Diuretics Flashcards
Complications of acetazolamide
Metabolic acidosis
Hypokalaemia
MoA of acetazolamide
Carbonic anhydrase inhibitor
Uses of acetazolamide
Topical for glaucoma
Uses of mannitol
Severe cerebral or pulmonary oedema
Complications of mannitol use
Excessive H20 loss and hypernatraemia
MoA of mannitol
Osmotic diuretic
Examples of ADH antagonists and their MoA
Lithium, demeclocycline
Decrease the concentrating ability of the collecting ducts in kidneys to increase H20 excretion in urine
Drug interactions with loop diuretics
Digoxin/steroids - hypokalaemia
Aminoglycosides - ototoxic and nephrotoxic
Drug interactions with thiazides
Digoxin/steroids - hypokalaemia
Beta blockers - hyperglycaemia/lipidaemia/uricaemia
Contraindications for thiazides
Gout
Effect of increasing bendroflumethiazide dose on BP
With increasing dose:
First large drop in BP
Decrease in BP becomes smaller and smaller
Drug interactions with amiloride and spironolactone
ACEi - hyperkalaemia
Side effects of diuretics in general
Electrolyte disturbance
Hypovolaemia
Hypotension
Rash
Side effects of thiazides
Gout
Erectile dysfunction
Side effects of spironolactone
Gynaecomastia
Side effects of bumetanide
Myalgia
Reasons for resistance to diuretic therapy
Not treating underlying cause
High salt intake
Non compliance
Poor gut absorption
NSAIDs (vasoconstrict afferent arteriole of glomerulus so decreases GFR)
Volume depletion (decreases filtration of diuretics)
High aldosterone (increases Na reabsorption)
3 main indications for diuretics
Heart failure
Hypertension
Decompensated liver disease
Why do drugs need altering in renal disease
Can accumulate to toxic levels
Drugs can be nephrotoxic
Principles for prescribing in CKD
Avoid nephrotoxins
Decrease dosages in line with GFR
Monitor renal function
Principles for prescribing in elderly
Renal function overestimated due to low creatinine (small muscle mass)
Need to start with low dose and titrate up slowly
