Dobucard

Dobutamine hydrochloride.

Each mL contains Dobutamine (as Hydrochloride) 25 mg.

Pharmacology: Dobutamine is a sympathomimetic with direct effects on beta₁-adrenergic receptors, which confer upon it a prominent inotropic action on the heart. It also has some alpha- and beta₂-agonist properties.
Dobutamine does not have the specific dopaminergic properties of dopamine which include renal mesenteric vasodilation. However, the inotropic action of Dobutamine on the heart is associated with less cardiac-accelerating effect than that of isoprenaline.
Mechanism of Action: The ability of Dobutamine to stimulate alpha₁- and beta₂-adrenergic receptors appears to be as great as its beta₁-stimulant properties, and 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 beta₂-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.
Pharmacokinetics: Dobutamine is inactive when given by mouth, 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-Omethyldobutamine are excreted primarily in urine, with small amounts eliminated in the feces. The primary mechanism of clearance of Dobutamine appears to be distribution to other tissues. 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. It 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.

Dobutamine is given as the hydrochloride but doses are expressed in terms of the base. It is administered by intravenous infusion as a dilute solution (0.25 to 5 mg per mL), in glucose 5% or sodium chloride 0.9%; other fluids may also be suitable.
In the management of acute heart failure, Dobutamine is given at a usual rate of 2.5 to 10 mcg per kg body-weight per minute, according to the patient’s heart rate, blood pressure, cardiac output, and urine output. A range of 0.5 up to 40 mcg per kg per minute has occasionally been required. It has been recommended that treatment with Dobutamine should be discontinued gradually.
Dobutamine is also employed as an alternative to exercise in cardiac stress testing. A solution containing 1 mg per mL is employed for this purpose, administered via an infusion pump. A dose of 5 mcg per kg per minute is infused for 8 minutes; the dose is then increased by increments of 5 mcg per kg per minute up to a usual maximum of 20 mcg per kg per minute, with each dose being infused for 8 minutes before the next incremental increase; higher doses of up to 40 mcg per kg per minute have sometimes been employed.
Or prescribed by a physician.

The symptoms of toxicity may include anorexia, nausea, vomiting, tremor, anxiety, palpitations, headache, shortness of breath and anginal and nonspecific chest pain. The positive inotropic and chronotropic effects of Dobutamine on the myocardium may cause hypertension, tachyarrhythmias, myocardial ischemia and ventricular fibrillation. Hypotension may result from vasodilation.
The initial actions to be taken in a Dobutamine HCl overdose are discontinuing administration, establishing an airway and ensuring oxygenation and ventilation. Resuscitative measures should be initiated promptly. Severe ventricular arrhythmias may be successfully treated with propranolol or lidocaine. Hypertension usually responds to a reduction in dose or discontinuation of therapy.

Dobutamine HCl should be avoided or used only with great caution in patients with marked obstruction of cardiac ejection, such as idiopathic hypertrophic subaortic stenosis.

This preparation contains sodium metabisulfite, which may cause allergic-type reactions including anaphylactic symptoms and life threatening or less severe asthmatic episodes in certain susceptible people.

Dobutamine HCl should be used with caution in patients with acute myocardial infarction, and in cardiogenic shock complicated by severe hypotension. Hypovolemia should be corrected before treatment using Dobutamine.
Dobutamine should also be used with great caution in patients who may be particularly susceptible to its cardiovascular actions, notably those with pre-existing arrhythmias or tachycardia, Prinzmetal's angina, thromboembolic disorders, or a history of ischemic heart disease. Extreme care is also needed in conditions which predispose a patient to adverse effects on the heart, such as hyperthyroidism; elevated thyroid hormone concentrations may also enhance receptor sensitivity. Special care is also needed in the elderly who may have pre-existing coronary or cerebrovascular disease.
Interference with diagnostic tests is caused by Dobutamine. Contamination of blood samples with Dobutamine has been reported to produce falsely decreased creatinine values in an enzymatic test.

The principal adverse effects of Dobutamine are 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. Other adverse effects that have occurred occasionally include hypotension, paraesthesias, headache, nausea and vomiting, and leg cramps. Side effects such as anxiety, dyspnoea, hyperglycemia, restlessness, palpitations, tachycardia (sometimes with anginal pain), tremors, sweating, hypersalivation, weakness, dizziness, headache and coldness of extremities may occur even with low doses. Overdosage may cause cardiac arrhythmias and a sharp rise in blood pressure (sometimes leading to cerebral hemorrhage and pulmonary edema); these effects may occur at normal dosage in susceptible subjects.
Since Dobutamine does not readily cross the blood-brain barrier, its central effects, which encompass anxiety, fear, restlessness, insomnia, confusion, irritability, and psychotic states, may be largely a somatic Dobutamine Hydrochloride response to its peripheral effects. Anorexia, nausea and vomiting, may occur similarly. In relation to some other adverse effects, difficulty in micturition with urinary retention is a characteristic of alpha₁-receptor stimulation whereas muscle tremor and hypokalemia are characteristics of beta₂-receptor stimulation.
The potent alpha-adrenergic effects of adrenaline may lead to gangrene following the vasoconstriction that is induced by infiltration of adrenaline-containing local anesthetic solutions into digits. Extravasation of parenterally administered adrenaline similarly causes intense vasoconstriction, resulting in tissue necrosis and sloughing.

Dobutamine should be used with extreme caution during anesthesia with cyclopropane, halothane and other volatile anesthetics.

Store at temperatures not exceeding 30°C. Do not freeze. Protect from light.

Cardiac Drugs

C01CA07 - dobutamine ; Belongs to the class of adrenergic and dopaminergic cardiac stimulants excluding glycosides. Used in the treatment of hypotension.

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