Vasomotor center I. Basic pharmacology Guanabenz aniane f antihypertension Sympathetic nerve terminals drugs Guanethid ne Resery etic gangla other B-blockers Angiotensina-Receptors of vessels Vascular sme captors of vessels Prazosin and Hydralazine Verapamil and other Losartan and other r blockers Minoxidil calcium channel Nitre receptor backers Diazoxide Fe B-Receptors of juxtaglomerular Kidney tubules Thiazides 29 Aliskiren Captopril and
I Basic pharmacology of antihypertension agents 1. Diuretics; depleting the sodium and reducing blood volume and perhaps by other mechanisms 2. Sympathoplegic agents: reducing peripheral vascular resistance, inhibiting cardic output, increasing venous pooling. 3. Direct vasodilators: relaxing vacular smooth muscle dilaing resistance vessels and/or increasing capacitance. 4. Agents that block RAAS: reduce peripheral vacular resistance and blood volume
depleting the sodium and reducing blood volume and perhaps by other mechanisms
l. Diuretics(利尿药) Sodium restriction is very preventive in the control of blood pressure. It is a nontoxic and therapeutic measure. 1) Pharmacological roles (1) Diuretic action: In the early stage: reducing blood volume and cardiac output; In the late stage: reduce peripheral vascular resistance(by reducing the Nat; reduce Nat-Ca2+ exchange in vascular smooth muscle cells(Ca2+i \, peripheral resistance l (2) Non diurectic action: direct vasodilating, e.g. Indapamide a non -thiazide sulfonamide diuretic with both diuretic and vasodilator activity; Amiloride inhibits smooth muscle responses to contractile stimuli
§ Sodium restriction is very preventive in the control of blood pressure. It is a nontoxic and therapeutic measure. 1) Pharmacological roles (1) Diurectic action: In the early stage: reducing blood volume and cardiac output; In the late stage: reduce peripheral vascular resistance (by reducing the Na +; reduce Na +-Ca 2+ exchange in vascular smooth muscle cells (Ca 2+i , peripheral resistance ) (2) Non diurectic action: direct vasodilating, e.g. Indapamide, a non-thiazide sullfonamide diuretic with both diuretic and vasodilator activity; Amiloride inhibits smooth muscle responses to contractile stimuli. （利尿药）
1. Diuretics Selection of diuretics arteriole Distal tubule Loop Diuretics Normally used in severe hypertension, in renal arteriole insufficiency and in cardiac failure or cirrhosis capsule tubule Thiazides and related diuretics Descending Normally used in mild or moderate nb of oop of hypertension with normal renal and cardiac Henle function Collecting Potassium-Sparing Diuretics Useful to avoid excessive potassium depletion. Ascending limb of loop of Henle Carbonic Anhydrase Inhibitors Loop of Henle Osmotic diuretics Be careful increase blood pressure Nephron, a functional unit of kidney
Selection of diuretcs Nephron, a functional unit of kidney Normally used in severe hypertension, in renal insufficiency and in cardiac failure or cirrhosis. Normally used in mild or moderate hypertension with normal renal and cardiac function. Useful to avoid excessive potassium depletion. Be careful increase blood pressure
1. Diuretics 2)Clinical application: diuretics alone for mild or moderate essential hypertension. Combine with sympathoplegic and vasodilator drugs to control the tendency toward sodium retention caused by these agents. Dosing considerations(thiazide vs. Furosemide) 100-200 mg thiazide diuretics are more natriuretic but the same effect of anti-hypertension is the same as 25-50 mg thiazide diuretcs A threshold amount of body sodium depletion may be sufficient for anti-hypertensive efficacy. The blood pressure response to loop diuretics continues to increase at doses many times greater than the usual therapeutic dose
Dosing considerations (thiazide vs. Furosemide) 100 - 200 mg thiazide diuretics are more natriurectic but the same effect of anti-hypertension is the same as 25 – 50 mg thiazide diuretcs. A threshold amount of body sodium depletion may be sufficient for anti-hypertensive efficacy. The blood pressure response to loop diuretics continues to increase at doses many times greater than the usual therapeutic dose. 2) Clinical application: diuretics alone for mild or moderate essential hypertension. Combine with sympathoplegic and vasodilator drugs to control the tendency toward sodium retention caused by these agents