dobutamine hydrochloride

Action

Stimulates beta₁-adrenergic receptors of heart, causing a positive inotropic effect that increases myocardial contractility and stroke volume. Also reduces peripheral vascular resistance, decreases ventricular filling pressure, and promotes atrioventricular conduction.

Availability

Injection: 12.5 mg/ml in 20-ml vials

Indications and dosages

➣ Short-term treatment of cardiac decompensation caused by depressed contractility (such as during refractory heart failure); adjunct in cardiac surgery

Adults: 2.5 to 10 mcg/kg/minute I.V. as a continuous infusion, adjusted to hemodynamic response

Dosage adjustment

• Elderly patients

Off-label uses

• Adjunct in myocardial infarction (MI) and septic shock

• Diagnosis of coronary artery disease (echocardiography stress test, ventriculography, computed tomography)

Contraindications

• Hypersensitivity to drug

• Idiopathic hypertrophic subaortic stenosis

Precautions

Use cautiously in:

• hypertension, MI, atrial fibrillation, hypovolemia

• pregnant or breastfeeding patients

• children.

Administration

• As needed, correct hypovolemia before starting therapy by giving volume expanders, as prescribed.

• Use infusion pump or microdrip I.V. infusion set.

• Dilute with dextrose 5% in water or normal saline solution to at least 50 ml of solution. Know that drug is incompatible with alkaline solutions, such as sodium bicarbonate injection.

Adverse reactions

CNS: headache

CV: hypertension, hypotension, tachycardia, premature ventricular contractions, angina, palpitations, nonspecific chest pain, phlebitis

GI: nausea, vomiting

Metabolic: hypokalemia

Respiratory: dyspnea, asthma attacks

Skin: extravasation with tissue necrosis

Other: hypersensitivity reactions including anaphylaxis

Interactions

Drug-drug. Beta-adrenergic blockers: increased alpha-adrenergic effects

Bretylium: potentiation of vasopressor activity

Cyclopropane, halothane: serious arrhythmias

Guanethidine: decreased hypotensive effects

Thyroid hormone: increased cardiovascular effects

Tricyclic antidepressants: potentiation of cardiovascular and vasopressor effects

Drug-herbs. Rue: increased inotropic potential

Patient monitoring

• Monitor ECG and blood pressure continuously during administration.

• Monitor cardiac output, pulmonary capillary wedge pressure, and central venous pressure.

• Monitor fluid intake and output and watch for signs and symptoms of worsening heart failure.

See Assess electrolyte levels. Stay especially alert for hypokalemia.

Patient teaching

• Instruct patient to report anginal pain, headache, leg cramps, and shortness of breath.

• Explain need for close observation and monitoring.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and herbs mentioned above.