rationale for pharmacologic treatment of hypertension

8/3/2019 Rationale for Pharmacologic Treatment of Hypertension

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Rationale for Pharmacologic Treatment of Hypertension

Patients withprimary hypertensionare generally treated with drugs that 1) reduce blood volume (which

reduces central venous pressure and cardiac output), 2) reduce systemic vascular resistance, or 3) reduce

cardiac output by depressing heart rate and stroke volume. Patients withsecondary hypertensionare best

treated by controlling or removing the underlying disease or pathology, although they may still requireantihypertensive drugs.

Rationale for Reducing

Arterial Pressure

Reduce Cardiac Output

Reduce blood volume

Reduce heart rate

Reduce stroke volume

Reduce Systemic Vascular Resistance

Dilate systemic vasculature

Arterial pressure can be reduced by decreasingcardiac output,systemic vascular resistance, orcentral

venous pressure. An effective and inexpensive way of reducing venous pressure and cardiac output is by

using drugs that reduceblood volume. These drugs (diuretics) act on the kidney to enhance sodium and

water excretion. Reducing blood volume not only reduces central venous pressure, but even more

importantly, reduces cardiac output by theFrank-Starling mechanismdue to the reduction inventricular

preload. An added benefit of these drugs is that they reduce systemic vascular resistance with long-term

use.

Many antihypertensive drugs have their primary action on systemic vascular resistance. Some of these

drugs produce vasodilation by interfering with sympathetic adrenergic vascular tone (sympatholytics) or

by blocking the formation of angiotensin II or its vascular receptors. Other drugs are direct arterial dilators,

and some are mixed arterial and venous dilators. Although less commonly used because of a high

incidence of side effects, there are drugs that act on regions in the brain that control sympathetic autonomic

outflow. By reducing sympathetic efferent activity, centrally acting drugs decrease arterial pressure by

decreasing systemic vascular resistance and cardiac output.

Some antihypertensive drugs, most notably beta-blockers, depress heart rate and contractility (this

decreases stroke volume) by blocking the influence of sympathetic nerves on the heart. Calcium-channel

blockers, especially those that are more cardioselective, also reduce cardiac output by decreasing heart rate

and contractility. Some calcium-channel blockers (most notably the dihydropyridines) are more selective

for the systemic vasculature and therefore reduce systemic vascular resistance.

Drugs Used to Treat Hypertension

Classes of drugs used in the treatment of hypertension are listed below. Clicking on the drug class will

link you to the page describing the pharmacology of that drug class.

Diuretics

- thiazide diuretics- loop diuretics
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- potassium-sparing diuretics

Vasodilators

- alpha-adrenoceptor antagonists (alpha-blockers)

- angiotensin converting enzyme inhibitors (ACE inhibitors)- angiotensin receptor blockers (ARBs)

- calcium-channel blockers

- direct acting arterial dilators

- ganglionic blockers

- nitrodilators

- potassium-channel openers

- renin inhibitors

Cardioinhibitory drugs

- beta-blockers- calcium-channel blockers

Centrally acting sympatholytics
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Anti-hypertensive (Other Agents)

Aliskiren (Tekturna) bosentan (tracleer )

clonidine (Catapres ) epoprostenol (Flolan )fenoldopam (Corlopam ) hydralazine (Apresoline )

methyldopa (Aldomet ) minoxidil (Loniten )

nitroprusside (Nipride ) phentolamine (regitine )

treprostinil (Remodulin )

Aliskiren (Tekturna)Drug Category: Renin Inhibitor. Indication: Treatment of hypertension, alone or incombination with other antihypertensive agents.

Dosing (Adults):Hypertension: Initial: 150 mg once daily; may increase to 300 mg once daily(maximum: 300 mg/day). Note: Prior to initiation, correct hypovolemia and/orclosely monitor volume status in patients on concurrent diuretics during treatmentinitiation.

Renal dosing:Mild-to-moderate impairment [GFR >30 mL/minute and/or Scr


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Clonidine hydrochloride acts relatively rapidly. The patient's blood pressuredeclines within 30 to 60 minutes after an oral dose, the maximum decreaseoccurring within 2 to 4 hours. Renal blood flow and glomerular filtration rate remainessentially unchanged. Normal postural reflexes are intact; therefore, orthostaticsymptoms are mild and infrequent.

Acute studies with clonidine hydrochloride in humans have demonstrated amoderate reduction (15% to 20%) of cardiac output in the supine position with nochange in the peripheral resistance: at a 45 tilt there is a smaller reduction incardiac output and a decrease of peripheral resistance. During long-term therapy,cardiac output tends to return to control values, while peripheral resistance remainsdecreased. Slowing of the pulse rate has been observed in most patients givenclonidine, but the drug does not alter normal hemodynamic response to exercise.

Tolerance to the antihypertensive effect may develop in some patients,necessitating a re-evaluation of therapy.Other studies in patients have provided evidence of a reduction in plasma reninactivity and in the excretion of aldosterone and catecholamines. The exactrelationship of these pharmacologic actions to the antihypertensive effect ofclonidine has not been fully elucidated.

Clonidine acutely stimulates growth hormone release in both children and adults,but does not produce a chronic elevation of growth hormone with long-term use.

PharmacokineticsThe plasma level of clonidine peaks in approximately 3 to 5 hours and the plasma

half-life ranges from 12 to 16 hours. The half-life increases up to 41 hours inpatients with severe impairment of renal function. Following oral administrationabout 4060% of the absorbed dose is recovered in the urine as unchanged drug in24 hours. About 50% of the absorbed dose is metabolized in the liver.

INDICATIONS AND USAGEClonidine hydrochloride is indicated in the treatment of hypertension. Clonidinehydrochloride may be employed alone or concomitantly with other antihypertensiveagents.

DOSAGE AND ADMINISTRATION

TABLETS:--------------------------------Adults: The dose of clonidine hydrochloride must be adjusted according to thepatient's individual blood pressure response. The following is a general guide to itsadministration.

Initial Dose0.1 mg tablet twice daily (morning and bedtime). Elderly patients may benefit from alower initial dose.

Maintenance Dose

Further increments of 0.1 mg per day may be made at weekly intervals if necessaryuntil the desired response is achieved. Taking the larger portion of the oral daily


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dose at bedtime may minimize transient adjustment effects of dry mouth anddrowsiness. The therapeutic doses most commonly employed have ranged from0.2 mg to 0.6 mg per day given in divided doses. Studies have indicated that 2.4mg is the maximum effective daily dose, but doses as high as this have rarely beenemployed.

Other:Hypertensive urgency: Initial 0.1-0.2 mg x 1, then 0.1 mg q1h prn, to a maximumtotal dose of 0.6 mg

HOW SUPPLIED (TABLETS)0.1 mg, 0.2 mg, 0.3 mg

TRANSDERMAL PATCH:---------------------------------Apply Clonidine Transdermal Systems once every 7 days to a hairless area ofintact skin on the upper outer arm or chest. Each new application of ClonidineTransdermal System should be on a different skin site from the previous location. Ifthe system loosens during 7-day wearing, the adhesive cover should be applieddirectly over the system to ensure good adhesion. There have been rare reports ofthe need for patch changes prior to 7 days to maintain blood pressure control.

To initiate therapy, Clonidine Transdermal System dosage should be titratedaccording to individual therapeutic requirements, starting with ClonidineTransdermal System 0.1 mg. If after one or two weeks the desired reduction in

blood pressure is not achieved, increase the dosage by adding another ClonidineTransdermal System 0.1 mg or changing to a larger system. An increase in dosageabove two Clonidine Transdermal System 0.3 mg is usually not associated withadditional efficacy.

When substituting Clonidine Transdermal System for oral clonidine or for otherantihypertensive drugs, physicians should be aware that the antihypertensive effectof Clonidine Transdermal System may not commence until 2-3 days after initialapplication. Therefore, gradual reduction of prior drug dosage is advised. Some orall previous antihypertensive treatment may have to be continued, particularly inpatients with more severe forms of hypertension.

Renal Impairment: Dosage must be adjusted according to the degree ofimpairment, and patients should be carefully monitored. Since only a minimalamount of clonidine is removed during routine hemodialysis, there is no need togive supplemental clonidine following dialysis.

HOW SUPPLIEDClonidine Transdermal Systems 0.1 mg, Clonidine Transdermal Systems 0.2 mg,and Clonidine Transdermal Systems 0.3 mg are supplied as 4 pouched systemsand 4 adhesive covers per carton.

Renal Impairment


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Dosage must be adjusted according to the degree of impairment, and patientsshould be carefully monitored. Since only a minimal amount of clonidine is removedduring routine hemodialysis, there is no need to give supplemental clonidinefollowing dialysis.

epoprostenol (Flolan )Epoprostenol (PGI2, prostacyclin): a naturally occurring prostaglandin with potentvasodilatory activity and inhibitory activity of platelet aggregation. Indication: long-term intravenous treatment of primary pulmonary hypertension and pulmonaryhypertension associated with the scleroderma spectrum of disease in NYHA ClassIII and Class IV patients who do not respond adequately to conventional therapy.

Dosage - Adult (usual) Pulmonary hypertension: initial, 2 ng/kg/min IV, titrateupward in increments of 2 ng/kg/min every 15 min or longer until dose-limitingpharmacological effects are elicited or until tolerance develops.Administration: reconstitute only with supplied diluent; do not give with otherparenteral medications. Infuse continuous chronic infusion via a central venouscatheter with an ambulatory infusion pump - may be administered peripherally untilcentral catheter established. Avoid abrupt withdrawal. Anticipate need for periodicdose adjustments.

fenoldopam (Corlopam )Mechanism of ActionFenoldopam is a rapid-acting vasodilator. It is an agonist for D1-like dopaminereceptors and binds with moderate affinity to 2-adrenoceptors. It has nosignificant affinity for D2-like receptors, 1 and adrenoceptors, 5HT1 and 5HT2

receptors, or muscarinic receptors. Fenoldopam is a racemic mixture with the R-isomer responsible for the biological activity. The R-isomer has approximately 250-fold higher affinity for D1-like receptors than does the S-isomer. In non-clinicalstudies, fenoldopam had no agonist effect on presynaptic D2-like dopaminereceptors, or - or -adrenoceptors, nor did it affect angiotensin-convertingenzyme activity. Fenoldopam may increase norepinephrine plasma concentration.

In animals, fenoldopam has vasodilating effects in coronary, renal, mesenteric andperipheral arteries. All vascular beds, however, do not respond uniformly tofenoldopam. Vasodilating effects have been demonstrated in renal efferent andafferent arterioles

INDICATIONS AND USAGEAdult Patients: Fenoldopam is indicated for the in-hospital, short-term (up to 48hours) management of severe hypertension when rapid, but quickly reversible,emergency reduction of blood pressure is clinically indicated, including malignanthypertension with deteriorating end-organ function. Transition to oral therapy withanother agent can begin at any time after blood pressure is stable duringfenoldopam infusion.

Pediatric Patients: Fenoldopam is indicated for the in-hospital, short-term (up to 4hours) reduction in blood pressure (See Package insert for CLINICAL

PHARMACOLOGY/Pediatric Patients).
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Dosage (adult): Hypertension: initial 0.03-0.1 mcg/kg/min IV; increase every 15 minby 0.05-0.1 mcg/kg/min based on response. Maximum: 1.6 mcg/kg/min. In clinicaltrials, doses from 0.01-1.6 g/kg/min have been studied. Most of the effect of agiven infusion rate is attained in 15 minutes. A bolus dose should not be used.Hypotension and rapid decreases of blood pressure should be avoided. The initial

dose should be titrated upward or downward, no more frequently than every 15minutes (and less frequently as goal pressure is approached) to achieve thedesired therapeutic effect. The recommended increments for titration are 0.05-0.1g/kg/min.

[Supplied: 10 mg/ml solution]

hydralazine (Apresoline )Overview: Although the precise mechanism of action of hydralazine is not fullyunderstood, the major effects are on the cardiovascular system. Hydralazineapparently lowers blood pressure by exerting a peripheral vasodilating effectthrough a direct relaxation of vascular smooth muscle. Hydralazine, by alteringcellular calcium metabolism, interferes with the calcium movements within thevascular smooth muscle that are responsible for initiating or maintaining thecontractile state.

The peripheral vasodilating effect of hydralazine results in decreased arterial bloodpressure (diastolic more than systolic); decreased peripheral vascular resistance;and an increased heart rate, stroke volume, and cardiac output. The preferentialdilatation of arterioles, as compared to veins, minimizes postural hypotension andpromotes the increase in cardiac output. Hydralazine usually increases renin

activity in plasma, presumably as a result of increased secretion of renin by therenal juxtaglomerular cells in response to reflex sympathetic discharge. Thisincrease in renin activity leads to the production of angiotensin II, which thencauses stimulation of aldosterone and consequent sodium reabsorption.Hydralazine also maintains or increases renal and cerebral blood flow.

Hydralazine is rapidly absorbed after oral administration, and peak plasma levelsare reached at 1-2 hours. Plasma levels of apparent hydralazine decline with a half-life of 3-7 hours. Binding to human plasma protein is 87% Plasma levels ofhydralazine vary widely among individuals. Hydralazine is subject to polymorphicacetylation; slow acetylators generally have higher plasma levels of hydralazine

and require lower doses to maintain control of blood pressure. Hydralazineundergoes extensive hepatic metabolism; it is excreted mainly in the form ofmetabolites in the urine.

Dosing (Adult): Initial (Acute hypertension): 10 mg slow IV bolus ( maximum dosebeing 20 mg) every 4 to 6 hours as needed. May increase to 40 mg/dose. Changeto oral therapy as soon as possible. The fall in blood pressure begins within 10 to30 minutes and lasts 2 to 4 hours. May also be given IM.

Hypertension (Oral): Initial: 10 mg 4 times/day. Increase by 10-25 mg/dose every

2-5 days (maximum: 300 mg/day). Usual dose range (JNC 7): 25-100 mg/day in 2divided doses.
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Pre-eclampsia/eclampsia: 5 mg/dose (IM, IV) then 5-10 mg every 20-30 minutesas needed.

CHF: Initial dose: 10-25 mg orally 3-4 times/day. Dosage must be adjusted based

on individual response. Target dose: 75 mg 4 times daily in combination withisosorbide dinitrate (40 mg 4 times daily). Range: Typically 200-600 mg daily in 2-4divided doses. Dosages as high as 3 grams per day have been used in somepatients for symptomatic and hemodynamic improvement.

Renal dosing: crcl 10-50 ml/min: Administer every 8 hours. crcl


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with a thiazide or if effective control of blood pressure cannot be maintained on 2 gof methyldopa daily.

Methyldopa is largely excreted by the kidney and patients with impaired renalfunction may respond to smaller doses. Syncope in older patients may be related to

an increased sensitivity and advanced arteriosclerotic vascular disease. This maybe avoided by lower doses.

====================================

I.V.: 250-1000 mg every 6-8 hours; maximum: 1 g every 6 hours

====================================

CLINICAL PHARMACOLOGYMethyldopa is an aromatic-aminoacid decarboxylase inhibitor in animals and inman. Although the mechanism of action has yet to be conclusively demonstrated,the antihypertensive effect of methyldopa probably is due to its metabolism toalpha-methylnorepinephrine, which then lowers arterial pressure by stimulation ofcentral inhibitory alpha-adrenergic receptors, false neurotransmission, and/orreduction of plasma renin activity. Methyldopa has been shown to cause a netreduction in the tissue concentration of serotonin, dopamine, norepinephrine, andepinephrine.

Only methyldopa, the L-isomer of alpha-methyldopa, has the ability to inhibit dopadecarboxylase and to deplete animal tissues of norepinephrine. In man, the

antihypertensive activity appears to be due solely to the L-isomer. About twice thedose of the racemate (DL-alpha-methyldopa) is required for equal antihypertensiveeffect.

Methyldopa has no direct effect on cardiac function and usually does not reduceglomerular filtration rate, renal blood flow, or filtration fraction. Cardiac outputusually is maintained without cardiac acceleration. In some patients the heart rateis slowed.

Normal or elevated plasma renin activity may decrease in the course of methyldopatherapy.

Methyldopa reduces both supine and standing blood pressure. It usually produceshighly effective lowering of the supine pressure with infrequent symptomaticpostural hypotension. Exercise hypotension and diurnal blood pressure variationsrarely occur.

INDICATIONS AND USAGEHypertension.

CONTRAINDICATIONS

Methyldopa is contraindicated in patients: with active hepatic disease, such as acute hepatitis and active cirrhosis.


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with liver disorders previously associated with methyldopa therapy (see packageinsert for WARNINGS). with hypersensitivity to any component of this product. on therapy with monoamine oxidase (MAO) inhibitors.

WARNINGSIt is important to recognize that a positive Coombs test, hemolytic anemia, and liverdisorders may occur with methyldopa therapy.The rare occurrences of hemolyticanemia or liver disorders could lead to potentially fatal complications unlessproperly recognized and managed. Read this section carefully to understand thesereactions.

HOW SUPPLIEDTABLETS: 250 mg and 500 mgI.V.: Methyldopate HCl Injection, USP 250 mg/5 mL (50 mg/mL).

minoxidil (Loniten )Severe Hypertension: initial, 5 mg/day orally as single dose or 2 divided doses.Maintenance (HTN): 10-40 mg/day orally daily in 1-2 divided doses (Maximum: 100mg/day) . Acts directly on vascular smooth muscle with selective vasodilatation ofthe arteriolar resistance vessels and little or no effects on venous capacitancevessels and does not effect the functioning of the carotid or aortic baroreceptors.

[Supplied: 2.5, 5, 10mg tablet]

nitroprusside (Nipride )

Arteriolar and venous dilator. Considered to be the most effective parenteral drugfor most hypertensive emergencies (except myocardial ischemia or renalimpairment). It dilates both arteries and veins, and it reduces afterload and preload.Onset: within seconds. Duration: 2-3 minutes. Constant monitoring of the bloodpressure is required.Alternatives to nitroprusside include intravenous labetalol, nicardipine, andfenoldopam. Hypotension is uncommon with these drugs and cyanide toxicity is notan issue.

Dosing (Adults): Initial: 0.3-0.5 mcg/kg/minute. Increase in increments of 0.5mcg/kg/minute -- titrating to the desired hemodynamic effect or the appearance of

headache or nausea. Usual dose: 3 mcg/kg/minute (rarely need >4 mcg/kg/minute).Maximum: 10 mcg/kg/minute.

When treatment is prolonged (>24 to 48 hours) or when renal insufficiency ispresent, the risk of cyanide and thiocyanate toxicity is increased. Doses > 2mcg/kg/min exceed the capacity of the body to detoxify cyanide. Maximum doses of10 mcg/kg/min should never be given for more than 10 minutes. An infusion ofsodium thiosulfate can be used in affected patients to provide a sulfur donor todetoxify cyanide into thiocyanate.

Supplied: Injection (Soln): 25 mg/ml - 2 ml (vial).

phentolamine (regitine )
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CLINICAL PHARMACOLOGYPhentolamine mesylate produces an alpha-adrenergic block of relatively shortduration. It also has direct, but less marked, positive inotropic and chronotropiceffects on cardiac muscle and vasodilator effects on vascular smooth muscle.

Phentolamine has a half-life in the blood of 19 minutes following intravenousadministration. Approximately 13% of a single intravenous dose appears in theurine as unchanged drug.

INDICATIONS AND USAGEPhentolamine Mesylate for Injection is indicated for the prevention or control ofhypertensive episodes that may occur in a patient with pheochromocytoma as aresult of stress or manipulation during preoperative preparation and surgicalexcision.

Phentolamine Mesylate for Injection is indicated for the prevention or treatment ofdermal necrosis and sloughing following intravenous administration orextravasation of norepinephrine.

Phentolamine Mesylate for Injection is also indicated for the diagnosis ofpheochromocytoma by the phentolamine blocking test.

CONTRAINDICATIONSMyocardial infarction, history of myocardial infarction, coronary insufficiency,

angina, or other evidence suggestive of coronary artery disease; hypersensitivity tophentolamine or related compounds.

WARNINGSMyocardial infarction, cerebrovascular spasm, and cerebrovascular occlusion havebeen reported to occur following the administration of phentolamine, usually inassociation with marked hypotensive episodes.

For screening tests in patients with hypertension, the generally available urinaryassay of catecholamines or other biochemical assays have largely replaced the

phentolamine and other pharmacological tests for reasons of accuracy and safety.None of the chemical or pharmacological tests is infallible in the diagnosis ofpheochromocytoma. The phentolamine blocking test is not the procedure of choiceand should be reserved for cases in which additional confirmatory evidence isnecessary and the relative risks involved in conducting the test have beenconsidered.

Dosing:Extravasation - norepinephrine: 5-10 mg in 10 mL saline SC infiltrated within 12hours into area of extravasation.Hypertensive crisis: 5-20 mg IV.

Pheochromocytoma (diagnosis): 5 mg IV or IM.Tissue necrosis prevention: 10 milligrams may be added to each liter of solution


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containing norepinephrine to prevent dermal necrosis and sloughing associatedwith intravenous administration of norepinephrine.

treprostinil (Remodulin )Mechanism Of Action

The major pharmacologic actions of treprostinil are direct vasodilation of pulmonaryand systemic arterial vascular beds, and inhibition of platelet aggregation

Indications: Pulmonary arterial hypertension (PAH) in patients with NYHA Class II-IV symptoms.Dosage: Pulmonary arterial hypertension: initial, 1.25 ng/kg/min continuous SCinfusion; decrease to 0.625 ng/kg/min if initial dose cannot be tolerated. Pulmonaryarterial hypertension: adjustments, increase dose in increments of no more than1.25 ng/kg/min per week for the first 4 weeks and then no more than 2.5 ng/kg/minper week for remaining duration.Administration: administer by continuous subcutaneous infusion to diminishsymptoms associated with exercise. avoid abrupt cessation of infusion. Chronicdosage adjustments should establish a dose at which PAH symptoms areimproved, while minimizing side effects. Minimal experience with doses greaterthan 40 ng/kg/min.

[Supplied (20 ml vials) 1, 2.5 , 5, and 10 mg/ml solution]

DisclaimerListed dosages are for - Adult patients ONLY. PLEASE READ

THEDISCLAIMERCAREFULLY BEFORE ACCESSING OR USING THIS SITE.BY ACCESSING OR USING THIS SITE, YOU AGREE TO BE BOUND BY THE

TERMS AND CONDITIONS SET FORTH IN THE DISCLAIMER. GlobalRPH doesnot directly or indirectly practice medicine or provide medical services and thereforeassumes no liability whatsoever of any kind for the information and data accessed

through the Service or for any diagnosis or treatment made in reliance thereon.

David F. McAuley, Pharm.D., R.Ph. GlobalRPh Inc.

Anti-Hypertensive Drugs are medicines that are used to help lower blood pressure or reduce hypertension.

High Blood Pressure and HypertensionAnti-Hypertensive Drugs are used to help control blood pressure in people whose blood pressure is too high.Some people have blood pressure that stays high all the time. This condition is known as hypertension. Beingaware of high blood pressure and doing something to control it are very. Untreated, high blood pressure can leadto diseases of the heart, arteries, kidney damage, or stroke.

For high blood pressure treatment, the type of hypertension needs to be known. In most cases the common

cause of high blood pressure is Essential or Primary Hypertension, which means that the high blood pressure isnot caused by some other medical condition. Such high pressure problems can be controlled by anti
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hypertension medication and changes in diet, doing regular exercise, and controlling weight. Controlling primaryhypertension is a life long treatment.

The other type of hypertension is secondary hypertension. This is caused due to medical problems like kidneydisease, narrowing of certain arteries, or adrenal glands tumors. Correcting these problems often cures theproblem of high blood pressure, and no further treatment is needed.

How Does Hypertension Medication Works?Hypertension medication works in the following ways:

o They reduce blood volume. This in turn reduces central venous pressure and cardiac output).

o They reduce systemic vascular resistance.

o They reduce cardiac output by depressing heart rate and stroke volume.

Drugs Used to Treat Hypertension/High Blood PressureMany different types of drugs are used, alone or in combination with other drugs, to treat hypertension/high bloodpressure. The major categories are:

o Angiotensin-converting Enzyme (ACE) Inhibitors: They work by preventing a chemical in the blood, angiotensin I,

from being converted into a substance that increases water and salt retention in the body. They make blood

vessels relax, which further reduces blood pressure.

o Angiotensin II Receptor Antagonists: They act at a later step in the same process that ACE inhibitors affect. Like

ACE inhibitors, they lower blood pressure by relaxing blood vessels.

o

Beta blockers: Beta blockers affect the body's response to certain nerve impulses. This, in turn, decreases theforce and rate of the heart's contractions, which lowers blood pressure.

o Blood Vessel Dilators (Vasodilators): These drugs lower blood pressure by relaxing muscles in the blood vessel

walls.

o Calcium Channel Blockers: They slow the movement of calcium into the cells of blood vessels. This relaxes the

blood vessels and lowers blood pressure.

o Diuretics: They control blood pressure by eliminating excess salt and water from the body.

o Nerve Blockers: They control nerve impulses along certain nerve pathways. This allows blood vessels to relax

and lowers blood pressure.

Popular Hypertension Drugs

o Propranolol (Inderal)

o Atenolol (Tenormin)

o Pindolol (Visken)

o Losartan (Cozaar)


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o Candesartan (Atacand)

o lirbesartan (Avapro)

o Telmisartan (Micardis)

o Valsartan (Diovan)

o Eprosartan (Teveten) etc.

Antihypertensive drugs

Antihypertensive drugs are used to treat high blood pressure, a condition also known as hypertension.

What are the types of antihypertensive drugs?

How are antihypertensive drugs used?

What are the side effects of antihypertensive drugs?

Jupiter

High blood pressure (see Hypertension) requires treatment mainly because it increases the risk of both coronaryartery disease andstroke. Antihypertensive drugs are most often used when changes in your lifestyle, such asimproving your diet, doing more exercise, and giving up smoking, fail to produce an adequate fall in bloodpressure over a short period of time. Antihypertensives are also used to treat hypertension in pregnancy (seePre-eclampsia and eclampsia).

Common drugs

ACE inhibitor drugs: Alpha-blocker drugs: Doxazosin, Prazosin, Terazosin

Angiotensin II blocker

drugs:

Beta-blocker drugs:

Calcium channel blocker

drugs:

Centrally acting drugs: Methyldopa, Moxonidine

Diuretic drugs: Other antihypertensive drugs: Diazoxide, Hydralazine,

Minoxidil, Nitroprusside

What are the types of antihypertensive drugs?
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There are many different types of antihypertensive drugs. The types that are most commonly used arebeta-blocker drugs,ACE inhibitor drugs,angiotensin II blocker drugs,calcium channel blocker drugs,anddiuretic drugs. Less commonly, alpha-blocker drugs, centrally acting drugs, and other drugs, includingdiazoxide, hydralazine, and minoxidil, are used. Most types of antihypertensive drug reduce high blood pressureby increasing the diameter of the blood vessels (a process known as vasodilation) or by reducing the force withwhich the heart pumps the blood. ACE inhibitors, alpha-blockers, angiotensin II blockers, calcium channelblockers, and centrally acting drugs act in a variety of ways to cause vasodilation. Beta-blockers lower blood

pressure by reducing the force with which the heart pumps. This effect is achieved by blocking the action ofsubstances produced naturally by the body that increase heart rate and blood pressure. Diuretics cause thekidneys to excrete more water and salts than usual, which reduces the volume of blood that is present in thecirculation and thereby lowers blood pressure.

How are antihypertensive drugs used?

Antihypertensives are normally taken orally over long periods of time and often for life. However, in some cases itis possible to reduce the dose gradually and eventually stop the drugs if blood pressure returns to normalfollowing long-term changes in weight or lifestyle. The choice of drug depends on several factors, including ageand other medical conditions that might be present. Certain drugs are especially likely to cause side effects inelderly people. If you have mild or moderate hypertension, you will usually be prescribed a single drug, such as adiuretic or a beta-blocker. These drugs are not suitable for everyone. For example, they may make the controlofdiabetes mellitusmore difficult. An ACE inhibitor or a calcium channel blocker may be used instead. If yourblood pressure is not controlled adequately by a single drug, you may be given a combination of two or three

other types of antihypertensive drugs in order to reduce blood pressure to a safe level. You may be given alpha-blockers or centrally acting drugs if other drugs or combinations of drugs have not reduced your blood pressuresufficiently or if other antihypertensives are unsuitable. Unless you have severe hypertension, your doctor willusually start you on a low dose of a drug. The dose is then gradually increased until your blood pressure isnormal or until you experience side effects. Your blood pressure will be monitored frequently until it is stable at asafe level.

What are the side effects of antihypertensive drugs?

All antihypertensive drugs, in particular ACE inhibitors and alpha-blockers, can cause a sudden drop in bloodpressure (see Hypotension) when you first take them. This drop in blood pressure can cause light-headedness.The drugs may also cause drowsiness. If you experience these side effects, your doctor may reduce the dose ormay give you a different drug. You should not stop taking an antihypertensive without first consulting your doctor.Other side effects are associated with specific types of antihypertensive drugs. Several types of these drugs,especially beta-blockers and some diuretics, may cause erectile dysfunction; ACE inhibitors sometimes cause a

dry cough and calcium channel blockers may cause swollen ankles, flushing, and headaches. Long-term use ofdiuretics may increase the risk of gout. Minoxidil may result in excessive hairand hydralazine may causepalpitations.

Warning

Do not suddenly stop taking an antihypertensive drug without first consulting your doctor. Abrupt withdrawal ofthe drug could cause a rapid increase in blood pressure.

BMA Complete Family Health GuideCopyright 2005 Dorling Kindersley

Posted 30.06.2010
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rationale for pharmacologic treatment of hypertension

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