Long-term studies with xamoterol in heart failure.

1. Xamoterol (Corwin, Carwin, Corwil, Xamtol, ICI 118,587) is a beta 1-adrenoceptor partial agonist which, unlike full beta-adrenoceptor agonists, does not down-regulate beta-adrenoceptors in the rat ventricle during chronic administration. 2. Improvements in myocardial performance have been demonstrated following acute administration of xamoterol to patients with mild or moderate heart failure, and these are sustained during at least 1 year of continued treatment. 3. Exercise duration is increased by xamoterol in patients with left ventricular dysfunction and benefit is still apparent after at least 1 year of therapy. 4. Despite sustained cardiac stimulation, xamoterol does not appear to affect adversely mortality in patients with mild or moderate heart failure. 5. Few adverse events directly attributable to xamoterol were reported during 3 month efficacy studies in more than 600 patients, and the laboratory safety profile over 1 year of treatment is good. 6. Xamoterol is a promising, well-tolerated addition to established therapies for chronic mild or moderate heart failure.