Betaloc ZOK Metoprolol Succinate Sustained‑Release Tablets

1. Indications and Usage
Hypertension: Indicated for the treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions.
Heart Failure: Indicated for the treatment of stable, symptomatic heart failure with reduced ejection fraction, as an adjunct to standard heart failure therapy.
Angina Pectoris: Indicated for the management of chronic stable angina pectoris.
2. Dosage and Administration
Hypertension: The usual initial dosage is 25 to 100 mg daily in a single dose. Adjust dosage at weekly (or longer) intervals until optimum blood pressure reduction is achieved.
Heart Failure: Therapy should be initiated at a low dose (e.g., 11.875 mg or 23.75 mg once daily) and titrated up gradually every 2 weeks as tolerated to the target maintenance dose.
Administration: Should be taken regularly and continuously, preferably with or immediately following meals. The extended-release tablets should be swallowed whole and must not be chewed, crushed, or divided.
3. Mechanism of Action
Beta-1 Selective Blockade: Metoprolol succinate is a beta-1-selective (cardioselective) adrenoceptor blocking agent. This preferential effect is not absolute, however, and at higher plasma concentrations, it also inhibits beta-2-adrenergic receptors.
Cardiovascular Effects: By blocking beta-1 receptors in the heart, it decreases heart rate, myocardial contractility, and cardiac output, thereby reducing myocardial oxygen demand and blood pressure.
4. Safety and Warnings
Abrupt Cessation of Therapy: Following abrupt cessation of therapy with certain beta-blocking agents, exacerbations of angina pectoris and, in some cases, myocardial infarction have occurred. Dosage should be gradually reduced over 1 to 2 weeks.
Contraindications: Contraindicated in patients with severe bradycardia, second- or third-degree heart block, cardiogenic shock, decompensated heart failure, and sick sinus syndrome (unless a functioning pacemaker is present).
Worsening Heart Failure: Transient worsening of heart failure may occur during titration. If this happens, the dose should be reduced or temporarily discontinued.
5. Adverse Reactions and Clinical Research
Adverse Reactions: The following adverse reactions are described in labeling: Worsening angina or myocardial infarction, worsening heart failure, and severe bradycardia. Common side effects include fatigue, dizziness, and depression.
Overdosage: Signs and symptoms of overdosage may lead to severe bradycardia, hypotension, and cardiogenic shock. Clinical presentation can also include atrioventricular block and heart failure.
Clinical Studies: In a double-blind study, 1,092 patients with mild-to-moderate hypertension were randomized to once-daily metoprolol succinate extended-release tablets (25, 100, or 400 mg), demonstrating significant 24-hour blood pressure control.
6. Drug Interactions
Catecholamine Depleting Drugs: Catecholamine-depleting drugs (e.g., reserpine, monoamine oxidase (MAO) inhibitors) may have an additive effect when given with beta-blocking agents. Patients should be closely observed for signs of hypotension or bradycardia.
Other Cardiovascular Agents: Concomitant use with calcium channel blockers, antiarrhythmics, or other antihypertensives may potentiate hypotensive and negative chronotropic effects.
7. Pharmaceutical Information
Active Ingredient: Metoprolol Succinate.
Dosage Forms and Strengths: Available as extended-release tablets containing 23.75 mg, 47.5 mg, 95 mg, or 190 mg of metoprolol succinate (equivalent to 25 mg, 50 mg, 100 mg, or 200 mg of metoprolol tartrate).
Appearance: White to off-white color, oval or round shaped, biconvex coated tablets.
Storage: Store at controlled room temperature, protected from moisture and light.