Dobutel

Dobutamine hydrochloride.

Each mL contains Dobutamine HCl equivalent to 50 mg Dobutamine.

Pharmacology: Dobutamine is a sympathomimetic amine which has a strong stimulating effect on cardiac β₁ receptors and a weak effect on β₂- and α₁-receptors. The inotropic effect of dobutamine results from direct stimulation of cardiac β₁-receptors. It increases myocardial contractility, seldom induces a marked increase in heart rate (although tachycardia is occasionally observed), or arrhythmogenic or peripheral vascular effects.
Dobutamine exerts a dose-related, positive-inotropic effect at dose levels which do not significantly increase the heart rate. The risk of tachycardia and cardiac arrhythmia provoked by Dobutamine has proved to be relatively small. In patients with depressed cardiac output, stroke volume is also usually increased and systemic vascular resistance decreases.
Dobutamine is suitable for short-term inotropic support of the failing heart in patient with insufficient cardiac output and high left ventricular filling pressure but only slightly or moderately decreased blood pressure. Dobutamine is not suitable for monotherapy in severe hypotension or shock requiring vasopressor effect. In these patients, the result is probably obtained by using Dobutamine and dopamine concomitantly.
Pharmacokinetics: The onset of action of Dobutamine is within 2 minutes after instituting IV infusion. Peak plasma concentrations of the drug and peak effect occur within 10 minutes after initiation of IV infusion. The plasma half-life of Dobutamine is about 2 minutes.

Inotropic support of the myocardium in the short term treatment of patients with cardiac decompensation due to depressed contractibility resulting either from organic heart disease or from cardiac surgical procedures.

The rate of infusion needed to increase cardiac output usually 2.5-10 μg/Kg/min. On rare occasions, infusion rates up to 40 μg/Kg/min have been required to obtain the desired effect. The dosage should be adjusted individually, according to the patient's heart rate and rhythm, blood pressure and diuresis. Partial tolerance may develop if infusion time exceeds 72 hrs and such cases may call for an increase in dosage.
Infusion concentrate 50 mg/mL (250 mg/5mL): The dosage is determined as follows: See table.

Click on icon to see table/diagram/image

The infusion rate values corresponding to each dosage are multiplied by the patient's weight as kilograms. This gives the infusion rate as mL/min.
Dilution: For infusion, the infusion concentrate is diluted in physiological sodium chloride (0.9% sodium chloride injection), 5% glucose injection, 5% glucose and 0.9% sodium chloride injection, 20% mannitol injection, Ringer's lactate injection, or Ringer's lactate and 5% glucose injection. The prepared infusion solution should be used within 30 hours. (See Storage.)
Note: Do not add Dobutel Injection to Sodium bicarbonate injection or to any other strongly alkaline solution. Because of potential physical incompatibilities, it is recommended that Dobutel injection not be mixed with other drugs in the same solution. Dobutel injection should not be used in conjunction with other agents or diluents containing both sodium bisulfite and ethanol.

At overdosage, which manifests itself as excessive blood pressure changes or tachycardia, the infusion rate must be reduced or therapy discontinued until the patient is in balance.

Obstructive cardiomyopathy. Known hypersensitivity to dobutamine. Patients with idiopathic hypertrophic subaortic stenosis.

During treatment with Dobutel, ECG and blood pressure should be monitored continuously. In addition, cardiac filling pressure and output should be monitored whenever possible. Hypovolemia should always be corrected before instituting Dobutamine therapy. Dobutamine, like any catecholamine, may provoke chest pain in patients with coronary heart disease. Therefore, the dosage should be carefully considered. Care should also be taken after acute myocardial infarction, excessive inotropism and tachycardia should be avoided as these may increase myocardial oxygen consumption and consequently, infarct size.
Dobutamine usually causes a slight increase in systolic blood pressure (10-20 mmHg) and heart rate (5-10 beats/min). Unusually high blood pressure increases have been reported especially in patients with arterial hypertension. Sometimes, excessive tachycardia may occur. Discontinuation of infusion or reduction of infusion rate usually normalizes the situation rapidly.
Dobutamine increases atrioventricular conduction. Therefore, care should be taken when determining the dosage for patients with atrial fibrillation. These patients should preferably be digitalized before dobutamine therapy is instituted. Dobutamine may provoke ventricular ectopic activity.
Hypersensitivity: Reactions suggestive of hypersensitivity associated with administration of Dobutel injection, including skin rash, fever, eosinophilia and bronchospasm, have been reported occasionally.
Dobutel injection contains sodium bisulfite, a sulfite that may cause allergic-type reactions, including anaphylactic symptoms and life-threatening or less severe asthmatic episodes, in certain susceptible people. The overall prevalence of sulfite sensitivity in the general population is unknown and probably low. Sulfite sensitivity is seen more frequently in asthmatic than in non-asthmatic people.
Use in Pregnancy: As dobutamine injection has not been administered to pregnant women, the physician should, in each case, weigh the benefits against the potential risks.
Use in Lactation: It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when dobutamine is administered to a nursing woman. If the mother requires dobutamine treatment, breastfeeding should be discontinued for the duration of the treatment.
Use in Children: Special attention should be paid to the monitoring of immediate haemodynamic effects, as these may differ both in quality and strength from those occurring in adults. Heart rate and blood pressure may increase more commonly and strongly in children. In contrast to adults, an increase in pulmonary wedge pressure may occur especially in infants under 1 year of age.

Use in pregnancy: As dobutamine injection has not been administered to pregnant women, the physician should, in each case, weigh the benefits against the potential risks.
Use in lactation: It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when dobutamine is administered to a nursing woman. If the mother requires dobutamine treatment, breastfeeding should be discontinued for the duration of the treatment.

These are essentially dose-dependent and can therefore be controlled by reducing the infusion rate. Since dobutamine is almost completely eliminated within 10 min, the side effects will disappear promptly with a reduction of dosage or discontinuation of infusion.
Nausea, headache, palpitation, dyspnea and chest pain have been reported as the most common side effects.
Anginal pain, shortness of breath, skin rash, eosinophilia and bronchospasm.
Increased heart rate, blood pressure and ventricular ectopic activity.
Hypotension: Precipitous decreases in blood pressure have occasionally been described in association with dobutamine therapy.
Reactions at sites of i.v. infusion. Phlebitis occasionally been reported.

In clinical studies, no evidence has been found of drug interactions between dobutamine and other drugs. Preliminary studies indicate that the concomitant administration of Dobutamine and nitroprusside increases cardiac output and usually reduces pulmonary capillary wedge pressure more than either of these drugs alone. Animal studies indicate that dobutamine may prove ineffective in patients recently treated with β-adrenoreceptor-blocking drugs. In such cases, peripheral vascular resistance may increase.

Incompatibilities: Dobutel should not be mixed with alkaline solutions.

Store at temperature below 30°C and protect from light.
Diluted Dobutel infusion solution remains effective for 30 hours at temperature below 30°C and in a refrigerator (2-8°C). Unused concentrate must be discarded.
Shelf Life: 4 years.

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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