Hypertension Definition Hypertension is the blood pressure elevated

Hypertension

Definition. Hypertension is: the blood pressure elevated enough to perfuse Tissues and organs. High systemic blood pressure is usually defined as 1 - a systolic reading ≥ 140 mm Hg. 2 - a diastolic reading ≥ 90 mm Hg (≥ 140/90). Factors control blood pressure: 1 - Cardiac out put 2 - Peripheral resistance 3 - Viscosity of blood

Physiology: What cause hypertension : 1 - Sympathetic nervous system may be responsible for hypertension if it. Increase the cardiac output. Increase the heart rate. Increase the total peripheral vascular resistance (TPR). 2 - Renin-angiotensin-aldosterone system: Renin (an enzyme from kidney) reacts to produce angiotensin which is a protein whose presence in the blood tends to raise blood pressure. 3 - Angiotensin converting enzyme (ACE)which is able to convert angiotensin I to form angiotensin II which tend to vasoconstriction increase Na and water retentions

Complications of hypertension. Cardiac effects: Heart failure Cerebral(CNS) effects: Decreased blood flow, decreased oxygen supply, and weakened blood vessel walls lead to memory deficits, and the development of aneurysms with hemorrhage. Renal effects: Renal failure.

Treatment Diuretics. Vasodilators (direct acting). Angiotensin -converting enzyme (ACE) inhibitors. Angiotensin receptor antagonists. β-Adrenergic blocking agents. Centrally acting α-agonists. Calcium-channel blockers. Diuretics Thiazide diuretics (Hydrochlorothiazide) Loop diuretics (Furosemide). Potassium-sparing diuretics(Amiloride).

Diuretics side effects Thiazide diuretics Loop diuretics (Hydrachlorothiziad ) Furosemide Low Potassium K+ (Hypokalemia ) Low Potassium ion (K+ ) (Hypokalemia ) Low ion sodium (Na) Low sodium (Na) Hyponatremia Increase LDL/HDL Blood glucose levels may increase (hyperglycemia) Potassium-sparing diuretics Amiloride potassium retention. Hyperkalemia Low sodium (Na) Hyponatremia

β- blockers Indications: Reduction in heart rate and decreases cardiac output. Cardiac contractility is decreased (ventricles contraction. Precautions( adverse effect ): I. Diabetes: β-Blockers can mask hypoglycemic symptoms, such as tachycardia. II. Asthma and chronic obstructive pulmonary disease (COPD)

β-Adrenergic blockers( examples ) β 1 – receptor blocker β 1 - and β 2 blocker (non-selective β blocker) α 1 -β blocker β-blockers have a greater tendency to occupy the β 1 - receptor in the heart β 1 receptor– in the heart β 2 receptor - in the lungs α 1 receptor - in blood vessel Metoprolol Propranolol Labetalol Atenolol Nadolol Carvedilol Bisoprolol Timolol

α 1 -adrenergic blockers Prazosin. Terazosin. Doxazosin. The α 1 -blockers ( indirect Vasodilators) causing vasodilation of both arteries and veins. Precautions and monitoring effects: 1 - First -dose phenomenon: occur within 30 -90 min of the first dose; cause hypotension, nausea, dizziness, headache, palpitations, and sweating. To minimize these effects, the first dose should be limited to a small dose and administered just before bedtime.

Centrally active α-agonists They act primarily within the CNS on α 2 - receptors to decrease sympathetic out f low to the cardiovascular system. Methyldopa is drug of choice for treatment of hypertension, Sedation, decreased mental activity, sleep disturbances, and depression.

ACE inhibitors (ACE I) Captopril. Actions: These agents inhibit the conversion of angiotensin I ( weak vasoconstrictor ) to angiotensin II (a strong vasoconstrictor ) inhibit fluid volume increases (sodium and water retention). Final result: decrease in fluid volume, along with peripheral vasodilation. Precautions: Hyperkalemia. The mechanism of act ion tends to increase potassium levels. dry cough.

Angiotensin receptor antagonists(ARA) Candesarn. Telmisartan. Valsartan. Blocking the binding of angiotensin II to the angiotensin II receptors. these agents decrease the vasoconstrictor effects of angiotensin II Precautions: Similar to ACE inhibitors, increases in serum potassium levels can occur. Dose not cause cough.

Calcium-channel blockers Diltiazem Verapamil Actions: Calcium-channel blockers inhibit the influx of calcium through slow channels in vascular smooth muscle and cause relaxation. Significant interactions. With Β blockers, when used with calcium channel blockers, may have an additive effect on inducing HF and bradycardia.

Direct Vasodilators. Directly relaxes arterioles decreasing peripheral resistance. for managing hypertensive crisis Hydralazine: Reflex tachycardia is common and should be considered before initiating therapy. Minoxidil : can cause excessive hair growth) is a common side effect, particularly if the drug is continued for > 4 weeks. Nitroprusside : toxicity can occurs with high doses

Hypertensive Emergencies A hypertensive emergency is a severe elevation of blood pressure(> 200 mm Hg systolic or > 140 mm Hg diastolic) Rapid-Acting Parenteral (IV Rout administer ) Antihypertensive Agents for Hypertensive Crisis (Nitroprusside) as IV infusion. (Hydralazine) as IV/IM