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Action/Kinetics:
Produces vasoconstriction (increase in BP) by stimulating alpha-adrenergic receptors. Also causes a moderate increase in contraction of heart by stimulating beta-1 receptors. Minimal hyperglycemic effect.
Onset: immediate;
duration: 1-2 min. Metabolized in liver and other tissues by the enzymes MAO and catechol-O-methyltransferase; however, the pharmacologic activity is terminated by uptake and metabolism in sympathetic nerve endings. Metabolites excreted in urine.
Uses:
Hypotensive states caused by trauma, septicemia, blood transfusions, drug reactions, spinal anesthesia, poliomyelitis, central vasomotor depression, and MIs. Adjunct to treatment of cardiac arrest and profound hypotension.
Additional Contraindications:
Hypotension due to blood volume deficiency (except in emergencies), mesenteric or peripheral vascular thrombosis, in halothane or cyclopropane anesthesia (due to possibilities of fatal arrhythmias). Pregnancy (may cause fetal anoxia or hypoxia).
Special Concerns:
Use with caution in clients taking MAO inhibitors or tricyclic antidepressants.
Additional Side Effects:
Bradycardia that can be abolished by atropine.
How Supplied:
Injection: 1 mg/mL
Dosage
?IV Infusion Only
Effect on BP determines dosage, initial: 8-12 mcg/min or 2-3 mL of a 4-mcg/mL solution/min;
maintenance, 2-4 mcg/min with the dose determined by client response.
