DOBUTAMINE HYDROCHLORIDE DOBUTREX)

DOBUTAMINE HYDROCHLORIDE DOBUTREX)

CLASSIFICATION

� Inotropic agent

MODE OF ACTION

� Dobutamine is an inotropic agent whose primary activity is the stimulation of beta receptors of the heart while producing comparatively mild chronotropic, hypertensive, arrhythmogenic and vasodialative effects.

� Causes an increase in cardiac output (C.O) usually not associated with a marked increase in heart rate, while the stroke volume is usually increased.

� Systemic vascular resistance is usually decreased due to stimulation of beta 2 receptors which contributes to the increased C.O.

 � Onset of action 1 - 2 minutes however as much as 10 minutes may be required to obtain the peak effect at a particular infusion rate.

� Half life is 2 minutes.

INDICATIONS

� Severe cardiac failure secondary to AMI or cardiomyopathy.

� Cardiogenic shock.

 � Septic shock.

� Congestive cardiac failure.

� Acute pulmonary oedema

CONTRA INDICATIONS

� Idiopathic hypertrophic subaortic stenosis

PRECAUTIONS

� Correct hypovolaemia

� Give cautiously in the presence of tachyarrhythmias

 � Digoxin should be given to patients with atrial fibrillation with rapid ventricular response prior to insituiting Dobutamine as Dobutamine facilitates atrioventricular conduction.

ADVERSE REACTIONS

� Heart rate of 5 - 15 BPM

� Blood pressure of 10 - 20 mmHg systolic

 � Ventricular ectopics.

 � Uncommon side effects include nausea, headache, angina, palpitations and dyspnoea.

 � May lower serum k

PRESENTATION

250 mg in 20 ml ampoule.

DOSAGE AND ADMINISTRATION

� Dilute 250 mg in 100 ml of Dextrose 5 % in a burette.

 � Solution = 2500 mcg/ml divided by 60 = 41 mcg/ml/min

� Dose range is 125 - 3000 mcg /min

RECOMMENDED DOSE RANGE

� 2.5 - 10 mcg/kg/min. May go up to 40 mcg/kg/min.

� Divide weight into mg/min to mcg/kg/min

NURSING CONSIDERATIONS

� Ideally monitor BP continuously. PA catheter often desirable.

 � Patient must be on cardiac monitor.

� ECG, BP, and hourly urine measures must be continuously monitored while PAWP and C.O should be monitored wherever possible.

� Dobutamine is chemically stable for 24 /24 and should be changed every 24/24.

� Dobutamine is titrated according to patient response as determined by HR, presence of ectopic bears, BP, urine output, CVP, PAWP and C.O. Titrated usually 1 - 2 mcg/kg/min increments until appropriate response is achieved.

� Dobutamine can be administered by a peripheral line.

� Dobutamine must always be administered via a volumetric infusion pump.

 � NB; long term low dose dobutamine infusions may be administered on general wards after the patient has been stable on the dose for a few days. These patients must remain on telemetry until the infusionis completed.