A DOUBLE-BLIND, CROSS-OVER COMPARISON OF THE EFFECTS OF A LOOP DIURETIC AND A DOPAMINE-RECEPTOR AGONIST AS FIRST LINE THERAPY IN PATIENTS WITH MILD CONGESTIVE-HEART-FAILURE

We compared the effects of the orally active dopamine agonist ibopamin e with the loop diuretic frusemide as first-line therapy in patients w ith mild congestive heart failure. Fourteen patients with New York Hea rt Association class II congestive heart failure were enrolled in a do uble-blind, cross-over study. After baseline measurements of clinical and symptomatic status, modified Bruce exercise time, high-level exerc ise time, corridor walk time, regional blood flow, pedometer scores, 2 4 h urine volume and sodium excretion and neurohumoural factors, patie nts were randomly allocated to receive either frusemide 40 mg o.d. or ibopamine 100 mg t.d.s. for 8 weeks. Assessments were performed at 2 w eekly intervals. After 8 weeks, patients crossed over into the alterna te treatment arm for a further 8 weeks, with further assessments perfo rmed every 2 weeks. There were four exacerbations of heart failure dur ing ibopamine treatment and none during frusemide treatment. After 8 w eeks of treatment, modified Bruce exercise time was 901 +/- 73 s with frusemide and 646 +/- 134 s with ibopamine (P<0.05). Twenty-four hour urinary sodium excretion at weeks 2 and 4 (P<0.05), and 24 h urinary v olume at week 2 (P=0.0001) were lower during ibopamine treatment. At w eek 8, supine (P=0.076) and erect renin (P=0.05 were lower with ibopam ine treatment. In conclusion, ibopamine is ineffective as first line t herapy for congestive heart failure, probably because of a lesser diur etic potency than frusemide.