Hypertension Drugs

Hypertension Drugs

Mechanism of Action According to Classification

Diuretic: Its a hypertension drugs that reduce BP by increasing Na & H2O excretion. This causes decrease in extracellular volume and resulting decrease in cardiac output and renal blood flow.

Example: Hydrochlorothiazide, Furosamide.

Beta-Blocker: Its a hypertension drugs that reduce Blood pressure (BP) by decreasing cardiac output. It also decreases sympathetic outflow from central nervous system and inhibit release of rennin from the kidney, thus decreasing formation of angiotensin II and secretion of aldosterone.

These drugs also reduce oxygen demand by reducing force and contraction of heart. So, decrease activity of heart, decrease cardiac output and fall BP.

Example: Propanolol, Atenololo.

                                          

Angiotensin Converting Enzyme (Ace) Inhibitor: Its a hypertension drugs that decrease blood pressure by reducing peripheral vascular resistance, except increasing cardiac output, rate or contractility. It blocks the angiotensin converting enzyme (ACE) that cleaves angiotensin I to form potent vasoconstrictor angiotensin II. So, vasodilatation occurs and bradykinin increase. It also decrease the secretion of aldosterone.

Example: Captopril, Ramipril.

Calcium Channel blockers: Calcium play an important role in maintaining the tone of smooth muscle and in contraction of myocardium.Calcium channel blockers are the hypertension drugs that block the inward movement of calcium (to cell) by binding to L-type calcium channel in the heart and in smooth muscle of coronary and peripheral vasculature. These cause the vascular smooth muscle to relax and dilating arterioles.

Example: Verapamil (1^st choise for Anti-arrythmic), Diltiazem (1^st choise for Anti-anginal), Nifedipine (1^st choise for Anti-hypertensive).

Alpha-Blocker: Its a hypertension drugs that decrease the peripheral vascular resistance and lower the arterial BP by causing the relaxation of arterial and venous smooth muscle. Salt & H2O retention occur.

It also blocks the post synaptic alpha adrenergic receptor. So, it inhibits the vasoconstriction produced by the norepinephrin that is released from the synaptic nerve endings. So, vasodilation occurs and lowers the blood pressure.

Example: Doxazosin, Prazosin.

Central Sympatholytics: Its a hypertension drugs that forms false neurotransmitter alpha-methyl nor-adrenaline which combines with alpha-receptor present on the surface of the neurons in the lower brain stems. So, inhibits neurons and decrease central and peripheral sympathetic activities. And finally, decrease blood pressure.

Example: Methyl dopa.

Direct vasodilator: Its a hypertension drugs that dilate resistant vessel, arteriolar dilation occur, decrease peripheral resistance and as a result decrease blood pressure.

Example: Diazoxide.

# Side Effects of Antihypertensive Drug

# Hypertension & its Cause

# Sign and Symptoms of Hypertension