Antihypertensive Pharmacologic Agents NUR133 Lecture #11 K Burger, MSEd, MSN, RN, CNE Referenced from: Lilley et al (2005) Pharmacology and the nursing process (4 th ed). Elsevier

Categories Adrenergic agents -Alpha blockers -Beta blockers -Alpha/Beta blockers Angiotensin-converting enzyme inhibitors Angiotensin II receptor blockers Calcium channel blockers Vasodilators Diuretics

Adrenergic Agents Alpha Blockers (peripherally acting) Prazosin (Minipress) Blocks norepinephrine at receptor sites Sympathetic Nervous System not stimulated Blood vessel dilation results in decreased BP Alpha Blockers (centrally acting) Clonidine (Catapres) Reduces norepinephrine production Sympathetic Nervous System not stimulated Blood vessel dilation results in decreased BP

Adrenergic Agents Beta Blockers atenolol (Tenormin) metoprolol (Lopressor) propranolol (Inderal) Block SNS stimulation of heart; reduces SA node activity Reduces ventricular contraction rate Reduction in cardiac output results in lower BP Also used as: Antidysrhythmic, Antianginal

Adrenergic Agents Alpha / Beta Blocker Combination Carvedilol ( Coreg ) Dual antihypertensive effect on both CO and SVR Alpha blocker promotes vasodilation; decreased SVR Beta blocker reduces heart rate; decreased CO Overall effect = decreased BP

Adrenergic Agents Nursing Implications Orthostatic hypotension common;take bedtime Other side effects: fatigue, dizziness, sedation, constipation Potentiates CNS depressants (Alcohol/Opiods) Abrupt withdrawal of central alpha blocker causes rebound hypertension Less side effects with peripheral acting and/or combination adrenergics Monitor HR =>60 for beta blockers

Angiotensin-Converting Enzyme Inhibitors ACE Inhibitors Inhibit the conversion of Angiotensin I to Angiotensin II resulting in: Vasodilation,decreased SVR, decreased BP Decreased aldosterone,diuresis,decreased SVR&BP May be combined with a thiazide diuretic or calcium channel blocker Safe and effective; often used as first line Rx Used also for: CHF, post MI to stop LVH progress Renal protective effects in patients with diabetes

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 Newer agents, long half-lives, once-a-day dosing

ACE Inhibitors Nursing Implications Dry, nonproductive cough common Other side effects: fatigue,dizziness,headache, mood changes First-dose hypotensive effect may occur Additive effects when given with diuretics or other antihypertensives Antagonistic effects when given with NSAIDs If given with K supplement may cause hyperK

Angiotensin II Receptor Blockers ARBs Losartan ( Cozaar ) Valsartan ( Diovan ) Block the binding of Angiotensin II to AT1 receptors on vessels & adrenal gland thereby: - promoting vasodilation / lower aldosterone - decreased SVR and decreased BP Newer class and well-tolerated

ARB Nursing Implications Common side effects: Upper respiratory infection Headache Less likely to cause hyperkalemia (unlike ACE) Can be used in pts who cannot tolerate ACE Rx Do not cause coughing Used cautiously in geriatric pts and impaired renal function

Calcium Channel Blockers CCBs Diltiazem (Cardizem) Verapamil ( Calan ) Nifedipine ( Procardia ) Cause smooth muscle relaxation by blocking the binding of calcium to its receptors, preventing muscle contraction This causes decreased peripheral smooth muscle tone, decreased SVR and BP Slows cardiac conduction; decreases HR&CO&BP Also used as : antidysrythmic, antianginal

Calcium Channel Blockers Nursing Implications Considered safe with limited side-effects First line drug choice More effective in geriatric and African-American patients Possible side effects: hypotension, dysrythmias, constipation, nausea, rash,peripheral edema, dermatitis

Vasodilators hydralazine HCl (Apresoline) sodium nitroprusside (Nipride, Nitropress) Directly relaxes arteriolar smooth muscle vasodilation; decreased SVR; decreased BP May be used in combination with other agents Sodium nitroprusside is reserved for the management of hypertensive emergencies

Vasodilators Nursing Implications Hydralazine Side Effects: dizziness, headache, anxiety, tachycardia Sodium Nitroprusside Side Effects: bradycardia, hypotension Controlled administration/IV infusion pump

Antihypertensive Agents General Nursing Implications Educate patients about the importance of not missing a dose, taking the medications exactly as prescribed, never doubling up on doses, and not stopping abruptly Patients should not take any OTC drugs without first checking with MD PO meds should be taken with meals Educate patient on concurrent lifestyle modifications: Diet, Exercise, Stress Reduction Instruct patients on how to monitor their own BP

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.

Antihypertensive Agents General Nursing Implications Instruct patients to change positions slowly Hot showers, tubs, weather, exercise, alcohol, prolonged sitting/standing may cause hypotension, dizziness, fainting Patients should report: SOB, dyspnea, peripheral and/or angioedema, excessive weight gain, chest pain, palpitations Men may experience impotence as expected SE

Diuretics Main classifications: Thiazide and thiazide-like Loop Potassium-sparing Others: Osmotic Carbonic Anhydrase Inhibitors

Thiazide Diuretics Hydrochlorothiazide ( HydroDIURIL ) Inhibits Na reabsorption at distal tubule resulting in diuresis; decreased SVR & BP Also acts to relax arterioles;decrease SVR First line medication regimen for HTN Safe for most patients; inexpensive Often used in combination w/ other drugs

Loop Diuretics Furosemide (Lasix) Blocks Cl and Na reabsorption at Loop of Henle resulting in diuresis; decreased SVR and decreased BP Stimulate prostaglandins; vasodilation of renal, lung, system vessels Rapid onset and most potent diuretic Can be given once daily Effective even in renal impaired patients

Thiazide and Loop Diuretics Nursing Implications Monitor K levels closely for hypokalemia Teach patient to eat high K foods Cross allergies may exist to sulfonamides Concurrent digoxin Rx may lead to digoxin toxicity NSAIDS may decrease diuretic effect Concurrent antiglycemic Rx may lead to hyperglycemia

Potassium-sparing Diuretics Spironlactone ( Aldactone ) Works in the collecting duct Binds and blocks aldactone receptors resulting in blocked Na water reabsorption; decreased SVR and BP Considered a weak diuretic Often used in conjunction with more potent K depleting diuretics

Potassium-sparing Diuretic Nursing Implications Monitor K levels closely for hyperkalemia Especially with renal impairment, use of potassium supplements, or ACE drugs May cause gynecomastia, amenorrhea, and post-menopausal bleeding Other side effects: dizziness, ha, cramps, nausea,diarrhea.

Diuretics General Nursing Implications Instruct patient to take early in the day to avoid sleep disturbances Geriatric patients more sensitive to fluid balance changes; caution for postural hypotension Monitor weights, potassium levels as well as Na and Cl Instruct patients to notify MD if ill with vomiting and/or diarrhea