Antihypertensive Agents Copyright 2002 1998 Elsevier Science USA

Hypertension High blood pressure • Normal: Systolic < 130 mm Hg Diastolic < 85

Classification of Blood Pressure Category Systemic BP (mm Hg) Diastolic BP (mm Hg) Normal

Classification of Blood Pressure Primary Hypertension • Specific cause unknown • 90% of the

Blood Pressure = CO x SVR • CO = Cardiac output • SVR =

Instructors may want to insert EIC Image #69: Blood Pressure: Normal Regulation Copyright ©

Antihypertensive Agents • Medications used to treat hypertension Copyright © 2002, 1998, Elsevier Science

Antihypertensive Agents: Categories • Adrenergic agents • Angiotensin-converting enzyme inhibitors • Angiotensin II receptor

Antihypertensive Agents: Categories • Adrenergic Agents – Alpha 1 blockers – Beta blockers (cardioselective

Antihypertensive Agents: Mechanism of Action Adrenergic Agents Alpha 1 Blockers (peripherally acting) • •

Antihypertensive Agents: Adrenergic Agents Alpha 1 Blockers • doxazosin (Cardura) • prazosin (Minipress) •

Antihypertensive Agents: Mechanism of Action Adrenergic Agents Central-Acting Adrenergics • Stimulate alpha 2 -adrenergic

Antihypertensive Agents: Adrenergic Agents Central-Acting Adrenergics • clonidine (Catapres) • methyldopa (Aldomet) (drug of

Antihypertensive Agents: Mechanism of Action Adrenergic Agents Adrenergic Neuronal Blockers (peripherally acting) • Inhibit

Antihypertensive Agents: Adrenergic Agents Adrenergic Neuronal Blockers (peripherally acting) • reserpine • guanadrel (Hylorel)

Antihypertensive Agents: Adrenergic Agents Therapeutic Uses • Alpha 1 blockers (peripherally acting) – Treatment

Antihypertensive Agents: Adrenergic Agents Therapeutic Uses • Central-Acting Adrenergics – Treatment of hypertension, either

Antihypertensive Agents: Adrenergic Agents Therapeutic Uses • Adrenergic neuronal blockers (peripherally acting) – Treatment

Antihypertensive Agents: Adrenergic Agents Side Effects Most common: sedation dry mouth drowsiness constipation Other:

Antihypertensive Agents: Categories Angiotensin-Converting Enzyme Inhibitors (ACE Inhibitors) • Large group of safe and

Antihypertensive Agents: Mechanism of Action ACE Inhibitors RAAS: Renin Angiotensin-Aldosterone System • When the

Antihypertensive Agents: Mechanism of Action ACE Inhibitors • Aldosterone stimulates water and sodium resorption.

Antihypertensive Agents: Mechanism of Action ACE Inhibitors • ACE Inhibitors block the angiotensin-converting enzyme,

Antihypertensive Agents ACE Inhibitors • captopril (Capoten) • Short half-life, must be dosed more

Antihypertensive Agents: Therapeutic Uses ACE Inhibitors • Hypertension • CHF (either alone or in

Antihypertensive Agents: Side Effects ACE Inhibitors • Fatigue Dizziness • Headache Mood changes •

Antihypertensive Agents: Categories Angiotensin II Receptor Blockers (A II Blockers or ARBs) • Newer

Antihypertensive Agents: Mechanism of Action Angiotensin II Receptor Blockers • Allow angiotensin I to

Antihypertensive Agents: Angiotensin II Receptor Blockers • losartan (Cozaar) • eposartan (Teveten) • valsartan

Antihypertensive Agents: Therapeutic Uses Angiotensin II Receptor Blockers • Hypertension • Adjunctive agents for

Antihypertensive Agents: Side Effects Angiotensin II Receptor Blockers • Upper respiratory infections • Headache

Antihypertensive Agents: Categories Calcium Channel Blockers • Benzothiazepines • Dihydropyridines • Phenylalkylamines Copyright ©

Antihypertensive Agents: Mechanism of Action Calcium Channel Blockers • Cause smooth muscle relaxation by

Antihypertensive Agents Calcium Channel Blockers • Benzothiazepines: – diltiazem (Cardizem, Dilacor) • Phenylalkamines: –

Antihypertensive Agents: Therapeutic Uses Calcium Channel Blockers • Angina • Hypertension • Dysrhythmias •

Antihypertensive Agents: Side Effects Calcium Channel Blockers • Cardiovascular – hypotension, palpitations, tachycardia •

Antihypertensive Agents: Diuretics • Decrease the plasma and extracellular fluid volumes • Results: decreased

Antihypertensive Agents: Mechanism of Action Vasodilators • Directly relaxes arteriolar smooth muscle • Result:

Antihypertensive Agents Vasodilators • diazoxide (Hyperstat) • hydralazine HCl (Apresoline) • minoxidil (Loniten, Rogaine)

Antihypertensive Agents: Therapeutic Uses Vasodilators • Treatment of hypertension • May be used in

Antihypertensive Agents: Side Effects Vasodilators • Hydralazine: – dizziness, headache, anxiety, tachycardia, nausea and

Antihypertensive Agents: Nursing Implications • Before beginning therapy, obtain a thorough health history and

Antihypertensive Agents: Nursing Implications • Educate patients about the importance of not missing a

Antihypertensive Agents: Nursing Implications • Instruct patients that these drugs should not be stopped

Antihypertensive Agents: Nursing Implications • Remind patients that medications is only part of therapy.

Antihypertensive Agents: Nursing Implications • Instruct patients to change positions slowly to avoid syncope

Antihypertensive Agents: Nursing Implications • Men taking these agents may not be aware that

Antihypertensive Agents: Nursing Implications • Hot tubs, showers, or baths; hot weather; prolonged sitting

Antihypertensive Agents: Nursing Implications • Monitor for side/adverse effects (dizziness, orthostatic hypotension, fatigue) and

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Classification of Blood Pressure Category Systemic BP (mm Hg) Diastolic BP (mm Hg) Normal <130 <85 High normal 130 -139 Hypertension 140 -159 100 -109 110 -119 85 -89 90 -99 Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Stage 1 Stage 2 160 -169 Stage 3 180 -209 Stage 4 210 120

Classification of Blood Pressure Primary Hypertension • Specific cause unknown • 90% of the cases • Also known as essential or idiopathic hypertension Secondary Hypertension • Cause is known (such as eclampsia of pregnancy, renal artery disease, pheochromocytoma) • 10% of the cases Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Categories • Adrenergic agents • Angiotensin-converting enzyme inhibitors • Angiotensin II receptor blockers • Calcium channel blockers • Diuretics • Vasodilators Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Categories • Adrenergic Agents – Alpha 1 blockers – Beta blockers (cardioselective and nonselective) – Centrally acting alpha blockers – Combined alpha-beta blockers – Peripheral-acting adrenergic agents Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Mechanism of Action Adrenergic Agents Alpha 1 Blockers (peripherally acting) • • Block the alpha 1 -adrenergic receptors The SNS is not stimulated Result: DECREASED blood pressure • Stimulation of alpha 1 -adrenergic receptors causes HYPERtension • Blocking alpha 1 -adrenergic receptors causes decreased blood pressure Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Mechanism of Action Adrenergic Agents Central-Acting Adrenergics • Stimulate alpha 2 -adrenergic receptors • Sympathetic outflow from the CNS is decreased Result: decreased blood pressure Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Adrenergic Agents Central-Acting Adrenergics • clonidine (Catapres) • methyldopa (Aldomet) (drug of choice for hypertension in pregnancy) Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Mechanism of Action Adrenergic Agents Adrenergic Neuronal Blockers (peripherally acting) • Inhibit release of norepinephrine • Also deplete norepinephrine stores • SNS (peripheral adrenergic nerves) is not stimulated Result: decreased blood pressure Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Adrenergic Agents Adrenergic Neuronal Blockers (peripherally acting) • reserpine • guanadrel (Hylorel) • guanethidine (Ismelin) Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Adrenergic Agents Therapeutic Uses • Alpha 1 blockers (peripherally acting) – Treatment of hypertension – Relief of symptoms of BPH – Management of of severe CHF when used with cardiac glycosides and diuretics Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Adrenergic Agents Therapeutic Uses • Central-Acting Adrenergics – Treatment of hypertension, either alone or with other agents – Usually used after other agents have failed due to side effects – Also may be used for treatment of severe dysmenorrhea, menopausal flushing, glaucoma – Clonidine is useful in the management of withdrawal symptoms in opioid- or nicotinedependent persons Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Adrenergic Agents Therapeutic Uses • Adrenergic neuronal blockers (peripherally acting) – Treatment of hypertension, either alone or with other agents – Seldom used because of frequent side effects Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Adrenergic Agents Side Effects Most common: sedation dry mouth drowsiness constipation Other: headaches rash (palpitations) sleep disturbances nausea cardiac disturbances HIGH INCIDENCE OF ORTHOSTATIC HYPOTENSION Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Categories Angiotensin-Converting Enzyme Inhibitors (ACE Inhibitors) • Large group of safe and effective drugs • Often used as first-line agents for CHF and hypertension • May be combined with a thiazide diuretic or calcium channel blocker Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Mechanism of Action ACE Inhibitors RAAS: Renin Angiotensin-Aldosterone System • When the enzyme angiotensin I is converted to angiotensin II, the result is potent vasoconstriction and stimulation of aldosterone • Result of vasoconstriction: increased systemic vascular resistance and increased afterload • Therefore, increased BP Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Mechanism of Action ACE Inhibitors • Aldosterone stimulates water and sodium resorption. • Result: increased blood volume, increased preload, and increased B Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Mechanism of Action ACE Inhibitors • ACE Inhibitors block the angiotensin-converting enzyme, thus preventing the formation of angiotensin II. • Also prevent the breakdown of the vasodilating substance, bradykinin Result: decreased systemic vascular resistance (afterload), vasodilation, and therefore, decreased blood pressure Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents ACE Inhibitors • captopril (Capoten) • Short half-life, must be dosed more frequently than others • enalapril (Vasotec) • The only ACE inhibitor available in oral and parenteral forms • lisinopril (Prinivil and Zestril) and quinapril (Accupril) • Newer agents, long half-lives, once-a-day dosing • Several other agents available Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Therapeutic Uses ACE Inhibitors • Hypertension • CHF (either alone or in combination with diuretics or other agents) • Slows progression of left ventricular hypertrophy after an MI • Renal protective effects in patients with diabetes Drugs of choice in hypertensive patients with CHF Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Side Effects ACE Inhibitors • Fatigue Dizziness • Headache Mood changes • Impaired taste Dry, nonproductive cough, reverses when therapy is stopped NOTE: first-dose hypotensive effect may occur!! Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Categories Angiotensin II Receptor Blockers (A II Blockers or ARBs) • Newer class • Well-tolerated • Do not cause coughing Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Mechanism of Action Angiotensin II Receptor Blockers • Allow angiotensin I to be converted to angiotensin II, but block the receptors that receive angiotensin II • Block vasoconstriction and release of aldosterone Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Angiotensin II Receptor Blockers • losartan (Cozaar) • eposartan (Teveten) • valsartan (Diovan) • irbesartan (Avapro) • candesartan (Atacand) • telmisartan (Micardis) Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Therapeutic Uses Angiotensin II Receptor Blockers • Hypertension • Adjunctive agents for the treatment of CHF • May be used alone or with other agents such as diuretics Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Side Effects Angiotensin II Receptor Blockers • Upper respiratory infections • Headache • May cause occasional dizziness, inability to sleep, diarrhea, dyspnea, heartburn, nasal congestion, back pain, fatigue Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Mechanism of Action Calcium Channel Blockers • Cause smooth muscle relaxation by blocking the binding of calcium to its receptors, preventing muscle contraction • This causes decreased peripheral smooth muscle tone, decreased systemic vascular resistance • Result: decreased blood pressure Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents Calcium Channel Blockers • Benzothiazepines: – diltiazem (Cardizem, Dilacor) • Phenylalkamines: – verapamil (Calan, Isoptin) • Dihydropyridines: – amlodipine (Norvasc), bepridil (Vascor), nicardipine (Cardene) – nifedipine (Procardia), nimodipine (Nimotop) Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Side Effects Calcium Channel Blockers • Cardiovascular – hypotension, palpitations, tachycardia • Gastrointestinal – constipation, nausea • Other – rash, flushing, peripheral edema, dermatitis Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Diuretics • Decrease the plasma and extracellular fluid volumes • Results: decreased preload decreased cardiac output decreased total peripheral resistance • Overall effect: decreased workload of the heart, and decreased blood pressure Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Mechanism of Action Vasodilators • Directly relaxes arteriolar smooth muscle • Result: decreased systemic vascular response, decreased afterload, and PERIPHERAL VASODILATION Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents Vasodilators • diazoxide (Hyperstat) • hydralazine HCl (Apresoline) • minoxidil (Loniten, Rogaine) • sodium nitroprusside (Nipride, Nitropress) Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Therapeutic Uses Vasodilators • Treatment of hypertension • May be used in combination with other agents • Sodium nitroprusside and diazoxide IV are reserved for the management of hypertensive emergencies Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Side Effects Vasodilators • Hydralazine: – dizziness, headache, anxiety, tachycardia, nausea and vomiting, diarrhea, anemia, dyspnea, edema, nasal congestion • Sodium nitroprusside: – bradycardia, hypotension, possible cyanide toxicity Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Nursing Implications • Before beginning therapy, obtain a thorough health history and head-to-toe physical examination. • Assess for contraindications to specific antihypertensive agents. • Assess for conditions that require cautious use of these agents. Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Nursing Implications • Educate patients about the importance of not missing a dose and taking the medications exactly as prescribed. • Patients should never double up on doses if a dose is missed; check with physician for instructions on what to do if a dose is missed. • Monitor BP during therapy. Instruct patients to keep a journal of regular BP checks. Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Nursing Implications • Instruct patients that these drugs should not be stopped abruptly, as this may cause a rebound hypertensive crisis, and perhaps lead to CVA. • Oral forms should be given with meals so that absorption is more gradual and effective. • Administer IV forms with extreme caution and use an IV pump. Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Nursing Implications • Remind patients that medications is only part of therapy. Encourage patients to watch their diet, stress level, weight, and alcohol intake. • Patients should avoid smoking and eating foods high in sodium. • Encourage supervised exercise. Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Nursing Implications • Instruct patients to change positions slowly to avoid syncope from postural hypotension. • Patients should report unusual shortness of breath; difficulty breathing; swelling of the feet, ankles, face, or around the eyes; weight gain or loss; chest pain; palpitations; or excessive fatigue. Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Nursing Implications • Men taking these agents may not be aware that impotence is an expected effect. This may influence compliance with drug therapy. • If patients are experiencing serious side effects, or believe that the dose or medication needs to be changed, they should contact their physician immediately. Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Nursing Implications • Hot tubs, showers, or baths; hot weather; prolonged sitting or standing; physical exercise; and alcohol ingestion may aggravate low blood pressure, leading to fainting and injury. Patients should sit or lie down until symptoms subside. • Patients should not take any other medications, including OTC drugs, without first getting the approval of their physician. Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antihypertensive Agents: Nursing Implications • Monitor for side/adverse effects (dizziness, orthostatic hypotension, fatigue) and for toxic effects. • Monitor for therapeutic effects • Blood pressure should be maintained at less than 140/90 mm Hg Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.