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.
