Metoprolol

Clinical summary

Indications and usage 1 INDICATIONS AND USAGE Metoprolol tartrate injection is indicated in the treatment of definite or suspected acute myocardial infarction in hemodynamically stable patients to reduce cardiovascular mortality when used in conjunction with oral metoprolol maintenance therapy. Metoprolol tartrate injection is a beta - adrenergic receptor inhibitor indicated for the treatment of definite or suspected acute myocardial infarction in hemodynamically stable patients to reduce cardiovascular mortality when used in conjunction with oral metoprolol maintenance therapy ( 1 ). Dosage and administration 2 DOSAGE AND ADMINISTRATION Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Initiate treatment in a coronary care or similar unit immediately after the patient's hemodynamic condition has stabilized. Begin treatment in this early phase with the intravenous administration of three bolus injections of 5 mg of metoprolol tartrate injection each; give the injections at approximately 2-minute intervals. During the intravenous administration of metoprolol tartrate injection, monitor blood pressure, heart rate, and electrocardiogram. Transition to Oral Metoprolol: Following administration of metoprolol tartrate injection, transition patients to an oral formulation of metoprolol. See prescribing information for oral metoprolol for dose selection. • Initiate therapy in a coronary care or similar unit immediately after the patients hemodynamic condition has stabilized ( 2 ). • Begin treatment with an intravenous administration of three bolus injections of 5 mg each, at approximately 2-minute intervals. Monitor blood pressure, heart rate and electrocardiogram ( 2 ). • Following administration of metoprolol tartrate injection, transition the patient to an oral formulation of metoprolol ( 2 ). Warnings and cautions 5 WARNINGS AND PRECAUTIONS • Worsening cardiac failure may occur. ( 5.1 ) • Bronchospastic Disease: Avoid beta blockers. ( 5.2 ) • Pheochromocytoma: First initiate therapy with an alpha blocker. ( 5.3 ) • May aggravate symptoms of arterial insufficiency. ( 5.4 ) 5.1 Bradycardia Bradycardia, including sinus pause, heart block, and cardiac arrest have occurred with the use of metoprolol tartrate injection. Patients with first-degree atrioventricular block, sinus node dysfunction, or conduction disorders may be at increased risk. Monitor heart rate and rhythm in patients receiving metoprolol tartrate injection. If severe bradycardia develops, reduce or stop metoprolol tartrate injection. 5.2 Heart Failure Worsening cardiac failure may occur during metoprolol use. If such symptoms occur, increase diuretics and restore clinical stability before administering the next dose of metoprolol [see Dosage and Administration ( 2 )]. Such episodes do not preclude subsequent successful titration of oral metoprolol. 5.3 Bronchospastic Disease PATIENTS WITH BRONCHOSPASTIC DISEASES, IN GENERAL, SHOULD NOT RECEIVE BETA-BLOCKERS because they can exacerbate bronchospasm. Because of its relative beta 1 cardio-selectivity, however, metoprolol may be used in patients with bronchospastic disease for initial treatment of myocardial infarction. Bronchodilators, including beta 2 -agonists, should be readily available or administered concomitantly [see Dosage and Administration ( 2 )]. 5.4 Pheochromocytoma If metoprolol tartrate is used in the setting of pheochromocytoma, it should be given in combination with an alpha blocker, and only after the alpha blocker has been initiated. Administration of beta-blockers alone in the setting of pheochromocytoma has been associated with a paradoxical increase in blood pressure due to the attenuation of beta-mediated vasodilatation in skeletal muscle. 5.5 Hypoglycemia Beta‐blockers may prevent early warning signs of hypoglycemia, such as tachycardia, and increase the risk for severe or prolonged hypoglycemia at any time during treatment, especially in patients with diabetes mellitus or children and patients who are fasting (i.e., surgery, not eating regularly, or are vomiting). If severe hypoglycemia occurs, patients should be instructed to seek emergency treatment. 5.6 Peripheral Vascular Disease Beta-blockers can precipitate or aggravate symptoms of arterial insufficiency in patients with peripheral vascular disease. Drug interactions 7 DRUG INTERACTIONS • Catecholamine-depleting drugs may have an additive effect when given with beta-blocking agents. ( 7.1 ) • Patients may be unresponsive to the usual doses of epinephrine used to treat allergic reaction. ( 7.2 ) • CYP2D6 Inhibitors are likely to increase metoprolol concentration. ( 7.3 ) • Concomitant use of glycosides, clonidine, and diltiazem and verapamil with beta-blockers can increase the risk of bradycardia. ( 7.4 ) • Beta-blockers including metoprolol, may exacerbate the rebound hypertension that can follow the withdrawal