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Urogenital Pharmacology - Coggle Diagram
Urogenital Pharmacology
Thiazide diuretics
Prevent Na reabsorption in the DT and ascending loop by inhibition of NaCl co-transporter (so more Na and water are excreted
Example: Bendroflumethiazide 2.5mg, chlorthalidone 12.5-25mg, indapamide 2.5mg
Onset of action is within 1-2 hours and duration of action varies from 12-18 hours to 48-72 hours
Can take 2-3 weeks to lower BP
Avoid if eGFR ≤ 30mL/min/1.73m2
Acutely, they can cause diuresis, and chronically they can lower peripheral resistance
Side effects: hypercalcaemia, hyperglycaemia, hyperuricaemia, hyponatraemia, lipid abnormalities, K depletion, volume depletion, and hypersensitivities
Indication: hypertension, reduced peripheral vascular resistance, HF, hypercalciuria, and diabetes insipidus
Contraindications: Addison's disease, hypercalcaemia, hyponatraemia, hypokalaemia, and symptoatic hyperuricaemia
They are ineffective in advanced CKD (GFR <30) as less sodium being delivered to the distal tubule and therefore less thiazide diuretic action in the distal tubule
Thiazide-like diuretics
MOA: same as thiazides (structurally different)
Chlortalidone: similar to hydrochlorothiazide but longer duration
Metolazone: more potent and will cause sodium excretion in advanced renal failure
Indapamide: long duration action; excreted via GI tract as well as renal and so less likely to accumulate in renal failure
Loop diuretics
Inhibit the Na K Cl transporter in the ascending loop of Henle
Cause increased renal blood flow and decreased renal vascular resistance
Example: furosemide
Often used in combination with potassium sparing diuretic
Side effects: hyponatraemia, hyperuricaemia, acute hypovolaemia, K depletion, hypomagnesaemia, and metabolic alkalosis
Indications: HF, pulmonary oedema, hypercalcaemia, and hyperkalaemia
They have a rapid onset of action
Contraindication: anuria, severe hypokalaemia/hyponatraemia, and renal failure 9from nephrotoxic/hepatotoxic drugs)
Potassium-sparing diuretics
Act on collecting tubule
Used in combination with other diuretics
Don't deplete K
Indications: HF, and secondary hyperaldosteronism
Side effects: leg cramps, increased blood uric acid, and K retention
Spironolactone has gastric effects and mimics sex steroids (causing gynaecomastia and menstrual irregularities etc)
Aldosterone antagonists
Indication: moderate-severe HF
Example: spironolactone and eplereone
They retain K so careful monitoring is required
MOA: bind to aldosterone receptor. Inhibition of aldosterone results in K retention and Na excretion
Sodium channel blockers
Examples: triamterene and amlioride
Side effects: hyperkalaemia (in patients with renal impairment), GI effects, kidney stones, metabolic acidosis, and rashes
MOA: inhibits Na channels and prevents Na reabsorption which results in K retention and Na excretion
Carbonic anhydrase inhibitor
Not a potent diuretic
Example: acetazolamide
MOA: inhibits carbonic anhydrase on apical membrane of PT which influences CO2 transport in blood
Indications: glaucoma and mountain sickness (prophylaxis)
Side effects: metabolism acidosis (mild) and K depletion
Contraindications: adrenocortical insufficiency, acidosis, hypokalaemia, and hyponatraemia
Osmotic diuretics
Example: mannitol
Side effects: extracellular water expansion and dehydration
Indications: intracranial pressure and acute renal failure
Contraindications
Inhaled route: impaired lung function and bronchial hyper-responsiveness
IV route - anuria, severe cardiac failure, intracranial bleeding, severe dehydration, and severe pulmonary oedema
MOA: water excreted by osmotic effect (filtered and inhibited reabsorbed)
Not useful to treat Na retention
Alpha blockers
Specific for alpha-1a receptor
Cause a relaxation in the vascular smooth muscle around the bladder and urethra
Examples: tamsulosin, doxazosin, and alfuzosin
Side effects: dizziness, hypotension, and retrograde ejaculation
Cautions: must take care with initial dose, the elderly, cataract surgery, and concomitant antihypertensives
Contraindications: history of micturition, syncope, or postural hypotension
5-alpha reductase inhibitors
Decreases production of dihydrotestosterone
Examples: finasteride and dutasteride
Side effects: impotencce, ED, and breast tenderness
Indications: treatment for BPH and hair loss
Contraindication: obstructive uropathy
Anti-muscarinics
Block M3 receptors
Examples: solifenacin and oxybutynin
Side effects: GI discomfort, cystitis, dry eyes, and dry throat
Indications: overactive bladder and urgency/nocturia associated with BPH
Contraindication: glaucoma