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 mitigate sympathetic nervous system overactivity. This medication is indicated for the management of hypertension, angina pectoris, and hemodynamic stability following myocardial infarction, offering a targeted mechanism that prioritizes patient-specific therapeutic outcomes while maintaining a well-established safety profile. Its pharmacokinetic properties allow for predictable absorption and elimination, supporting both immediate-release and extended-release formulations tailored to individual clinical requirements.

Features

• Contains metoprolol tartrate as the active pharmaceutical ingredient
• Available in immediate-release (25 mg, 50 mg, 100 mg tablets) and extended-release formulations
• Exhibits relative cardioselectivity (beta-1 adrenergic receptor antagonism)
• Rapid absorption with peak plasma concentrations occurring within 1–2 hours (immediate-release)
• Hepatic metabolism primarily via CYP2D6 isoenzyme
• Elimination half-life of approximately 3–7 hours
• White, round, scored tablets with “LOPRESSOR” debossed on one side

Benefits

• Effectively lowers systolic and diastolic blood pressure through reduced cardiac output and sympathetic outflow
• Decreases frequency of anginal episodes by lowering myocardial oxygen consumption
• Improves survival rates when administered early in acute myocardial infarction
• Reduces risk of recurrent cardiovascular events in post-infarction patients
• Provides predictable 24-hour hemodynamic control with appropriate dosing regimens
• May alleviate symptoms of sympathetic overactivation such as palpitations and anxiety

Common use

Lopressor is primarily prescribed for the management of essential hypertension, either as monotherapy or in combination with other antihypertensive agents. It is also indicated for long-term prophylaxis of angina pectoris, particularly in patients with exertional or stress-induced symptoms. In the context of acute myocardial infarction, it is used to stabilize cardiac rhythm, reduce infarct size, and prevent reinfarction when initiated early in hemodynamically stable patients. Off-label uses may include rate control in atrial fibrillation, migraine prophylaxis, and management of symptomatic anxiety with cardiovascular manifestations.

Dosage and direction

For hypertension: Initial dose is typically 50 mg twice daily (immediate-release) or 100 mg once daily (extended-release), adjusted at weekly intervals based on therapeutic response. Maintenance doses range from 100–450 mg per day in divided doses. For angina: Starting dose is 50 mg twice daily, titrated upward to a maximum of 400 mg daily. Post-myocardial infarction: Administer 50 mg every 6 hours beginning 15 minutes after last intravenous dose, continuing for 48 hours, followed by 100 mg twice daily. Always titrate gradually and individualize based on heart rate, blood pressure response, and tolerability. Tablets should be taken with or immediately following meals to enhance bioavailability.

Precautions

Monitor renal and hepatic function periodically, as severe impairment may necessitate dose adjustment. Use caution in patients with compensated heart failure, as beta-blockade may precipitate acute decompensation. Abrupt discontinuation may cause rebound hypertension, angina exacerbation, or arrhythmias; taper over 1–2 weeks. May mask signs of hypoglycemia (tachycardia, tremor) in diabetic patients. Can exacerbate symptoms in peripheral vascular disease or Raynaud’s phenomenon. Regular ophthalmologic examinations recommended due to potential reduction in tear production. Elderly patients may require lower initial doses due to altered pharmacokinetics.

Contraindications

Absolute contraindications include severe bradycardia (heart rate <45–50 bpm), second- or third-degree heart block without functioning pacemaker, cardiogenic shock, decompensated heart failure (NYHA Class IV), and sick sinus syndrome. Hypersensitivity to metoprolol or any component of the formulation prohibits use. Concurrent administration with certain calcium channel blockers (verapamil, diltiazem) is contraindicated due to additive negative chronotropic and inotropic effects. Should not be used in patients with untreated pheochromocytoma without prior alpha-blockade.

Possible side effect

Common adverse reactions (≥1%) include fatigue (10%), dizziness (10%), depression (5%), bradycardia (10%), diarrhea (5%), and dyspnea (3%). Less frequent effects include nightmares, insomnia, cold extremities, and bronchospasm in susceptible individuals. Serious but rare events include exacerbation of heart failure, heart block, severe hypotension, and hallucinations. Dermatological reactions such as rash and psoriasiform eruptions occur in <1% of patients. Reversible alopecia and libido decrease have been reported.

Drug interaction

Potent CYP2D6 inhibitors (fluoxetine, paroxetine, quinidine) may increase metoprolol concentrations. Concurrent use with other beta-blockers or calcium channel blockers may produce additive cardiovascular effects. Nonsteroidal anti-inflammatory drugs may attenuate antihypertensive effect. Concomitant digoxin use increases risk of bradycardia. Insulin and oral hypoglycemics may require dose adjustment due to masked hypoglycemic symptoms. Barbiturates and rifampin may reduce metoprolol concentrations. Clonidine withdrawal may cause exaggerated hypertension if metoprolol is continued.

Missed dose

If a dose is missed, administer as soon as remembered unless within 4 hours of next scheduled dose (for twice-daily regimen) or 8 hours (for once-daily regimen). Do not double the next dose to compensate. For extended-release formulations, take missed dose as soon as possible unless close to next dose. Maintain consistent timing to ensure stable plasma concentrations. Patients should be educated on maintaining dose regularity while avoiding excessive dosing.

Overdose

Manifestations include severe bradycardia, hypotension, heart failure, bronchospasm, hypoglycemia, and coma. Specific symptoms may progress to cardiogenic shock and cardiac arrest. Treatment involves gastric lavage if recent ingestion, followed by activated charcoal. Administer atropine 0.5–2.0 mg IV for bradycardia. Glucagon 5–10 mg IV may reverse cardiac effects. Beta-agonist infusion (isoproterenol, dobutamine) or phosphodiesterase inhibitors may be necessary. Cardiac pacing for refractory bradycardia. Hemodialysis is not effective due to high protein binding.

Storage

Store at controlled room temperature (20–25°C or 68–77°F) in original container. Protect from light, moisture, and excessive heat. Keep tightly closed and out of reach of children. Do not transfer to alternative containers that lack moisture protection. Discard any tablets showing physical deterioration or discoloration. Do not use beyond expiration date printed on packaging.

Disclaimer

This information describes the general properties of Lopressor (metoprolol tartrate) but does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider regarding any medical condition or treatment decisions. Individual patient responses may vary based on comorbidities, concomitant medications, and genetic factors. The prescribing physician should be consulted for personalized dosage adjustments and monitoring recommendations.

Reviews

“Lopressor has been instrumental in managing my post-MI patients, providing reliable rate control and reducing anginal frequency with minimal side effects when titrated appropriately.” — Cardiologist, 15 years experience

“As a clinical pharmacist, I appreciate its predictable pharmacokinetics, though I emphasize the importance of gradual titration and patient education regarding missed doses.” — PharmD, hospital practice

“My hypertensive patients on metoprolol have shown consistent BP control, though some report fatigue initially which often resolves with continued use.” — Internal Medicine Physician

“The cardioselectivity offers an advantage in patients with mild reactive airway disease, though we remain cautious with higher doses.” — Pulmonologist

“Formulation flexibility allows us to tailor therapy to individual patient needs, improving adherence and outcomes.” — Clinical researcher