildenafil (Viagra)
why
vasodilators
which of the following is contraindicated if someone is taking sildenafil (Viagra);
Allopurinol Omeprazole Isosorbide mononitrate Bisoprolol Simvastatin
isosorbide mononitrate (GTN) - causes vasodilation (and so does sildenafil)
which type of drug exacerbates gout
why
loop diuretics
inhibits excretion of urate = high urate = gout exacerbation
which of the following is contraindicated in gout bc it can cause an exacerbation;
Simvastatin Omeprazole Ramipril Metformin Furosemide
furosemide (loop diuretic)
what drug does grapefruit juice pharmokinetically affect;
Bisoprolol Simvastatin Metformin Isosorbide mononitrate omeprazole
simvastatin
which drug effectiveness is decreased by impaired renal function;
Metformin Simvastatin Furosemide Aspirin Bisoprolol
furosemide (loop diuretic)
management of gout flare up (first, second, third line)
first line - naproxen
second line - colchicine
third line - PO prednisolone
contraindication to using naproxen for acute gout flare up management (2)
renal failure/impaired renal function
already on ACEi and diuretic = triple whammy
note: naproxen is a NSAID
what type of drug is naproxen
NSAID
what can ACEi + diuretic + NSAID cause
triple whammy
which of the following is contraindicated for acute gout flare up management in someone with renal failure and already on ACEi and diuretic;
Colchicine Naproxen PO prednisolone IM steroid Intra-articular steroid
naproxen (NSAID)
who are NSAIDs contraindicated in (2)
risk of GI bleed
renal impairment
someone who take warfarin for AF prophylaxis
has renal impairment
needs analgesia for back pain
which is most suitable; Aspirin Diclofenac Paracetamol Ibuprofen Naproxen
paracetamol
NSAIDs contraindicated bc renal failure and increase GI bleed risk??
aspirin contraindicated bc blood thinner and on warfarin
how many days before surgery should warfarin be stopped
5 days
how many days before surgery should aspirin be stopped
7 days
paracetamol overdose management, which is most appropriate;
General supportive measures Gastric aspirations and lavage PO activated charcoal IV N-acetylcysteine Alkaline diuresis
IV N-acetylcysteine
management of hypotension caused by spinal anaesthesia, which is most appropriate;
Clonidine Cyclizine Ephedrine Propranolol GTN
ephedrine - causes vasoconstriction by activating sympathetics
what does ephedrine do
causes release of noradrenaline = sympathetic activation = increases bp
is Vd (volume of distribution) of lipid soluble drugs greater in males or females of same BMI
why
females
bc more fat = more places the lipid soluble drug can be absorbed into
is Vd (volume of distribution) of lipid soluble drugs affected by BMI
why
yes!
bc more fat = more places the lipid soluble drug can be absorbed into = higher volume of distribution (Vd)
is rate of elimination dependent on volume of distribution (Vd)
yes - as Vd increases, rate of elimination increases
may Vd (volume of distribution) exceed the total volume of the body in lipid soluble drugs
yes! it is v large (don’t really understand but KNOW!)
which is true about lipid soluble drugs and their volume of distribution (Vd);
Vd is larger in men compared to women of similar body mass
Vd is unaffected by body mass index (BMI)
Vd is typically less than 5 litre (or approx 70ml/kg)
Rate of elimination if independent of Vd
Vd may exceed the total volume of the body
Vd may exceed the total volume of the body
by which mechanism does spinal anaesthesia cause hypotension
blockade of sympathetic transmission to blood vessels = vasodilation
which of the following is not indicated for secondary prevention of MI after MI
furosemide simvastatin bisoprolol Ramipril aspirin
furosemide
statin, ACEi + beta blocker indicated
aspirin + another antiplatelet indicated
which drug causes hyperkalaemia
by what mechanism
ramipril (ACEi)
ACEi = decreased Na+ reabsorption into blood vessels to decrease bp (water and Na+ out of blood vessels)
Na+ and K+ are opposites - as one goes in, other goes out
which of the following drugs causes hyperkalaemia
Ramipril furosemide metformin allopurinol simvastatin
Ramipril
which of the following drugs doesn’t cause hypotension
isosorbide mononitrate (GTN) furosemide simvastatin Ramipril bisoprolol
simvastatin
statins don’t affect vascular smooth muscle or CO = no effect on hypo/hypertension
which PPI should be avoided if prescribed with clopidogrel ;
dexlansoprazole pantoprazole lansoprazole rabeprazole omeprazole
omeprazole
don’t need to know mechanism
which of the following doesn’t need to be used with caution in patients with renal failure (rest do);
simvastatin allopurinol metformin omeprazole Ramipril
omeprazole - metabolized in the liver
rest are metabolized in the kidneys
steady state plasma conc definition
when rate of administration = rate of elimination
relationship between Vd and loading dose
LD = Vd x target conc
what equation do you use to figure out conc of drug after a certain amount of time if you are given its half life
Ct = Co x (0.5)^n
where n = number of half lifes and Co = initial plasma conc
is half life of drug dependent on dosage
no - they are independent
half life doesnt vary if you alter dose
what happens to length of drug in system if you double the loading dose
it increases by one half life
