Isoproterenol Hydrochloride

Clinical summary

Indications and usage 1 INDICATIONS AND USAGE Isoproterenol hydrochloride injection is indicated: To improve hemodynamic status in patients in distributive shock and shock due to reduced cardiac output For bronchospasm occurring during anesthesia Isoproterenol hydrochloride injection is a beta-adrenergic agonist indicated: To improve hemodynamic status in patients in distributive shock and shock due to reduced cardiac output ( 1 ) For treatment of bronchospasm occurring during anesthesia ( 1 ) Dosage and administration 2 DOSAGE AND ADMINISTRATION Initiate isoproterenol hydrochloride injection at the lowest recommended dose and increase gradually based on patient response ( 2.2 ) Recommended initial dosage: Shock: 0.5 mcg to 5 mcg per minute as an intravenous infusion ( 2.2 ) Bronchospasm: 10 mcg to 20 mcg intravenous injection ( 2.2 ) 2.1 General Considerations Inspect visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Do not use if the injection is pinkish or darker than slightly yellow or contains a precipitate. Discard any unused portion. Diluted solution should be used immediately. Unused material should be discarded. 2.2 Recommended Dosage Dosage should generally be started at the lowest recommended dose and increased gradually based on patient response. Recommended dosage for adults with shock and hypoperfusion states: Route of Administration Preparation of Dilution † Infusion Rate †† Intravenous infusion Dilute 5 mL (1 mg) in 500 mL of 5% Dextrose Injection, USP 0.5 mcg to 5 mcg per minute (0.25 mL to 2.5 mL of diluted solution) † Concentrations up to 10 times greater have been used when limitation of volume is essential. †† Rates over 30 mcg per minute have been used in advanced stages of shock. Adjust the rate of infusion based on heart rate, central venous pressure, systemic blood pressure, and urine flow. If the heart rate exceeds 110 beats per minute, consider decreasing or temporarily discontinuing the infusion. Recommended dosage for adults with bronchospasm occurring during anesthesia: Route of Administration Preparation of Dilution Initial Dose Subsequent Dose Bolus intravenous injection Dilute 1 mL (0.2 mg) to 10 mL with Sodium Chloride Injection, USP, or 5% Dextrose Injection, USP 10 mcg to 20 mcg (0.5 mL to 1 mL of diluted solution) The initial dose may be repeated when necessary There are no well-controlled studies in children to establish appropriate dosing; however, the American Heart Association recommends an initial infusion rate of 0.1 mcg/kg/min, with the usual range being 0.1 mcg/kg/min to 1 mcg/kg/min. Warnings and cautions 5 WARNINGS AND PRECAUTIONS Cardiac arrhythmias and ischemia may be induced by isoproterenol hydrochloride ( 5.1 ) Sulfite: Isoproterenol hydrochloride contains metabisulfite, which may cause allergic reaction ( 5.2 ) 5.1 Cardiac Arrhythmias and Ischemia Isoproterenol may induce cardiac arrhythmias and myocardial ischemia in patients, especially patients with coronary artery disease, or cardiomyopathy. 5.2 Allergic Reactions associated with Sulfite Isoproterenol hydrochloride contains sodium metabisulfite, which may cause mild to severe allergic reactions including anaphylaxis or asthmatic episodes, particularly in patients with a history of allergies. However, the presence of metabisulfite in this product should not preclude its use for treatment in emergency situations, even if the patient is sulfite-sensitive, as the alternatives to using isoproterenol in a life- threatening situation may not be satisfactory. Drug interactions 7 DRUG INTERACTIONS Table 1. Clinically Relevant Interactions with Isoproterenol Epinephrine Clinical Impact Both drugs are direct cardiac stimulants, and their combined effects may induce serious arrhythmias upon simultaneous administration. Intervention Isoproterenol hydrochloride injection and epinephrine should not be administered simultaneously. Drugs that may potentiate clinical response of Isoproterenol Clinical Impact The effects of isoproterenol may be potentiated by tricyclic antidepressants, monoamine oxidase inhibitors, levothyroxine sodium,andcertainantihistamines,notablychlorpheniramine, tripelennamine,anddiphenhydramine. Intervention Monitor hemodynamic parameters in patients who concurrently are taking tricyclic antidepressants, monoamine oxidase inhibitors, levothyroxine sodium and certain antihistamines. Adjust doses appropriately. Drugs that may reduce clinical response of Isoproterenol Clinical Impact The cardiostimulating and bronchodilating effects of isoproterenol are antagonized by beta-adrenergic blocking drugs, such as propranolol. Intervention Monitor for hemodynamic response and relief of bronchospasm and adjust dose appropriately. Do not administer isoproterenol hydrochloride and epinephrine simultaneously due to combined effects may induce serious arrhythmias ( 7 ) Concomitant use of tricyclic antidepressants, monoamine oxidase inhibitors,