pharmacology Flashcards
How do aquaretics reduce preload?
Vasopressin (ADH) receptor antagonists
where does gentomycin act in the kidney
on the apical membrane of the proximal tubule
clinical uses of osmotic diuretics
raised intracranial P intraoccular P prevention of acute renal tailure
clinical use of spironolactone
in combination with loop or thiazide diuretics heart failure hyperaldosteronism
how do aldosterone receptor antagonists reduce preload?
Inhibit aldosterone action on the cortical and distual tubules of the nephron (K+ sparing - monitor for hyperkalaemia)
adverse effects of loop diuretics
hypokalemia metabolic alkalosis hypovolaemia hypotension
adverse effects of spironolactone
hyperkalemia GI upset
where do the 4 types of diuretics act?
loop diuretics - ascending limb of loop of henle
thiazide diuretics - distal tubule
K+ sparing diuretics - collect duct
osomotic diuretics - mainly proximal tubule
onset and duration of triamterene and amiloride
tiamterene: onset - 2hours, duration 12-16hrs amilordie: onset: slow, duration 24 hours
furosemide is what kind of drug
Diuretic
clinical use for loop diuretics
salt and water overload hypertension
distal consequence of loop diuretics
increases the osmotic P in the distal tubule –> reducing water reabsorption in distal tubule
mechanism of diuretics
increase Na and water excretion from kidney lowering blood volume and blood pressure
mechanism of action of gentomycin toxicity on the kiney
bins to phsopholipids and effects calcium levels –> effects mitochondria –> cell damage –> apoptosis
mechanism of action of spironolactone
acts as an aldosterone R antagonist - decreases activation of Na channels in the Collecting duct - decreases the stimulation of Na pump synthesis this reduces osmotic P and therefore reduces water reabsorption
What is “The Triple Response”?
The actions of histamine: Reddening - due to vasodilatation at initiating site Wheal - due to increased vascular permeability (localised oedema response) Flare - spreading response through the sensory fibres
How do diuretics reduce preload
Act on the loop of Henle to decrease Na and Water reabsorption –> increase urine output –> decrease blood volume
onset and half life of spironolactone
slow onset short half life of 10 mins, but metabolite longer half life of 16 hours
mechanism of action of osmotic diuretics
decrease the passive reabsorption of water, with only a small decrease in Na reabsorption
3 types of drugs that can act on kindeys
1) diuretics 2) drugs that alter pH of urine 3) drugs that alter secretion of organic molecules
4 types of diuretics?
loop diuretics thiazide duiretics osmotic diuretics postassium sparing diuretics
mechanism of action of thiazide diuretics
inhibit the Na/Cl cotransporter in the distal convuluted tubule –> decreasing the osmotic P and therefore reducing water reabsorption
loop diuretics - mechanism of action
the Na/K/Cl carrier in the ascending limb of the loop of henle –> decreases the hypertonicity in the interstitium, decreasing osmotic P and therefore reduces water reabsorption
what are the effects of gentomycin kidney toxicity
proteinuria
decreased GFR
altered concentrating ability
