1.  Prazosin, doxazosin, and terazosin  They causing relaxation of both arterial and venous smooth muscle. Postural hypotension may occur in some individuals. Reflex tachycardia and first-dose syncope are almost universal adverse effects. Tamsulosin, an α 1 -blocker has been used in the treatment of benign prostatic hyperplasia.

3.  Labetalol and carvedilol block α 1, β 1, and β 2 receptors. Carvedilol, although an effective antihypertensive, is mainly used in the treatment of heart failure.

4. CENTRALLY ACTING ADRENERGIC DRUGS Clonidine This α 2 -agonist diminishes the central adrenergic outflow, used primarily for the treatment of hypertension that has not responded adequately to treatment with two or more drugs. Clonidine does not decrease renal blood flow or glomerular filtration and, therefore, is useful in the treatment of hypertension complicated by renal disease. It is given orally and excreted by kidneys and may induce water and sodium retention Adverse effects: sedation, dry mouth, and constipation. Rebound hypertension occurs following abrupt withdrawal of clonidine.

5. ALPHA - M ETHYLDOPA It is an α 2 -agonist which converted to methyl norepinephrine centrally to diminish adrenergic outflow from the CNS. It has been used in hypertensive pregnant patients. Side effect: Sedation; dry mouth; impotence; +ve Coomb’s test (hemolytic anemia, leucopenia, thrombocytopenia gynecomastia due to dopaminergic suppression of prolactin secretion……how?, hepatitis, nausea and constipation “false neurotransmitter”

6. * They are direct-acting smooth muscle relaxants by activation of the potassium channels, increasing potassium efflux and inducing hyper polarization of the smooth muscle membrane. * When the membrane is hyperpolarized, calcium influx is inhibited and the arteriolar smooth muscle relaxes. * They produce reflex stimulation of the heart (increased myocardial contractility, heart rate, and oxygen consumption. ) with the risk of angina pectoris, MI or HF. * Vasodilators also increase plasma renin concentration, resulting in sodium and water retention (so concomitant use of beta blockers or diuretics is necessary.

7. Hydralazine Hydralazine  It acts primarily on arteries and arterioles. This results in decreased peripheral resistance, which, in turn, prompts a reflex elevation in heart rate and cardiac output.  It used to treat moderately severe hypertension.  Hydralazine monotherapy is an accepted method for pregnancy-induced hypertension.  Side effects: headache, tachycardia, nausea, sweating, lupus like syndrome, arrhythmia, and precipitation of angina.

8. It is administered orally for treatment of severe to malignant hypertension that is refractory to other drugs. Reflex tachycardia and fluid retention may be severe and require the concomitant use of a loop diuretic and a β -blocker. This drug is used topically to treat male pattern baldness.

9. DIAZOXIDE  Relatively long-acting parenterally administered arteriolar dilator  The most significant toxicity from diazoxide has been excessive hypotension and provoke angina, salt and water retention.  Diazoxide inhibits insulin release from the pancreas (probably by opening potassium channels in the beta cell membrane) and is used to treat hypoglycemia secondary to insulinoma.

10. RESISTANT HYPERTENSION  It is defined as blood pressure that remains still elevated despite administration of an optimal three drug regimen that includes a diuretic.

11.  Race and age: For young (and white) patients, consider starting with an ACE inhibitor (A) or β-blocker (B). For older (and black) patients, consider stating on a calcium-channel blocker (C) or diuretic (D).  Pregnancy: 1. Avoid ACE inhibitors (teratogenic), ARBs, and aliskiren because these drugs may cause fetal injury or death. 2. Nitroprusside is contraindicated in the later stages of pregnancy due to possible fetal cyanide poisoning 3. labetalol is used to prevent maternal cerebrovascular complications in severe HT state. 4. The drug of choice is α-Methyldopa

12. HYPERTENSIVE EMERGENCY O It is rare but life-threatening situation in which the diastolic blood pressure is either greater than 150 mm Hg (with systolic blood pressure greater than 210 mm Hg) in an otherwise healthy person

13.  Sodium nitroprusside: I.V infusion  Labetalol  Fenoldopam: is a peripheral dopamine-1 receptor agonist that is given as an intravenous infusion. Unlike other parenteral antihypertensive agents, fenoldopam maintains or increases renal perfusion while lowering blood pressure. The diuretic action of fenoldopam is mainly caused by the increase in renal blood flow. The drug is contraindicated in patients with glaucoma.  Nicardipine: The major limitation is its long half-life (approximately 8 hours), which precludes rapid titration