Treatment of Systemic Hypertension

Flashcards for Systemic Hypertension Treatment

Hypertension (HT)

Blood pressure equal to or greater than 140/90 mm Hg.

Diagnosis of Hypertension

Repeated measurements of BP, at least 2 readings on 2 different occasions.

Essential (Primary) HT

95% of cases, of unknown cause, potentially related to genetic, psychological, environmental, or dietary factors.

Secondary HT

5% of hypertension cases, with known causes such as renal, endocrinal issues, or drug-induced factors.

Drugs Used in Hypertension Treatment

Diuretics, Drugs decreasing sympathetic activity, Direct Vasodilators, Calcium Channel Blockers, Angiotensin Converting Enzyme Inhibitors

Mechanism of action of Diuretics in hypertension

Direct action reduces peripheral resistance, decreases blood volume and CO, and decreases Na in vessel wall .

Thiazide Diuretics

Hydrochlorothiazide, Chlorthalidone & Indapamide. Act mainly by decreasing TPR. Used in mild to moderate hypertension.

Loop Diuretics

Frusemide , Ethacrynic acid and Bumetanide Increase renal blood flow by decreasing renal vascular resistance, veno-dilator through PG pathway .Used in moderate to sever hypertension and in renal impairment.

Potassium Sparing Diuretics

Spironolactone, Amiloride and Triamterene, Eplerenone used in combination with other diuretics to avoid potassium depletion.

Centrally acting ( VMC)

 2 agonist as: Methyl dopa, imidazoline I-1 receptor agonists (Clonidine).

Ganglion blocking agents

Only trimetaphan.

Adrenergic neuron blockers

Guanethidine decreases release, reserpine decreases storage, alpha methyl dopa decreases synthesis

Mechanisms of action of Beta blockers in hypertension

Decrease myocardial contractility and COP, decrease renin secretion, decrease CNS sympathetic flow, Antagonize tachycardia

Arterial Vasodilators

Hydralazine, Minoxidil, Diazoxide, Fenoldopam.

Arterial and venous Vasodilators

Sodium nitroprusside

Hydralazine Mechanism of action

Direct arteriolar dilator by increasing c.GMP

Minoxidil Mechanism of action

Increase cGMP or open K channel

Diazoxide Mechanism of action

Increase cGMP –open K channel, decreases insulin release (open K channel in B cells)

Fenoldopam Mechanism of action

Act as agonist to D1 receptor leading to Arteriolar dilation

Mechanism of action of calcium channel blockers

Decreases voltage-dependent Ca channel (L type).

Calcium channel blockers that affect cardiac tissues more

Verapamil-Diltiazem. Affect cardiac tissues more than blood vessels and Cause decrease HR

Calcium channel blockers that affect blood vessels mainly

Nifedipine, Nitrendipine Affect blood vessels mainly and Cause increase HR

Angiotensin converting enzyme inhibitors (ACE inhibitors)

Captopril (active). Enalapril, ramipril, perindopril fosinopril (Pro drugs)

Action of ACE inhibitors

Decreases ACE, kininase II leading to decrease angiotensin II, increase bradykinin decreasing PR, aldosterone, sympathetic transmission.

Angiotensin receptor antagonists.

Losartan –Valsartan - Candesartan.

Mechanism of action of Angiotensin receptor antagonists

Competitive blocker of angiotensin R (AT1)