利尿劑英文ppt課件-wenkub
2022-12-23 03:29:36 本頁面
【正文】 e effect ? initial hypotensive effects ?decrease in blood volume and therefore a decrease in cardiac output ? continued hypotensive effects ?Na+ excretion intercellular Na+ concentration Na+/Ca2+ exchange intercellular Ca2+ concentration sensitivity of blood vessel response to NA reduced peripheral vascular resistance caused by relaxation of arteriolar smooth muscle 34 Clinical Uses ? Edema ? mild and moderate cardiac edema (CHF) ? Hypertension ? either uses alone or in bination with other antihypertensive drugs ? Nephrolithiasis due to idiopathic hypercalciuria。 osteoporosis ? decrease Ca2+ in tubular fluid ? increase Ca2+ in plasma 35 Clinical Uses ? Diabetes insipidus ? Used for the palliation of nephrogenic and pituitary diabetes insipidus. ? Typical symptoms: polydipsia and polyuria ? mechanism phosphodiesterase cAMP ADH action the secretion of NaCl plasma osmotic pressure less thirsty and desire to drink water 36 Side effects ? Electrolyte disturbances ? hypokalemia, magnesium deficiency ? Hyperuricemia and induced gout ? increases absorption of uric acid and petes for the transport mechanism with uric acid ? Hyperglycemia and hyperlipidemia ? decrease glucose tolerance, reduce insulin secretion and glucose utilization, aggravates preexisting diabetes ? increases plasma concentrations of LDLcholesterol, triglyeride and total cholesterol 37 Side effects ? Hypovolemia ? over treatment, acute loss of excessive fluid leads to postural hypotension and dizziness ? Others ? photosensitive, thrombocytopenia, agranulocytosis ? Thiazides binding with quinidine can lead to polymorphic ventricular tachycardia 38 Classification of Diuretics ? High efficacy diuretics (loop diuretics) ? Moderate efficacy diuretics ? Low efficacy diuretics (K+sparing diuretics) 39 Low efficacy diuretics ? act in the late distal tubules and collecting tubule to inhibit Na+ reabsorption and K+ secretion ? These drugs reduce potassium secretion, so term as K+ retention diuretics or K+ sparing diuretics ? High efficacy and moderate efficacy diuretics increase K+ excretion, so term as K+ lossing diuretics ? Major use is in bination with other diuretics to reduce sodium reabsorption and prevent potassium loss in the tubule. 40 Spironolactone ? Mechanism of action ? aldosterone regulate Na+ reabsorption and K+ secretion at late distal tubules and collecting duct ? Spironolactone is a petitive antagonist to aldosterone ? bind with cytoplasmic aldosterone receptors ? promotes Na+ excretion ? blunt the K+ secretion 41 42 lumen apical membrane interstitial fluid Collecting tubule Basolateral membrane AIP: aldosteroneinduced protein。 ALD: aldosterone Triamterene amiloride spironolactone aldosterone 47 48 48 Carbonic
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