Diuretics - Stuff You

Must Know...Dr Vivek BaligaConsultant Internal Medicine

http://heartsense.in/drvivekbaliga

Class of

Diuretic

Name of Diuretic

Mechanism of action

Site of action on nephron

Carbonic anhydrase inhibitors

Acetazolamide Carbonic Anhydrase inhibition

Proximal Convoluted tubule

Loop diuretics

Frusemide, Bumetanide, Torsemide, Ethacrynic acid

Inhibit Na-K ATPase

Ascending loop of Henle

Thiazide diuretics

Hydrochlorthiazide, Bendrofluazide

⊖ NaCl reabsorption↑ Calcium reabsorption

Distal convoluted tubule

Osmotic diuretics

Mannitol Osmotic Proximal convoluted tubule, descending loop of Henle

Class of

Diuretic

Name of Diuretic

Mechanism of action

Site of action on nephron

Potassium sparing diuretics

Spironolactone, Epleronone, Amiloride

Competitive antagonist of aldosterone

Collecting tubule

Class of

Diuretic

Name of Diuretic

Mechanism of action

Site of action on nephron

Sites of action of different diuretics

Loop Diuretics - Side EffectsHypokalemic metabolic alkalosisOtotoxicity - dose related reversible hearing

lossHyperuricemia - Hypovolemia causes increased

uric acid reabsortption in the proximal tubule precipitating gout

HypomagnesemiaAllergic reactions - skin rash, eosinophilia,

rarely interstitial nephritis - resolves with drug withdrawal

Dehydration

Thiazide Diuretics - Side EffectsHypokalemic metabolic alkalosisHyponatremiaHyperglycemia

Secondary to impaired glucose toleranceImpaired pancreatic release of insulinDecreased glucose utilisation by tissues

Thiazide Diuretics - Side EffectsHyperlipidemia

Elevated cholesterol levelsIncreased LDL levelsChanges could be transient and can

return to normal after long term therapy

Allergy - rareImpotence - likely secondary to volume

depletion

Carbonic Anhydrase InhibitorsIncludes Acetazolamide and Dorzolamide Acetazolamide has systemic uses, while

dorzolamide has topical uses (in glaucoma).

Mechanism of actionActs on proximal convoluted tubuleBlocks bicarbonate absorption - results

in hyperchloremic metabolic acidosis

Carbonic Anhydrase Inhibitors - Side EffectsHyperchloremic metabolic acidosisNephrolithiasisRenal potassium wastingHypersensitivity

AVOID in hepatic cirrhosis as it can precipitate encephalopathy.

Carbonic Anhydrase Inhibitors - UsesGlaucomaMetabolic alkalosisUrinary alkalinizationAcute mountain sicknessSome forms of epilepsyHypokalemic periodic paralysisSevere hyperphosphatemia

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