metoprolol

Drug Name

Generic Name :  metoprolol , metoprolol succinate , metoprolol tartrate

Brand Name: Apo-Metoprolol (CAN), Betaloc (CAN), Lopressor, Novo-metoprol (CAN), Nu-Metop (CAN) ,Toprol-XL ,Lopressor Injection

Classification: Beta1-selective adrenergic blocker, Antihypertensive

Pregnancy Category C 

Dosage & Route

Available forms : Tablets—50, 100 mg; ER tablets—25, 50, 100, 200 mg; injection—1 mg/mL

ADULTS
  • Hypertension: Initially, 100 mg/day PO in single or divided doses; gradually increase dosage at weekly intervals. Usual maintenance dose is 100–450 mg/day.
  • Angina pectoris: Initially, 100 mg/day PO in two divided doses; may be increased gradually, effective range 100–400 mg/day.
  • MI, early treatment: Three IV bolus doses of 5 mg each at 2-min intervals with careful monitoring. If these are tolerated, give 50 mg PO 15 min after the last IV dose and q 6 hr for 48 hr. Thereafter, give a maintenance dosage of 100 mg PO bid. Reduce initial PO doses to 25 mg, or discontinue in patients who do not tolerate the IV doses.
  • MI, late treatment: 100 mg PO bid as soon as possible after infarct, continuing for at least 3 mo and possibly for 1–3 yr.
ER tablets
  • Hypertension: 25–100 mg/day PO as one dose; may increase at weekly intervals to a maximum of 400 mg/day..
  • Angina: 100 mg/day PO as one dose.
  • CHF: 12.5–25 mg/day Toprol-XL for 2 wk; may then be increased by 25 mg every 2 wk to a maximum of 200 mg.
PEDIATRIC PATIENTS
  • Safety and efficacy not established.
Therapeutic actions
  • Metoprolol selectively inhibits β-adrenergic receptors but has little or no effect on β2-receptors except in high doses. It has no membrane-stabilising nor intrinsic sympathomimetic activity.
Indications
  • Hypertension, alone or with other drugs, especially 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
  • Toprol-XL only: Treatment of stable, symptomatic CHF of ischemic, hypertensive, or cardiomyopathic origin
Adverse effects
  • Bradycardia, hypotension, arterial insufficiency, chest pain, CHF, edema, palpitation, syncope, gangrene; dizziness, fatigue, depression, confusion, headache, insomnia, short-term memory loss, nightmares, somnolence; pruritus, rash, increased psoriasis, reversible alopecia; sexual dysfunction/impotence, Peyronie’s disease; diarrhoea, constipation, flatulence, GI pain, heartburn, nausea, xerostomia; agranulocytosis (rare); musculoskeletal pain; blurred vision, dry eyes, oculomucocutaneous syndrome; tinnitus; dyspnea, bronchospasm, wheezing, rhinitis; cold extremities.
  • Potentially Fatal: Heart failure, heart block, bronchospasm.
Contraindications
  • 2nd or 3rd degree AV block; sick sinus syndrome; decompensated heart failure; clinically relevant sinus bradycardia. Severe peripheral arterial circulatory disorders. Cardiogenic shock. Asthma. Phaeochromocytoma (without α-blockade), systolic BP <100 mmHg. Metabolic acidosis. Pregnancy (2nd and 3rd trimesters).
Nursing considerations
Assessment
  • History: Sinus bradycardia (HR < 45 beats/min), second- or third-degree heart block (PR interval > 0.24 sec), cardiogenic shock, CHF, systolic BP < 100 mm Hg; diabetes or thyrotoxicosis; asthma or COPD; lactation, pregnancy
  • Physical: Weight, skin condition, neurologic status, P, BP, ECG, respiratory status, renal and thyroid function tests, blood and urine glucose
Interventions
  • WARNING: Do not discontinue drug abruptly after long-term therapy (hypersensitivity to catecholamines may have developed, causing exacerbation of angina, MI, and ventricular arrhythmias). Taper drug gradually over 2 wk with monitoring.
  • Ensure that patient swallows the ER tablets whole; do not cut, crush, or chew. Toprol XL tablets may be divided at the score; divided tablets should be swallowed whole, not crushed or chewed.
  • Consult physician about withdrawing drug if patient is to undergo surgery (controversial).
  • Give oral drug with food to facilitate absorption.
  • Provide continual cardiac monitoring for patients receiving IV metoprolol.
Teaching points
  • Do not stop taking this drug unless instructed to do so by a health care provider.
  • Swallow the extended-release tablets whole; do not cut, crush, or chew them. If using Toprol XL, you can divide the tablets at the score; divided tablets must be swallowed whole, not crushed or chewed.
  • You may experience these side effects: Dizziness, drowsiness, light-headedness, blurred vision (avoid driving or dangerous activities); nausea, loss of appetite (eat frequent small meals); nightmares, depression (discuss change of medication); sexual impotence.
  • Report difficulty breathing, night cough, swelling of extremities, slow pulse, confusion, depression, rash, fever, sore throat.