Diuretics & Renal Pharm Flashcards
What drugs act on the renal tubule?
Diuretics
What is an example of an osmotic diuretic?
Mannitol
How do osmotic diuretics work?
Build up in the lumen of the PCT and descending limb of LoH
Osmotic effect causes water to be pulled into the lumen => loss of water
What is a risk of using osmotic diuretics?
Hypernatraemia
What are some examples of loop diuretics?
Furosemide
Bumetanide
How do loop diuretics exert their effects?
Inhibition of NaKCC in the thick ascending limb
Na builds up in lumen => water builds up in lumen
What are some risks of loop diuretics?
Hypokalaemic metabolic alkalosis
Enhanced Na delivery to collecting duct => increased K loss
Hypocalcaemia
How do aldosterone antagonist diuretics exert their actions?
Inhibition of aldosterone => reduction in expression of ENaC and Na/K ATPase in the collecting duct
Reduced reabsorption of Na => increased water loss
What other substances have a diuretic action?
Alcohol - inhibits ADH release
Caffeine - increased GFR and decreased Na reabsorption
What are some drugs that act as ADH antagonists?
Lithium - diuretic (but not natriuretic), inhibits action of ADH
Tolvaptan - ADH antagonist, used to treat hyponatraemia
What are some generic adverse drug reactions of diuretics?
Hypovolaemia and hypotension - activation of RAAS => AKI
Electrolyte disturbance
Metabolic abnormalities
Anaphylaxis
What are some ADRs of thiazides?
Gout Hyperglycaemia Erectile dysfunction Increased LDL and TG Hypercalcaemia
What are some ADRs of spironolactone?
Hyperkalaemia
Impotence
Painful gynaecomastia
What are some ADRs of furosemide?
Ototoxicity
Alkalosis
Increased LDL and TG
Gout
What are some ADRs of bumetanide?
Myalgia
What is a potential consequence of interaction of ACE-i and K+ sparing diuretics?
Increased hyperkalaemia => cardiac problems
What are potential consequences of interactions between aminoglycosides and loop diuretics?
Ototoxicity
Nephrotoxicity
What is a potential consequence of interaction between digoxin and thiazide/loop diuretics?
Hypokalaemia => increased digoxin binding and toxicity
What are potential consequences of interactions between β-blockers and thiazide diuretics?
Hyperglycaemia
Hyperlipidaemia
Hyperuricaemia
What are some potential consequence of interactions between steroids and thiazide/loop diuretics?
Hypokalaemia
What are some potential consequence of interactions between lithium and thiazide/loop diuretics?
Lithium toxicity - thiazide
Reduced lithium levels - loop
What are some potential consequences of interaction between carbamazepine and thiazide diuretics?
Hyponatraemia
How are osmotic diuretics used?
Reduce high intracerebral pressure
What are loop diuretics used for?
Oedema
What are thiazide diuretics used for?
Hypertension
What are potassium sparing diuretics used for?
Low potassium when a diuretic is required
What are aldosterone antagonist diuretics used for?
Heart failure
Ascites
Hypertension
Hyperaldosteronism
What are ADH antagonists used for?
Hyponatraemia
What drugs are potentially nephrotoxic?
Aminoglycosides eg gentamicin
IV vancomycin
Aciclovir
NSAIDs
What drugs can cause problems with renal dysfunction?
ACE-i
Diuretics
NSAIDs
What is the effect of NSAIDs on renal perfusion?
Inhibits prostaglandins => unable to vasodilate afferent arteriole
Therefore unable to maintain GFR with reduced renal perfusion
What is the effects of ACE-i/ARB on renal perfusion?
Inhibits Angiotensin II or aldosterone
Therefore unable to vasoconstrict efferent arteriole
Unable to maintain GFR with reduced renal perfusion
How is hyperkalaemia managed?
Calcium gluconate - protects the heart
Insulin/dextrose - lowers serum K+ by activating Na/K ATPase
Calcium resonium - removes K+ from the body
