Diuretics Flashcards
What are the uses of diuretics? (6)
- treatment and control of systemic oedema
- management of localised oedema
- improve urine flow (acute renal failure)
- treat certain endocrinopathies
- Exercise induced pulmonary haemorrhage (horses)
- Hypertension (humans??)
What are the classes of diuretics?
- loop diuretics
- thiazidines
- potassium sparing
- carbonic anyhydrase inhibitors (CAI)
- osmotics
What are the pharmacokinetic properties of loop diuretics? (7)
- sulphonamide derivatives
- secreted into PCT
- act on ascending loop to inhibit Na/K/2Cl co transporter which results in loss of these ions along with water in urine
- POTENT!
- they will also increase renal PG which increase renal blood flow (systemic venodilator)
- rapid onset
- lasts 4-6 hours
Do loop diuretics have any side effects?
YES
- dehydration
- pre renal azotemia
- electrolyte disturbances
- ototoxicity when used with aminoglycosides
What are the pharmacokinetic properties of Thiazidines? (6)
- secreted into PCT
- act in DCT to block Na/Cl reabsorption causing loss of Na, H, Cl, Mg and K with water in urine.
- dependent on renal PG production as ineffective with low renal blood flow
- mild-moderate potency
- slower onset but longer lasting
- no vet license
How are thiazidines used?
- as an add on to furosemide (loop diuretic)
- in nephrotoxic diabetes insipidus
Do Thiazidines have any side effects?
YES
- dehydration
- pre renal azotemia
- electrolyte disturbances
- ototoxicity when used with aminoglycosides
- alkalosis
- insulin resistance
What are the pharmacokinetic properties of K sparing?
- inhibits Na/H exchanger which decreased K loss indirectly.
- spirinolactone and epterenae (SP???) are competitive aldosterone anatagonists
- weak
When are K sparing used?
- in combination is other diuretics to reduce hyperkalaemia
- for ascites due to hepatic diseases
What are the pharmacokinetic properties of CAIs? (2)
- secreted into PCT
- inhibit tubular production of H for Na/H exchanger leading to an increase in NAHCO3 and water (and K) excretion
What are CAIs used for?
- topically for glaucoma in cats and dogs
- weak diuretics systemically; not often used
Are there any side effects for CAIs?
YES
-acidosis
What are the pharmacokinetic properties of osmotic diuretics?
filtered and effective mainly in the PCT and loop
Mannitol is an osmotic diuretic. What would it be used for and why?
-pulmonary oedema/ increase ICP
-it moves fluid into plasma
(also topically for glaucoma but not common so dinnae fret)
Are there any side effects for osmotic diuretics?
NO: not according to me notes anyway.
