A guide to the rational use of dopamine, dobutamine and isoprenaline in patients who need inotropic support.

Which inotropic agent to use to the patient's greatest advantage is a common problem in hospital practice. Sympathetic nervous system physiology is outlined to explain the actions of dopamine, dobutamine and isoprenaline. The following suggestions are made: Where a low-dosage inotropic effect is required, dopamine should probably be used because of the unique benefit of increased renal blood flow. Where there are no tachyarrhythmias, dopamine should be the drug of choice. In dosages greater than 5 - 10 micrograms/kg/min, dopamine should be combined with nitroprusside. If further inotropic activity is required, the effect of dopamine can be increased with the concomitant use of isoprenaline. In the presence of tachyarrhythmias dobutamine may be of benefit.