Affecting Urine Flashcards
Potassium sparing diuretics
Spironolactone (Aldosterone ant)
Amiloride (Na+)
Triamterene (Na+)
Potassium sparing diuretics - Na+ channel blockers
Block sodium reabsorption by principal cells in the late distal tubule and collecting duct. This reduces the potential and k+ secretion. Also reduces H+ secretion
Potassium sparing diuretics - Aldosterone antagonist
Competitive antagonist at aldosterone receptor. This reduces Na+ reabsorption and therefore K+ and H+ secretion
Potassium sparing diuretics - indication
HF/HTN - with thiazides or loop
Kidney disease
Hepati cirrhosis with ascites/oedema
Spironolactone - hyperaldosteronism (primary-conns) or (secondary- CHF, LIVER DISEASE, NEPHROTIC SYNDROME)
Potassium sparing diuretics - Adverse/Contraindication
Interact -
ACE inhibitors
Adverse-
Hyperkalaemia risk increased
Hyponatremia
Aldosterone inhibitiors -
Gynocomastia
Menstrual disorder
Male sexual dysfunction
Thiazide Diuretics
Bendroflumethiazide
Metolazone
Chlortalidone
Inapamide
Thiazide Diuretics - MOA
Act on the early distal tubule
Inhibit Na+/Cl- co-transporter. This increase the secretion of H+ and K+ into the collecting ducts. Decrease Ca2+ exretion
Thiazide Diuretics - Indications
HTN
Oedema 2nd to CHF/Liver disease/ Nephrotic
Prophylaxis of calcium containing stones
Thiazide Diuretics - SE
hypokalaemia hyponatremia hypercalcemia metabolic alkalosis Caution: Cardiac glycosides DM - may cause hyperglycaemia
Osmotic Diuretics
Mannitol
Osmotic Diuretics - MOA
Act on proximal tubule/descending LOH/ Collecting ducts
(water permeable parts)
Freely filtered in glomerulus and not reabsorbed. Water reabsorption is reduced because of presence of solute
Osmotic Diuretics - indications
raised intracranial pressure or (intraocular)
Osmotic Diuretics - contraindications
CCF/ Pulmonary Oedema –> can increase blood volume
Adverse-
Chills and Fever
Alpha Blockers -
prazosin
doxazosin
Alpha Blockers - MOA
Relax the smooth muscle at the urethra and opening of the bladder.
Helps flow.
Alpha Blockers - SE
Vasodilators in cardiac disease so can increase risk of hypotension
Parasympathomimetics
bethanechol
Parasympathomimetics - MOA
Increase detrusor muscle activity
Helpful in bladder outlet obstruction but no relief for acute urinary retention.
Parasympathomimetics - SE
Sweating
Bradycardia
Catheters used more now
Mirabegron
relaxes detrusor by activating b3 receptor
used in treatment of overactive bladder
stops urgent, frequent and uncontrolled urination
Antiandrogens -
Finasteride
5alpha reductase inhibitor. inhibits conversion of testosterone to dihydrotestosterone = reduced size of prostate and better urinary flow
Tamsulosin - alpha blocker
Difficulty in beginning the flow of urine, weak stream, and the need to urinate often or urgently (including during the middle of the night)
avoid in HTN
Antimuscarinics
Oxybutanin
Used in urge incontinence, frequency, urgency
Relaxation of detrusor muscle
Loop Diuretics -
Furosemide, bumetanide, torsemide
Loop Diuretics - MOA
Act on thick ascending branch of LOH
Inhibit Na+/K+/Cl- cotransporter in the luminal membrane. increased Na+ and Cl- excretionResults in increased sodium reaching the collecting duct and therefore increases K+ and H+ secretion
Inhibits Ca2+ and Mg reabsorption reduced (reduced membrane potential)
causes venodilation therefore relief before diuresis
Loop Diuretics - Indications
Pulmonary oedema
oliguria due to AKI
Resistant CHF and HTN
Loop Diuretics - Contraindications
severe renal impairment
Caution;
- cardiac glycosides (hypokalaemia increases effect and increases chance of arrhythmias)
- interact with amino glycoside antibiotics
