OBJECTIVE To assess safety and efficacy of ibopamine, 200 mg TID, added to conventional treatment of congestive heart failure. METHODS A prospective, longterm, open study over two years (1986-88). A multicenter trial. METHODS Outpatients of Departments of Internal Medicine of S. Francisco Xavier Hospital and Sta. Maria Hospital, and Departments of Cardiology of Sta. Cruz Hospital and Hospital Militar Principal, Lisbon. METHODS 63 patients, 49 males from 34 to 80 years (m = 55.6 +/- 11.36) and 14 females from 41 to 80 years (m = 63 +/- 10.2), with congestive heart failure, NYHA class II in 52 patients (82.5%) and NYHA class III in 11 patients (17.5%) with a mean disease duration of 47.9 months entered into the study. Digoxin, diuretics, nitrates and antiarrhythmic drugs were allowed as concomitant therapy. Patients carried out clinical examination, ECG and laboratory tests monthly and X-Ray at the beginning and at the end of each year of the study. RESULTS 42 patients completed one year of treatment and 20/42 continued for an additional year, 17 patients completed this second year of follow-up. From the 42 patients who completed the first year period, the NYHA class changed from II to I in 17/38 from II to III in 2/38 patients from III to II in 3/4 patients, and from III to IV in one patient. Twenty patients dropped during the first year of treatment. Six for non-compliance (less than 80% of the treatment). Two were submitted to cardiac valve surgery. Seven had cardiovascular clinical events: one ventricular tachycardia, one atrial fibrillation, one pulmonary edema, one patient had no therapeutic effect, two patients had anxiety and fatigue and one patient died suddenly. One diabetic patient had uncontrolled hyperglycemia. One patient had gastric ulcer. Two had nausea and vomiting. Dysrhythmia and nausea and vomiting were the only clinical events, considered, respectively, possibly related and related, to ibopamine. During the second year of treatment 9/11 patients were stabilized in NYHA class I and 6/9 in NYHA class II, one patient changed from class II to class I, and one patient changed from class I to class II of the NYHA. Three patients did not complete the second year of treatment; one due to abnormal creatininemia; one for probable pulmonary embolism with CHF worsening; the third died suddenly. None of these events was considered related to ibopamine. Heart rate, arterial pressure, laboratory values and cardiothoracic index did not vary over the two years of the study. CONCLUSIONS This has been the first study with data from patients treated with 200 mg TID of ibopamine during two years. Ibopamine has been shown to be a safe and useful drug added to conventional treatment of cardiac heart failure. Clinical events were few and well controlled after ibopamine interruption.