Diuretics And Renal Pharmacology Flashcards
What are the functions of the kidney 0
• Regulatory
– Fluid balance
– Acid-base balance – Electrolyte Balance
• Excretory
– Waste products (protein metabolism) – Drug elimination
– Glomerular Filtration – Tubular Secretion
• Endocrine
– Renin
– Erythropoetin
– Prostaglandins – 1-alpha calcidol
• Metabolism – Vitamin D – Polypeptides • Insulin – Drugs • Morphine • paracetamol
What are drugs acting on the real tubules
- Carbonic anhydrase inhibitors • Osmotic Diuretics
- Loop Diuretics
- Thiazides
- Potassium sparing diuretics • Aldosterone antagonists
- ADH Antagonists
- NB: Diuresis – loss of water; Natriuresis – loss of sodium
Give an overview o mannitol
0
Give an overview ofloop diuretics
-
Gove an overview of thiazids
S
Give an overview fo amilorise and spironolactne
S
What are other substances with diuretic action
- Alcohol – inhibits ADH release
* Caffeine - ↑GFR and ↓ tubular Na+ reabsorption
Desribe ADH antagonists
- Lithium – diuretic but not natriuretic. Inhibits action of ADH - Can get hypernatremic
- Tolvaptan – ADH antagonist. Diuretic but not natriuretic. Used to treat hyponatraemia (& prevent cyst enlargement in APCKD)
What are the general adverse effects of diuretics
• Hypovolaemia & hypotension
– Activates RAAS
– Can lead to acute kidney injury
• Electrolyte Disturbance (Na+, K+, Mg2+, Ca2+)
• Metabolic Abnormalities (depends on individual drug) • Anaphylaxis / photosensivity rash etc (rare)
What ae common specific adrs o diuretics
Thiazides • Gout • Hyperglycaemia • Erectile dysfunction • ↑LDL↑TG • Hypercalcaemia
Spironolactone
• Hyperkalaemia
• Impotence
• Painful gynaecomastia
Frusemide
• Ototoxicity • Alkalosis
• ↑LDL ↑TG • Gout
Bumetanide
• Myalgia
Describe potential specific drug effects/interactions
Ss
What diuretics are used in htn
- Thiazide diuretics (vasodilatation as well as diuresis)
- Spironolactone
- (Loop diuretics)
- ACE inhibitors / Ang II antagonists
- b-blockers
What diuretics are used in hf
- Loop diuretics
- Spironolactone – non-diuretic benefits
- ACEInhibitors/AngIIantagonists • b-blockers
What diuretics are used in decmpesated liver disease
• Spironolactone • Loop diuretics
What are used in nephrotic syndrome
Nephrotic syndrome
https://www.flickr.com/photos/vicg/4695453355
• Loop diuretic (often big doses needed)
• +/- thiazides
• +/- potassium-sparing diuretic / potassium supplements
What ere used in ckd
- ↓GFR leads to salt and water retention • Loop diuretics
- (+/- thiazide-like)
- Alkalosis & kalliuretic effects potentially beneficial
- Generally avoid K+-sparing diuretics
Describe diuretic resistance
Furosemide bound. Albumin.absorbed form storm into blood stream needs to then get to pct. then needs to be moved to loop where it acs on NKCC2. If pump doesnt work - furosemide doesnt go around bldstream as wel. If you have cks. Es nephrons to less tubules for it to cross. Anion transporters have to try to do a lot more than normal - less furosemide across. Nephrotic - less protein for it to bind to to get across.
Can get ascites (oedema in gut?) - then they dont absorb as well - may have to give iv
Describe refractory oedema
- Check salt intake (24 hour sodium excretion if necessary)
- Give furosemide iv if gut oedema likely
- Find minimum effective dose
- Give repeated bolus or infusion (short t1/2)
Why are thiazides typically not good as diuretics
-
Give a overview as diuretic usage
Ss
What are potentially neurotoxicitydrugs
• Aminoglycosides: e.g: gentamicin • Vancomycin (intravenous only)
• Aciclovir
• NSAIDs
• ++ more
Worse if renal function is impaired Can cause irreversible renal damage esp acute
What are drugs that can cause problems it’s real dysfunction
- ACE-Inhibitors • Diuretics
- NSAIDs
- Metformin
How to acei and nsaids affect renal perfusion
Precipitous drop when environment is hostile - can tip someone from cusp of an into ful bow ski. I healthy, wont have much efect
Disease of the afferent arteriole (BP, renal artery stenosis, progressive kidney disease, DM) can result in too great or too little a response to these stimuli1
Describe prescribing in ckd
Avoid nephrotoxins. • If gentamicin / vancomycin required, dose very carefully in consultation with pharmacist. • Check with pharmacist – whether any of existing drugs need dose altering – Allopurinol – Digoxin – Cyclosporin / Tacrolimus – Low molecular weight heparins • Side effects of some common drugs are increased with renal disease (accumulation of metabolites) – Morphine & other opiates – Nitrofurantoin – Statins
What are the causes of hyperkalaemia
• Excess intake (virtually never the only cause)
• Movement out of cells
– Acidosis
– Hypertonicity
– Tissue (especially muscle) damage
• Reduced urine loss
– Reduced GFR
– Reduced distal delivery of Na+ (oliguric AKI, obstruction)
– Reduced secretion in collecting duct
• Drugs
– RAAS Inhibitors (ACE-Inhibitors, spironolactone), NSAIDs, ENaC blockers (trimethoprim, amiloride)
What are the effects of hyperkalaemia
Can cause life-threatening cardiac arrhythmias.
• Any ECG change is cause of immediate action.
ECG changes ss
What is the management or hyperkalaemia
• Identify cause! • ECG • Treatment: – 1. Protect the heart: – 2. Lower serum K+ – 3. Remove K+ from body (Sodium bicarbonate) (Salbutamol) Calcium gluconate Insulin / Dextrose Calcium resonium
