Dobutamine

SOURCE: UK SPC (eMC) for Dobutamine 12.5 mg/ml concentrate for solution for infusion, §4.2 (https://www.medicines.org.uk/emc/product/100017/smpc). The SPC writes the unit as micrograms/kg/min (ug/kg/min) - NOT mg/kg. WORKED INFUSION RATES from the SPC: one ampoule (250 mg in 20 ml) diluted to 500 ml (final concentration 0.5 mg/ml) gives, at 2.5/5/10 micrograms/kg/min respectively, 15/30/60 ml/h for a 50 kg patient, 21/42/84 ml/h for 70 kg and 27/54/108 ml/h for 90 kg; if the concentration is doubled (500 mg in 500 ml, or 250 mg in 250 ml), halve the infusion rates. By syringe pump, one ampoule diluted to 50 ml (final concentration 5 mg/ml) gives 1.5/3.0/6.0 ml/h at 50 kg, 2.1/4.2/8.4 ml/h at 70 kg and 2.7/5.4/10.8 ml/h at 90 kg for 2.5/5/10 micrograms/kg/min. MONITORING: heart rate, heart rhythm, blood pressure, diuresis and infusion rate should be closely monitored; cardiac output, CVP and pulmonary capillary pressure if possible. Duration should be as short as clinically possible; if given continuously for more than 72 hours, tolerance (tachyphylaxis) may occur, requiring a dose increase. Hypovolaemia should be corrected before administering dobutamine. Incompatible with bicarbonate and other strong alkaline solutions. DOBUTAMINE STRESS ECHOCARDIOGRAPHY (adults only, separate indication with its own contraindications): the most frequently applied scheme starts at 5 micrograms/kg/min, increased every 3 minutes to 10, 20, 30, 40 micrograms/kg/min until a diagnostic endpoint is reached; if no endpoint is reached, atropine sulfate 0.5 to 2 mg may be given in divided doses of 0.25-0.5 mg at 1-minute intervals to increase heart rate, or alternatively the dobutamine infusion rate may be increased to 50 micrograms/kg/min - to be undertaken only by a physician experienced in cardiology stress testing, with continuous echocardiographic/ECG/BP monitoring and resuscitation facilities. §4.5 was not present in the fetched bundle, so no interaction list is given.

SPC §4.2: for all paediatric age groups (neonates to 18 years) an INITIAL dose of 5 micrograms/kg/minute, adjusted according to clinical response to 2-20 micrograms/kg/minute, is recommended (unit is micrograms/kg/MINUTE - not mg/kg). Occasionally a dose as low as 0.5-1.0 micrograms/kg/minute will produce a response. The minimum effective dose in children is believed to be higher than in adults, while the maximum tolerated dose is believed to be lower - use caution with high doses. Response varies greatly between paediatric patients, so the dose cannot be determined a priori and must be titrated. Reducing or stopping the infusion is usually all that is required for rapid reversal of undesirable effects. NEONATAL INTENSIVE CARE (SPC method of administration): dilute 30 mg/kg body weight to a final volume of 50 ml of infusion fluid - an infusion rate of 0.5 ml/hour then provides a dose of 5 micrograms/kg/minute. Increments in heart rate and blood pressure appear more frequent and intense in children; pulmonary wedge pressure may not fall as it does in adults and may rise, especially in infants under one year. Dobutamine stress echocardiography is for the adult population only. Verify against a children's formulary.