Each mL contains: Dobutamine (as hydrochloride) 50 mg.
Pharmacology: Although dobutamine is usually considered to be a beta1 agonist, animal studies suggest that its ability to stimulate alpha1- and beta2-adrenergic receptors may be as great as its beta1-stimulant properties. It has been proposed that the inotropic action results from a combination of alpha-stimulant activity on myocardial alpha1 receptors, a property residing mainly in the (-)-enantiomer, with beta1 stimulation by the (+)-enantiomer; peripherally, alpha-mediated vasoconstriction would be opposed by the beta 2-agonist properties of the (+)-enantiomer, resulting in the net inotropic action with relatively little effect on blood pressure seen with the racemic mixture used clinically. Dobutamine has a thermogenic effect increasing oxygen delivery and utilization in healthy individuals. However, using it for this purpose in critically ill patients did not improve patient outcome and in some cases might have been harmful. Dobutamine is a sympathomimetic with direct effects on beta1-adrenergic receptors, giving it a prominent inotropic action on the heart. It also has some alpha- and beta2-agonist properties. Although it is structurally related to dopamine, it has no specific dopaminergic properties; however, like dopamine, the inotropic action of Dobutamine on the heart is associated with less cardiac-accelerating effect than that of isoprenaline.
Pharmacokinetics: Like adrenaline Dobutamine is inactive when given orally, and it is rapidly inactivated in the body by similar processes. It has a half-life of about 2 minutes. Conjugates of Dobutamine and its major metabolite 3-O-methyldobutamine are excreted primarily in urine, with small amounts eliminated in the faeces. The primary mechanism of clearance of Dobutamine appears to be distribution to other tissues, and not metabolism or elimination. It has a half-life of about 2 minutes and plasma concentrations of Dobutamine reach steady state about 10 to 12 minutes after the start of an infusion. Dobutamine is used mainly for the short-term treatment of heart failure and any pharmacokinetic changes in this condition have no clinical implications in dosage titration.
Dobutamine is used to increase the contractility of the heart in acute heart failure, as occurs in cardiogenic shock and myocardial infarction. It is also used in septic shock. Other circumstances in which its inotropic activity may be useful are during cardiac surgery and positive end-expiratory pressure ventilation.
It is given by intravenous infusion as a dilute solution (0.25 to 5 mg/mL), in glucose 5% or sodium chloride 0.9%. In the management of acute heart failure, Dobutamine is given at a usual rate of 2.5 to 10 micrograms/kg per minute. In the use as cardiac stress testing, a solution containing 1 mg/mL is given via an infusion pump in a dose of 5 micrograms/kg per minute for 8 minutes. The dose is then increased by increments of 5 micrograms/kg per minute up to a usual maximum of 20 micrograms/kg per minute, with each dose being infused for 8 minutes before the next increase; doses of up to 40 micrograms/kg per minute have sometimes been used.
Hypersensitivity reactions have been reported in patients receiving dobutamine infusions, possibly due to sodium sulfite in the formulation. Redness, swelling, itching, and a sensation of warmth developed around the infusion site in a patient receiving dobutamine; the reaction recurred when the infusion was repeated a week later. Eosinophilic reactions have also been reported, including hypersensitivity myocarditis and asthma.
Dobutamine has primarily inotropic effects and should be avoided or used only with great caution in patients with marked obstruction of cardiac ejection, such as idiopathic hypertrophic subaortic stenosis. It should also be used with caution in patients with acute myocardial infarction, and in cardiogenic shock complicated by severe hypotension. Hypovolaemia should be corrected before treatment.
Dobutamine has mainly beta1-agonist properties and its principal adverse effects include dose-related increases in heart rate and blood pressure, ectopic beats, angina or chest pain, and palpitations; dosage should be reduced or temporarily stopped if they occur. Ventricular tachycardia may occur rarely; cardiac rupture has been reported rarely during dobutamine stress testing.
Most interactions with Dobutamine are due to its direct beta1 agonist effects on the heart, but use with beta blockers may allow its alpha-and beta2-agonist effects to become apparent.
Store at temperatures not exceeding 30°C. Diluted Dobutel infusion solution remains effective for 12 hrs at room temperature and 24 hrs in refrigerator. Unused concentrate must be discarded.
C01CA07 - dobutamine ; Belongs to the class of adrenergic and dopaminergic cardiac stimulants excluding glycosides. Used in the treatment of hypotension.
Soln for inj (vial) 50 mg/mL x 5 mL x 1's.