Dobutamine

 Action Stimulates beta1-receptors in heart, causing more complete and forceful contractions (inotropy) without significantly increasing heart rate or BP.

 Indications Treatment of cardiac decompensation caused by organic heart disease or cardiac surgical procedures. Unlabeled use(s): Congenital heart disease in children undergoing diagnostic cardiac catheterization.

 Contraindications Idiopathic hypertrophic subaortic stenosis.

 Route/Dosage

ADULTS: IV infusion 2.5 to 10 mcg/kg/min; titrate to desired response; increase in heart rate > 10% may develop in rate > 20 mcg/kg/min; rates up to 40 mcg/kg/min are rarely used. Duration of therapy up to 72 hr without decrease in clinical effectiveness may be used.

 Interactions

Beta-blockers: May antagonize beta receptor-stimulating activity of dobutamine. Furazolidone, methyldopa, rauwolfia alkaloids: Hypertension may result. Guanethidine: May increase pressor response. Halogenated hydrocarbon anesthetics: May increase risk of arrhythmias by sensitizing cardiac tissue to sympathomimetic agents. Tricyclic antidepressants: May potentiate effect of dobutamine; use combination with caution. Incompatibilities: Chemically incompatible with sodium bicarbonate or other alkaline solutions.

 Lab Test Interferences None well documented.

 Adverse Reactions

CV: Increased systolic BP; increased heart rate; chest pain; increased number of premature ventricular beats. CNS: Headache; tingling sensations; paresthesia. GI: Nausea; vomiting. RESP: Dyspnea. OTHER: Phlebitis; local inflammation after infiltration; leg cramps.

 Precautions

Pregnancy: Safety not established. Lactation: Undetermined. Children: Safety and efficacy not established. Special risk patients: Use with extreme caution after myocardial ischemia. Avoid use in uncorrected hypovolemic states unless used as temporary emergency measure to maintain coronary and cerebral flow. Cardiovascular effects: May greatly increase BP and heart rate, especially with preexisting hypertension. Dose reduction may reverse effects. May precipitate or exacerbate ventricular ectopic activity. Hypokalemia: Mild hypokalemia may occur. Sulfite sensitivity: Use caution in sulfite-sensitive individuals; some preparations contain sodium bisulfite.

 Administration/Storage

• Administer by IV infusion only. Use electronic infusion device to monitor infusion rate.
• Reconstitution/dilution is done in two stages.
• First, more concentrated solution can be kept under refrigeration for 48 hr or at room temperature for 6 hr.
• Before administration, solution is further diluted to typical concentration of 0.25 to 1 mg/ml (250 to 1000 mcg/ml). Final concentration should not exceed 5 mg/ml. This solution should be used within 24 hr.
• Solution may have pink color, because of slight oxidation, but this effect does not indicate loss of potency.
• Do not freeze solution because crystallization may occur.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies.
• Monitor vital signs, ECG, cardiac output, pulmonary capillary wedge pressure, central venous pressure and urinary output carefully throughout infusion.
• Monitor potassium levels to detect possible hypokalemia.
• Monitor patency and placement of IV catheter to reduce risk of extravasation and phlebitis.
• If patient has diabetes, monitor blood glucose level. Report significant increase to physician.

 Patient/Family Education

• Instruct patient to report these symptoms to physician: pain or discomfort at IV site, any anginal pain.