Overview
11 DESCRIPTION Isoproterenol hydrochloride, USP is 3,4-Dihydroxy-α-[(isopropylamino)methyl] benzyl alcohol hydrochloride, a synthetic sympathomimetic amine that is structurally related to epinephrine but acts almost exclusively on beta receptors. The molecular formula is C 11 H 17 NO 3 • HCl. It has a molecular weight of 247.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Isoproterenol is a potent nonselective beta-adrenergic agonist with very low affinity for alpha-adrenergic receptors. 12.2 Pharmacodynamics Intravenous infusion of isoproterenol in man lowers peripheral vascular resistance, primarily in skeletal muscle but also in renal and mesenteric vascular beds. Diastolic pressure falls. Renal blood flow is decreased in normotensive subjects but is increased markedly in shock. Systolic blood pressure may remain unchanged or rise, although mean arterial pressure typically falls. Cardiac output is increased because of the positive inotropic and chronotropic effects of the drug in the face of diminished peripheral vascular resistance.
Indications
- 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 )
Common Doses
- 0.5 mcg
- 5 mcg
- 10 mcg
- 20 mcg
Dosage
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.
Contraindications
- 4 CONTRAINDICATIONS Isoproterenol hydrochloride injection is contraindicated in patients with: tachycardia ventricular arrhythmias angina pectoris Isoproterenol hydrochloride injection is contraindicated in patients with: Tachycardia ( 4 ) Ventricular arrhythmias ( 4 ) Angina pectoris ( 4 )
Side Effects
- 6 ADVERSE REACTIONS The following adverse reactions have been associated with use of isoproterenol. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency reliably or to establish a causal relationship to drug exposure. Nervous system disorders: Nervousness, headache, dizziness, visual blurring Cardiovascular: Tachycardia, tachyarrhythmias, palpitations, angina, ventricular arrhythmias, Adams-Stokes attacks, pulmonary edema Respiratory: Dyspnea Other: Flushing of the skin, sweating, mild tremors, pallor,...
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, levothyroxinesodium, and certain antihistamines, notably...