Pharm 118 (Week 3) - Ch 24 Part 3

Angiotensin II Receptor Blockers :Angiotensin II Receptor Blockers (A II blockers, or ARBs) Newer class Well tolerated Do not cause a dry cough Mechanism of Action Allow angiotensin I to be converted to angiotensin II, but block the receptors that receive angiotensin II Block vasoconstriction and release of aldosterone 1


Angiotensin II Receptor Blockers :Angiotensin II Receptor Blockers losartan (Cozaar, Hyzaar) valsartan (Diovan) eprosartan irbesartan Others Indications Hypertension Adjunctive drugs for the treatment of HF May be used alone or with other drugs such as diuretics Used primarily in patients who cannot tolerate ACE inhibitors 2


Angiotensin II Receptor Blockers :Angiotensin II Receptor Blockers Adverse Effects Upper respiratory infections Headache May cause occasional dizziness, inability to sleep, diarrhea, dyspnea, heartburn, nasal congestion, back pain, fatigue Hyperkalemia much less likely to occur 3


Calcium Channel Blockers :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 and decreased systemic vascular resistance Result: decreased blood pressure 4


Calcium Channel Blockers :Calcium Channel Blockers Calcium Channel Blockers used in hypertension Diltiazem (Cardizem, Tiamate) Verapamil (Calan SR) Amlodipine (Norvasc) Nicardipine (Cardene) Nifedipine (Procardia XL) Felodipine (Plendil) Isradipine (DynaCirc) Nisoldipine (Sular) 5


Calcium Channel Blockers :Calcium Channel Blockers Adverse Effects Hypotension, palpitations, bradycardia Heart blocks Dizziness, lightheaded headache Nausea, constipation Rash, flushing, peripheral edema, dermatitis Indications Angina Hypertension Dysrhythmias Migraine headaches Raynaud’s disease 6


Vasodilators :Vasodilators Mechanism of Action Directly relax arteriolar and/or venous smooth muscle Result: decreased systemic vascular response, decreased afterload, and peripheral vasodilation Antihypertensive DrugsVasodilators diazoxide (Hyperstat) hydralazine HCl (Apresoline) minoxidil (Loniten) sodium nitroprusside (Nipride, Nitropress) 7


Nursing Implications :Nursing Implications Before beginning therapy, obtain a thorough health history and head-to-toe physical examination Assess for contraindications to specific antihypertensive drugs Assess for conditions that require cautious use of these drugs 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 8


Nursing Implications :Nursing Implications Instruct patients that these drugs should not be stopped abruptly because this may cause a rebound hypertensive crisis, and perhaps lead to stroke 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 Remind patients that medication 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 9


Nursing Implications :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 Men taking these drugs may not be aware that impotence is an expected effect. This may influence compliance with drug therapy If patients are experiencing serious adverse effects, or believe that the dose or medication needs to be changed, they should contact their physician immediately 10


Nursing Implications :Nursing Implications Educate about lifestyle changes that may be needed Weight loss Stress management Supervised exercise Dietary measures Monitor for adverse effects (dizziness, orthostatic hypotension, fatigue) and for toxic effects Monitor for therapeutic effects Blood pressure should be maintained at less than 130/90 mm Hg If a patient with hypertension also has diabetes or renal disease, the BP goal is less than130/80 mm Hg (JNC-7) 11