We performed a double-blind, placebo-controlled study to determine whether oral enoximone would aid weaning dobutamine-dependent patients. Twenty-four patients 64 +/- 10 years, with an echocardiographic ejection fraction of 0.20 +/- 0.06, and receiving maximal therapy were studied. After failure of dobutamine weaning, a dobutamine infusion was set up at 10 micrograms.kg-1.min-1 for 48 h. Oral enoximone (100 mg t.i.d.) or placebo was added from D0 for the next 28 days, while the dobutamine dosage was progressively decreased after D4 and eventually stopped at D7. The patients were then followed-up for 21 days (i.e. until enoximone administration had continued for 28 days). In the placebo group, two patients suffered a relapse of congestive heart failure (CHF) before D4, six patients withdrew during dobutamine tapering (five with a relapse of CHF and one with septic shock) and two during follow-up (one with a relapse of CHF and one with sustained ventricular tachycardia). In the enoximone group, three patients withdrew during dobutamine tapering (two with a relapse of CHF, one with a cutaneous rash). Four patients on placebo and nine receiving enoximone could be weaned from dobutamine, P < 0.05. Echocardiographic LV ejection fraction significantly increased and Doppler-derived indexes of systolic function tended to increase when enoximone but not placebo was associated with dobutamine. Oral enoximone might be helpful in weaning patients with end-stage congestive heart failure from i.v. dobutamine.