COMBINED ALPHA-BETA BLOCKADE (DOXAZOSIN PLUS METOPROLOL) COMPARED WITH BETA-BLOCKADE ALONE IN CHRONIC CONGESTIVE-HEART-FAILURE

There has been growing evidence for the benefits of beta blockers, but alpha blockers have not shown sustained benefits in chronic congestiv e heart failure (CHF). Thirty patients with moderate to severe CHF (Ne w York Heart Association class II to IV) were sequentially assigned to receive metoprolol 6.25 mg with the alpha-1 antagonist doxazosin 4 mg /day or metoprolol alone. The dose of metoprolol was gradually increas ed to a target dose of 50 mg orally twice daily, Hemodynamic measureme nts were obtained before drug therapy, 2 hours after the first dose of combined alpha-beta therapy or metoprolol alone, and after 3 months o f continuous treatment. Nuclear ejection fraction, plasma norepinephri ne, and submaximal and maximal exercise capacity were also measured be fore and after chronic therapy. With initial combined drug administrat ion, mean arterial pressure, left ventricular filling pressure, and sy stemic vascular resistance decreased significantly compared with resul ts after metoprolol alone. However, after 3 months of continuous thera py, both treatment groups showed similar and significant reductions in systemic vascular resistance and heart rate, with significant increas es in cardiac index, stroke volume index, stroke work index, ejection fraction, and exercise capacity. Furthermore, the next dose of chronic combined medication no longer showed vasodilating effects. Chronic th erapy with fixed-dose doxazosin and increasing doses of metoprolol pro duced identical effects as those seen in patients receiving metoprolol alone.