Lopressor (metoprolol tartrate) is a cardioselective beta-1 adrenergic receptor blocking agent, representing a cornerstone in modern cardiovascular pharmacotherapy. It is specifically engineered to antagonize catecholamine-induced tachycardia, reduce myocardial oxygen demand, and modulate sympathetic nervous system overactivity with high receptor specificity. Clinically validated through decades of use and extensive research, Lopressor offers physicians a reliable, titratable option for managing hypertension, angina pectoris, and post-myocardial infarction scenarios. Its well-characterized pharmacokinetic profile allows for predictable therapeutic outcomes, making it a first-line agent in evidence-based treatment protocols aimed at reducing cardiovascular morbidity and mortality.

Features

• Contains metoprolol tartrate as the active pharmaceutical ingredient
• Available in 25 mg, 50 mg, and 100 mg scored tablets for precise dosing
• Selective beta-1 adrenergic receptor blockade with minimal beta-2 activity at therapeutic doses
• Rapid absorption with peak plasma concentrations occurring within 1–2 hours post-administration
• Hepatic metabolism primarily via CYP2D6 isoenzyme, producing active metabolites
• Elimination half-life of approximately 3–7 hours, permitting twice-daily dosing
• White, round, film-coated tablets with distinct imprints for strength identification

Benefits

• Effectively lowers blood pressure through reduced cardiac output and sympathetic outflow
• Decreases frequency and severity of angina episodes by lowering myocardial oxygen demand
• Improves survival rates when administered early in acute myocardial infarction
• Reduces risk of recurrent infarction and sudden cardiac death in post-MI patients
• Provides predictable hemodynamic effects with dose-dependent response
• Allows for flexible dosing titration based on individual patient tolerance and response

Common use

Lopressor is indicated for the management of hypertension, either as monotherapy or in combination with other antihypertensive agents. It is employed in the long-term treatment of chronic stable angina pectoris to reduce exercise-induced tachycardia and myocardial ischemia. Following acute myocardial infarction, it is used to reduce cardiovascular mortality, particularly in preventing sudden death. Off-label uses include rate control in atrial fibrillation/flutter, symptom management in hyperthyroidism, and prophylactic treatment for migraine headaches. It may also be utilized in heart failure with reduced ejection fraction when combined with other guideline-directed medical therapies.

Dosage and direction

For hypertension: Initial dose is 50 mg twice daily, which may be increased at weekly intervals to a maximum of 400 mg daily in divided doses. For angina: Usual dosage is 50 mg twice daily, titrated upward until optimal clinical response is achieved, not to exceed 400 mg per day. In myocardial infarction: Early treatment involves three IV bolus injections of 5 mg each at 2-minute intervals, followed by 50 mg orally every 6 hours for 48 hours, then maintenance dosing of 100 mg twice daily. Tablets should be taken with or immediately following meals to enhance bioavailability and minimize peak concentration variations. Dosage adjustments are required in hepatic impairment and in poor CYP2D6 metabolizers.

Precautions

Abrupt discontinuation may precipitate angina exacerbation, myocardial infarction, or ventricular arrhythmias; taper gradually over 1–2 weeks. Use cautiously in patients with compensated heart failure, as beta-blockade may precipitate acute decompensation. May mask tachycardia occurring with hypoglycemia in diabetic patients and signs of hyperthyroidism. Can cause bronchospasm in patients with reactive airway disease despite relative cardioselectivity. May reduce exercise tolerance and blunt cardiovascular response to strenuous activity. Use with caution in peripheral vascular disease due to potential reduction in peripheral blood flow. Regular monitoring of heart rate, blood pressure, and clinical status is recommended during therapy initiation and dose adjustments.

Contraindications

Severe bradycardia (heart rate <45–50 beats per minute), second- or third-degree heart block without functioning pacemaker, cardiogenic shock, decompensated heart failure, sick sinus syndrome, and hypersensitivity to metoprolol or any component of the formulation. Absolute contraindication in patients with asthma or history of bronchospasm requiring regular treatment. Should not be used concurrently with other beta-blocking agents due to additive effects. Contraindicated in patients with pheochromocytoma unless alpha-blockade has been established first.

Possible side effect

Most common adverse reactions include fatigue (approximately 10%), dizziness (5–10%), depression (5%), diarrhea (5%), and bradycardia (3–5%). Less frequently reported: shortness of breath, cold extremities, Raynaud’s phenomenon, insomnia, nightmares, and visual disturbances. Gastrointestinal effects may include nausea, vomiting, or constipation. Rare but serious side effects include heart failure exacerbation, bronchospasm, severe bradycardia, AV block, hypotension, and exacerbation of peripheral artery disease. Psychiatric effects including hallucinations and memory impairment have been reported in elderly patients. Reversible alopecia and Peyronie’s disease have been rarely associated with beta-blocker therapy.

Drug interaction

Concurrent use with calcium channel blockers (verapamil, diltiazem) may produce additive bradycardia and AV conduction disturbances. Potentiates hypotensive effects of other antihypertensive agents. CYP2D6 inhibitors (quinidine, fluoxetine, paroxetine) may significantly increase metoprolol concentrations. May antagonize effects of beta-agonists used for bronchospasm. Concurrent use with clonidine may produce paradoxical hypertension upon clonidine withdrawal. Digoxin levels may increase when co-administered with metoprolol. Nonsteroidal anti-inflammatory drugs may attenuate antihypertensive effect. May alter insulin requirements and mask hypoglycemic symptoms in diabetic patients.

Missed dose

If a dose is missed, it should be taken as soon as remembered unless it is nearly time for the next scheduled dose. In that case, the missed dose should be skipped and the regular dosing schedule resumed. Patients should not double the next dose to make up for a missed administration, as this may increase the risk of adverse effects such as bradycardia or hypotension. Consistency in dosing timing is important for maintaining stable plasma concentrations and therapeutic effect, particularly for angina prophylaxis.

Overdose

Manifestations include severe bradycardia, hypotension, heart failure, bronchospasm, hypoglycemia, and impaired consciousness. Cardiovascular effects may progress to cardiogenic shock and asystole. Management involves gastric lavage if ingestion was recent and supportive care including IV fluids for hypotension. Bradycardia may respond to atropine 0.5–1 mg IV; refractory cases may require isoproterenol infusion or cardiac pacing. Glucagon (5–10 mg IV) has been used successfully to reverse myocardial depression. Beta-agonist bronchodilators (with caution) for bronchospasm. Hemodialysis is not effective due to extensive protein binding. Continuous cardiac and blood pressure monitoring is essential until stabilization.

Storage

Store at controlled room temperature 20–25°C (68–77°F) with excursions permitted between 15–30°C (59–86°F). Protect from moisture, light, and excessive heat. Keep in original container with tight closure to maintain stability. Do not transfer to other containers that may not provide adequate protection. Keep out of reach of children and pets. Properly discard any tablets that show signs of physical deterioration, discoloration, or are beyond the expiration date printed on packaging.

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. Individual patient response to Lopressor may vary based on genetic factors, comorbidities, and concomitant medications. Prescribing decisions should be made by qualified healthcare professionals based on comprehensive patient assessment. The full prescribing information should be consulted before initiating therapy. Patients should not adjust dosage or discontinue medication without medical supervision.

Reviews

Clinical trials consistently demonstrate Lopressor’s efficacy in reducing blood pressure by 10–15 mmHg systolic and 5–10 mmHg diastolic with twice-daily dosing. In the Gothenburg Metoprolol Trial, mortality was reduced by 36% in post-MI patients treated with metoprolol. Angina studies show a 30–40% reduction in exercise-induced ischemia and nitrate consumption. Real-world evidence supports maintained efficacy over long-term treatment with appropriate dose titration. Most cardiologists report predictable response and favorable tolerability profile when initiated at appropriate doses in properly selected patients.