Diuretics Flashcards
How do Carbonic Anhydrase Inhibitors work?
Prevent Na+/HCO3- reabsorption.
When are carbonic anhydrase inhibitors used?
Glaucoma
What is the ADR of carbonic anhydrase inhibitors?
Metabolic acidosis
Name an Osmotic Diuretic and it’s route of administration
Mannitol, given intravenously
When are osmotic diuretics used?
Raised intra-cranial pressure.
What are contra-indications of osmotic diuretics?
Congestive heart failure and pulmonary oedema
How do osmotic diuretics work?
Enter the tubules and as they are non-reabsorbable, water uptake is decreased.
What are ADRs of osmotic diuretics?
Fever and chills
How do loop diuretics work?
Inhibits NKCC2 transporter at the thick ascending limb, reducing sodium and thus water reabsorption.
Name 3 loop diuretics
Furosemide, Torsemide, Bumetanide
What is a loop diuretic contraindication?
Severe renal impairment
What is the oral onset time of loop diuretics?
4-6 hour onset.
When are loop diuretics used?
Oliguria, hypertension pulmonary oedema and heart failure.
What are some ADRs of loop diuretics?
Hyponatraemia, hypokalaemia, hypovolaemia, hypotension, metabolic alkalosis, hyperuricaemia, ototoxicity (furosemide only) and myalgia (bumetanide only).
What are 3 DDIs of loop diuretics?
Hypokalaemia with either cardiac glycosides or steroids, and ototoxicty with gentamicin.
How do thiazide diuretics work?
Inhibit the Na/Cl co-transporter in the distal convoluted tubule, reducing sodium and subsequently water reabsorption.
What are some contraindications of thiazide diuretics?
Hypokalaemia, hyponatraemia and hypercalcaemia.
What are some ADRs of thiazide diuretics?
Hyporkalaemia, hyponatraemia, hypercalcaemia, hyperuricaemia, hypermagnesaemia, metabolic alkalosis and decreased glucose tolerance.
Name 2 thiazide diuretics
Bendroflumethiazide and Metolazone
Name 4 DDIs of thiazide diuretics
Increased hyponatraemia risk with carbamezipine, increased digoxin toxicity risk with digoxin, increased hypokalaemia risk with steroids, and increased hyperuricaemia and hyperglycaemia risk with beta-blockers.
Name 2 potassium sparing diuretics
Amiloride and spironolactone
How does amiloride work?
Blocks ENaC channels at the collecting ducts, reducing sodium and subsequently water intake.
How does spironolactone work?
It is an aldosterone antagonist, reducing sodium secretion and causing diuresis.
What are the two main ADRs of potassium sparing diuretics?
Hyperkalaemia and hyponatraemia.
What are 3 additional ADRs for spironolactone?
Gynaecomastia, menstural disorder and erectile dysfunction.
What is a DDI of potassium sparing diuretics?
ACE inhibitors, as it greatly increases the risk of hyperkalaemia.
Name 2 ADH Antagonists
Lithium and Demecocylcine
What effect does antagonising ADH have?
Reduces aquaporin-2 insertion into the cells of the collecting duct.
What 3 things can cause poor diuresis?
High salt/sodium intake, NSAID use (lowers renal perfusion), and volume depletion.
What 4 ECG changes indicate hyperkalaemia?
Tall tented T waves, prolonged PR interval, wide QRS complex and ST segment depression.
What is given to protect the heart in hyperkalaemia?
Intravenous calcium gluconate.
