Easy pharmacology Flashcards
Which carrier do loop diuretics inhibit and which ion bit do they bind to?
Na+/K+/2Cl-
Bind to chlorine
Which other ions are excreted when you use loop diuretics?
Ca 2+ and Mg 2+
Additional effects of loop diuretics?
Venodilator
-beneficial in pulmonary oedema caused by heart failure
Which transporter do thiazide diuretics block?
The Na+/Cl-
bind to the Cl- site
Thiazide diuretics, calcium and magnesium
Inhibit secretion of calcium (i.e. less will be excreted)
Increase excretion of magnesium
Additional effects of thiazide diuretics
Vasodilator (can be used in hypertension)
Type of diuretic used in renal stone disease?
Thiazide
reduced excretion of calcium discourages stone formation
Type of diuretic used in nephrogenic diabetes?
Thiazide diuretic, mechanism poorly understood
Diuretics associated with male sexual dysfunction?
Thiazide diuretics
Diuretics associated with impaired glucose tolerance?
Thiazide diuretics
Aldosterone and the Na+/K+ATPase?
Aldosterone increases synthesis of the Na+/K+ATPase
What is ENaC?
Epithelial Na+ channel
Which hormone increases production of ENaC?
Aldosterone
ADH and aquaporins (H20 channels) in the cell membrane?
ADH increases the number of these channels
Why do loop and thiazide diuretics cause potassium loss?
There is an increased Na+ load in the tubule because loop/thiazide diuretic prevented its reabsorption earlier
–> increased Na+ reabsorption –>
Membrane becomes depolarised –>
K+ and H+ are secreted
Which channel do Amiloride and Triamterene block?
Block the apical Na channel and decrease Na reabsorption
How do spironolactone and eplerenone work?
Compete with aldosterone for binding to intracellular receptors (cytoplasmic receptors)
- cause decreased synthesis of protein which activates Na+ channel
- decreased numbers of Na+/K+ ATPase pumps in the basolateral membrane
Canrenone?
Spironolactone is metabolised to canrenone which accounts for most of the action of the drug
How are spironolactone and eplerenone absorbed?
Absorbed from the GI tract
Triamterene and Amiloride and GI absorption?
Triamterene is absorbed well
Absorption of amiloride is poor
…used in the treatment of:
Heart failure
Primary hyperaldosteronism (Conn’s syndrome)
Resistant essential hypertension
Secondary hyperaldosteronism (due to hepatic cirrhosis with ascites)
Aldosterone antagonists
Why can loop/thiazide diuretics cause alkalosis?
Cause excretion of H+
How does aldosterone work?
1) Increases synthesis of Na+/K+ ATPase
2) Increases synthesis of a protein that activates the epithelial Na+ channel (ENAc)
Why do you give mannitol IV?
because it is membrane impermeable
