Diuretics PDF

Diuretics Diuretics are drugs that decrease blood volume and increase urine volume. They work on nephrons and are divided into five groups: 1. Loop Diuretics: These work in the loop of Henle. 2. Thiazide Diuretics: They operate in the early part of the distal convoluted tubule (DCT). 3. Pot...

Diuretics Diuretics are drugs that decrease blood volume and increase urine volume. They work on nephrons and are divided into five groups: 1. Loop Diuretics: These work in the loop of Henle. 2. Thiazide Diuretics: They operate in the early part of the distal convoluted tubule (DCT). 3. Potassium-Sparing Diuretics: These act in the last part of the DCT. 4. Carbonic Anhydrase Inhibitors (CAI): work in the proximal convoluted tubule (PCT). 5. Osmotic Diuretics: These affect various parts of the nephron. Carbonic Anhydrase Inhibitors (CAI): 1. They are weak diuretics that increase the excretion of NaHCO₃, leading to: Metabolic acidosis Alkalinization of urine 2. They also increase the excretion of Na from the brain. 3. CAIs inhibit the formation of aqueous humor and are used for: Glaucoma Adjuvant therapy for epilepsy Idiopathic cranial hypertension Urine alkalinization Prevention of mountain sickness. SE of CAIs: 1. Metabolic acidosis 2. Steven-Johnson syndrome (hypersensitivity reaction) Examples of CAIs: 1. Acetazolamide (oral) 2. Dorzolamide (eye drops) Example: Mannitol (IV) Clinical Uses: o Increase intracranial pressure (ICP) o Increase intraocular pressure (IOP) SE of Osmotic Diuretics: 1. Hypotension 2. Hypo-hypernatremia 3. Diarrhoea 24 TYPE SITE MOA CLINICAL USE SIDE EFFECTS CI EXAMPLES Loop Ascending 1. Inhibit 1. Severe hypertension 1. Hypo: 1. Hypotension 1. Furosemide (O, P). diuretic part of the reabsorptio 2. Oedema of any cause a. Hypotension 2. DM 2. Torsemide (O, P). loop of n of water (pulmonary, CHF, renal, b. Hypokalemia 3. Gout 3. Bumetanide (O). The most Henle and or hepatic failure) c. Hypocalcemia 4. Hypocalcemia (the most commonly used in oral effective electrolytes 2. Hyper (occurs in 5. Hyperlipidemia preparation) group 2. ( chronic use) 6. Hypokalemia excretion of a. Hyperglycemia Na⁺/K⁺/2Cl⁻ b. Hyperuricemia /2Mg²⁺/Ca²⁺ c. Hyperlipidemia (by and water) unknown mechanism) 3. Dehydration 4. Ototoxicity = deafness (in chronic use or when given as IV infusion) Thiazide Early part Increase 1. Mild to moderate 1. Hyper: 1. Hypotension 1. Hydrochlorothiazide (O) (8-12 hrs) of DCT excretion hypertension a. Hyperglycemia 2. DM 2. Chlorothiazide (only P) Most of water and 2. Idiopathic b. Hyperlipidemia 3. Gout 3. Indapamide (O) commonly Na/Cl hypercalciuria c. Hyperuricemia 4. Hypocalcemia 4. Chlorthalidone (O) used 3. Diabetes insipidus d. Hypercalcemia 5. Hyperlipidemia - Has long duration (about 60 2. Hypo: hours). a. Hypotension - Most commonly used b. Hypokalemia K- Late part Aldosterone Alone without 1. Hormonal disturbance, 1. Renal failure All of them are used orally and has Sparing of DCT receptor combination are used for: mainly in males due to long duration of action. diuretic antagonist a. Hyperaldosteronism because they decrease decreased 1. Spironolactone: Aldosterone and mechanism b. Mild hypertension androgen receptors aldosterone androgen receptor inhibitor, so used Weak c. Androgen receptor leading to): 2. Hyperkalemia for: diuretics blocker: can be a. Gynecomastia - Hirsutism. used for hirsutism b. Infertility - Hyperaldosteronism in females 2. Hyperkalemia 2. Eplerenone: Selective aldosterone Incombination with loop 3. GIT disturbance blocker (for hyperaldosteronism). or thiazide diuretics to: 3. Amiloride: Weak diuretics a. Increase efficacy for (increase Na and Cl excretion), either hypertension or preferred for Liddle's syndrome or oedema in combination with other diuretics. b. Prevent K loss Note: Liddle's syndrome is a state of hypertension with hypokalemia.