Thiazide diuretics

A short review by Dr. SWARUPA RANI KASUKURTHI
YOUTUBE LINK FOR AUDIO AND VIDEO-https://youtu.be/POGOwzfEpGs

1. THIAZIDE DIURETICS

2. INTRODUCTION Medium Ceiling diuretics THIAZIDE DIURETICS Moderate efficacy diuretics

3. Thiazide diuretics Tablet (mg) Chlorothiazide 500-1000mg/day Hydrochlorothiazide 12.5 -25 mg/day Bendroflumethiazide 2.5 - 5 mg /day Methyclothiazide 2.5 - 5mg /day Thiazide like diuretics Tablet (mg) Chlorthalidone 25-100 mg /day Metolazone 2.5 – 10 mg / day Indapamide 2.5 - 10 mg /day HTN Hypoparathyroidism Enhances action of furosemide

4. MECHANISM OF ACTION Cl- Na+ Cl- symporter Na+ Cl- Na+ k+ ATPase pump Cl- channel Na+ DCT Epithelial cell Thiazide PCT + H2O

5. MECHANISM OF ACTION Inhibit reabsorption of Na+ and Cl- in the DCT which results in water retention. Thiazide diuretics also decreases Ca+2 content of urine by promoting reabsorption of Ca+2

6. PHARMACOKINETICS Rapid GI absorption Distribution in extracellular space Elimination unchanged in kidney PHARMACODYNAMICS Inhibit reabsorption of Na+ and Cl- Cotransporter. Promoting reabsorption of Ca+2 Variable elimination kinetics

7. CLINICAL USES Oedema Hypertension & reduce cardiovascular events in hypertensive patients. Nephrolithiasis (calcium oxalate) Osteoporosis

8. CLINICAL USES - MNEMONIC C H I C k E n CHF HTN Ca+ Oxalate stones INSPIDUS EDEMA OSTEOPOROSIS

9. THIAZIDE DIURETICS ADVERSE EFFECTS HYPERGLYCEMIA HYPERURICEMIA HYPERLIPIDEMIA HYPERCALCEMIA HYPONATREMIA HYPOKALEMIA HYPOMAGNESEMIA HYPOCHLOREMIC ALKALOSIS

10. ADVERSE EFFECTS - MNEMONICS HYPERGLUC o S e HYPO MONK HYPER = Increased G = Glycemia L = Lipidemia U = Uricemia C = Calcemia HYPO = Decreased M = Magnesemia O = Chl o remic Alkal o sis N = Natremia K = Kalemia s = Sexual dysfunction

11. DRUG INTERACTIONS Thiazide diuretics reduces the effect of oral anticoagulants , sulphonylureas and insulin. Enhances the effect of diazoxide , digoxin , lithium , loop diuretics and vitamin D. Probenecid blocks the action of thiazides . Quinidine induced torsade de pointes (usually self limiting) may be converted to life threatening ventricular fibrillation due to hypokalemia produced by thiazides. Increases toxicity of Lithium.

12. PRECAUTIONS AND CONTRAINDICATIONS Thiazides are chemically sulphonamides and shows CROSS REACTIVITY , contraindicated in patients allergic to sulphonamides Severe renal impairment Severe hepatic impairment Addison disease Hypersensitivity Pregnancy & Lactation C/I :