| Name: |
DOBUTAMINE (DobutrexR) |
| Classification: |
sympathomimetic; inotropic agent
- Synthetic derivative of isoproterenol; decreases afterload
- Stimulates beta1 adrenergic receptors to increase myocardial contractility (inotrope) with varying degrees of chronotrope (increase in HR)
- Has some bet2 adrenergic properties that promotes mild vasodilation and reduction in systemic vascular resistance
- Alpha adrenergic receptors increase blood pressure at low dose
Used for short-term inotropic support for reduced cardiac output (inodilator properties)
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| Dose: |
Infusion:
2.5-20 mcg/kg/min (start at low dose and titrate to target cardiac index, venous oxygen saturation or other indicators of cardiac output)
Maximum dose of 40 mcg/kg/minute
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| Administration: |
IV Infusion
1000 mg/250 mL dextrose 5%, normal saline 0.9% or Ringer's Lactate (4 mg/mL = 4,000 mcg/mL)
- Protect from light
- May turn pink in solution without affecting potency
- Hypovolemia, acidosis and hypoxemia should be corrected concurrently with therapy
- Should be weaned off
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| Contraindications: |
- Hypersensitivity to dobutamine or components (contains a sulfite preservative) - a relative contraindication and would not usually apply to emergency situations
- Pheochromocytoma
- Idiopathic hypertrophic subaortic stenosis
Caution: Do not start if patient is hypotensive - correct hypotension before initiation. Increased hypotension at doses > 20 mcg/kg/min or in patients with sepsis/vasodilator shock)
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| Adverse Effects: |
CVS
- Hypotension, especially in patients with sepsis who need inotropic therapy (beta 2 vasodilation)
- Arrhythmias/ectope
- Tachycardia, palpitations
- Chest pain, angina (increased oxygen demand)
- Hypertension (usually at low dose)
OTHER
- Hyperglycemia
- Hypokalemia
- Headache
- Nausea and vomiting
- Mild leg cramps, paresthesia
- Dyspnea
- Local phlebitis
- Extravasation of drug may cause tissue necrosis (may be Rx with 5-15 mg phentolamine in NS - see phentolamine monograph)
Special Risk for Torsades de Pointes (TdP):
Dobutamine does not prolong the QT interval, BUT has a special risk of TdP because of its other actions; which includes epinephrine-like effects. It should be avoided in patients with Congenital Prolonged QT Syndrome (CLQTS). Physicians with expertise in the treatment of these arrhythmias may prescribe dobutamine to carefully selected patients with CLQTS.
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| Drug Interactions: |
- dobutamine + other sympathomimetics = increased risk of toxicity
- dobutamine + theophylline = increased risk of toxicity
- dobutamine + general anaesthetics = arrhythmias
- dobutamine + beta blockers = decreased inotropic effect
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| Monitoring Therapy: |
- IV site
- Continuous heart rate and ECG rhythm
- Blood pressure
- Central or mixed venous oxygen
- Lactate
- Hourly urine output
- Cardiac index if available
- Blood glucose
- Blood gases
- Electrolytes
- Urea, creatinine
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| Adult Critical Care Protocol: |
- May be administered by IV infusion by a nurse in Adult Critical Care.
- May be titrated by a nurse in Adult Critical Care.
- Central venous access device preferred; monitor peripheral site closely and document Infiltration and Phlebitis scale Q1H. Knowledge of the treatment for infiltration of vasoconstricting drugs is required.
- Patients requiring continuous infusions require the placement of an arterial line to monitor BP.
- Continuous infusions must be administered by infusion device and the pump library must be enabled.
- Should not be infused via the proximal injectate port (blue) of a pulmonary artery catheter. If this is the only available central venous line, it may be administered through the proximal injectate port but thermodilution cardiac output measurements must not be measured during infusion.
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