Metoprolol
Classification: Antihypertensive; Beta1-selective adrenergic blocker
Uses: Hypertension, alone or with other drugs esp. diuretics.
Immediate release tablets and injection: prevention of reinfarction in MI patients who are hemodynamically stable or within 3-10 days of the acute MI.
Long term treatment of angina pectoris
Actions: Competetively blocks beta-adrenergic receptors in the heart and juxtaglomerular apparatus, decreasing influence of the sympathetic nervous system on these tissues and the excitability of the heart, decreasing cardiac output and release of renin, and lowering bp; acts in CNS to reduce sympathetic outflow and vasoconstrictor tone.
Administration and Dosage: for Hypertension: Initially, 100 mg per day PO in single or divided doses; gradually increase dosage at weekly intervals. Usual maintenance dosage is 100-450 mg/day.
Side Effects: Allergic pharyngitis, rash, fever, sore throat, laryngospasm, dizziness, vertigo, tinnitus, fatigue, emotional depression, paresthesias, sleep disturbances, hallucinations, disorientation, memory loss, slurred speech, heart failure, cardiac arrhythmias, peripheral vascular insufficiency, claudication, CVA, pulmonary edema, hypotension, Eye irritation, sweating, dry eyes, conjunctivitis, dry skin, blurred visions, Gastric pain, flatulence, constipation, diarrhea, nausea, vomitting, anorexia, ischemic colitis, retroperitoneal fibrosis, hepatomegaly, acute pancreatitis, Impotence, decreased libido, dysuria, Peyronie's disease, nocturia, frequent urination, joint pain, muscle cramp, dyspnea, cough, bronchial obstruction, nasal stuffiness, rhinitis, pharyngitis.
Nursing Implications: Contraindicated with sinus bradycardia, second or third degree heart block, cardiogenic shock, heart failure, second and third ttrimesters of pregnancy. Use cautiously with diabetes or throtoxicosis; astma or COPD; pregnancy. Take drug early in the day so sleep will not be distrubed by increased urination. Weight patient daily and record weights. Protect skin from sun and bright lights. Report rapid weight change. Monitor blood pressure, ECG, and pulse frequently during dose adjustment and periodically during therapy. Monitor frequency of prescription refulls to determine compliance. Monitor vitals and ECG every 5-15 minutes during and for several hours after parenteral administration. If heart rate <40 especially if cardiac output is also decreased, administer atropine 0.25-0.5 mg IV. MOnitor intake and output ratios and daily weights. Assess routinely for signs and symptoms of CHF: dsypnea, rales/crackles, weight gain, peripheral edemaa, jugular venous distention.
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