Unit 4 - Diuretics Flashcards

Question

How do loop diuretics cause hyperuricemia?

Answer 1

Can precipitate attacks of gout | - hypovolemiea associated enhancement of uric acid reabsorption in proximal tubule

Answer 2

Chronic use of loop agents | Hypomagnesemia - more common in patients with dietary magnesium deficiency

Answer 3

Loop diuretics are sulphonamides (except ethacrynic acid) - skin rash - eosinophilia - interstitial nephritis

Answer 4

Inhibit NaCl transport in the distal convoluted tube (not proximal)

Answer 5

Hydrochlorothiazide

Answer 6

All can be administered orally | - all secreted by the organic acid secretory system in the proximal tubule and compete with the secretion of uric acid

Answer 7

Block NaCl reabsorption from the luminal side of epithelial cells in the distal convoluted tubule - unlike loop diuretics which inhibit Ca2+ reabsorption in the thick ascending limb, thiazides enhance Ca2+ reabsorption - don't cause hypercalcaemia but they can mask it - action partly depends on renal prostaglandin production and therefore can be inhibited in certain conditions by NSAIDs

Answer 8

Hypertension Heart failure Nephrolithiasis due to idiopathic hypercalciuria - causing stones Nephrogenic diabetes insipidus - improper response to ADH - reduces ability of kidney to concentrate urine by removing free water Nephrogenic diabetes insipidus is caused by an improper response of the kidney to ADH, leading to a decrease in the ability of the kidney to concentrate the urine by removing free water

Answer 9

``` Hypokalaemic metabolic alkalosis Increased hyperuricemia Impaired carbohydrate tolerance Hyperlipidemia Hyponatremia Allergies and other reactions ```

Answer 10

Similar to loop diuretics

Answer 11

Hyperglycaemia can occur in those who are overtly diabetic or have mildly impaired glucose tolerance. Impaired insulin release and diminished tissue utilisation of glucose

Answer 12

Hypokalaemic metabolic alkalosis & increased hyperuricemia - similar to loop diuretics Impaired carbohydrate tolerance - hyperglycaemia can occur in those who are overtly diabetic or have mildly impaired glucose tolerance. Impaired insulin release and diminished tissue utilisation of glucose Hyperlipdemia - 5 - 15% increase in total serum cholesterol Hyponatremia - hypovolemia induced elevation of ADH, reduction in the diluting capacity of kidneys and increased thirst Allergic and other reactions - similar to loop diuretics. Serious allergic reactions are rare. Ototoxicity - more common in diminished renal function and receiving other ototoxic e.g. ahminoglycosides Hypomagnesemia - more common in patients with dietary magnesium deficiency

Answer 13

Prevent potassium secretion by antagonising the effects of aldosterone in collecting tubules Direct antagonism of mineralocorticoid receptors - spironolactone, eplerenone Inhibition of sodium influx via ion channel on the luminal membrane - amiloride, triamterene

Answer 14

Spironolactone | Eplerenone

Answer 15

Spironolactone - substantial inactivation by the liver - slow onset of action - several days for full therapeutic effect Eplenerone - spironolactone analogue with greater selectivity for mineralcorticoid receptor - several hundred fold less active on androgen and progesterone receptors

Answer 16

Reduce absorption of Na+ in the collecting tubule and ducts - potassium absorption and secretion at this site regulated by aldosterone - spironolactone and eplerenone bind to mineralocorticoid receptors and blunt aldosterone activity - amiloride and triamterene directly interfere with Na+ entry through the epithelial Na+ channels - action partly depends on renal prostaglandin production and therefore can be inhibited in certain conditions by NSAIDs

Answer 17

Most useful in states of mineralocorticoid excess or hyperaldosteronism - primary hypersecretion - Conn's syndrome - ectopic adrenocorticotropic hormone production - secondary hyperaldosteronism induced by heart failure, hepatic cirrhosis, nephrotic syndrome - thiazide or loop diuretics can cause secondary hyperaldosteronism

Answer 18

``` Hyperkalaemia Hyperchloremic Metabolic Acidosis Gynecomastia Impotence Benign prostatic hyperplasia (with spironolactone) ```

Answer 19

Hyperkalemia - Exacerbated by renal disease - maximum potassium secretion is reduced Concomittant use of drugs that reduce/inhibit renin or angiotensin II activity Potassium sparing!! Hyperchloremic Metabolic Acidosis - inhibition of H+ secretion in parallel with K+ secretion Gynecomastia, impotence, and benign prostatic hyperplasia with spironolactone

Answer 20

+ = increase - = decrease ``` Carbonic anhydrase inhibitors: NaCl + NaHCO3 +++ K+. + Body PH - acidosis ``` ``` Loop Agents: NaCl ++++ NaHCO3 0 K+. + Body PH - Alkalosis ``` ``` Thiazides: NaCl ++ NaHCO3 + K+. + Body PH - Alkalosis ``` ``` Loop Agents + Thiazide NaCl +++++ NaHCO3 + K+. ++ Body PH - Alkalosis ``` ``` K+ Sparing agents NaCl + NaHCO3 (+) K+. - Body PH - acidosis ```