The management of heart failure and the scope for new therapies: what role for xamoterol?

1. Current therapy of heart failure leaves much to be desired. Not all patients respond, and many agents lose their effects with time. 2. Newer agents may be effective but toxic, and some which have a beneficial action when given intravenously have proved disappointing when used orally. 3. The value of digoxin in patients in sinus rhythm is open to debate, and diuretics, although useful acutely in reducing fluid overload, do not appear to improve prognosis. 4. Vasodilators increase effort capacity and reduce symptoms, possibly conferring some long-term benefit, and angiotensin converting enzyme (ACE) inhibitors improve symptoms and decrease mortality in a wide range of patients. 5. Positive inotropes may be effective in the short term, but they increase myocardial oxygen demand and show tachyphylaxis with no prognostic benefit. 6. Xamoterol (Corwin, Carwin, Corwil, Xamtol, ICI 118,587) is a partial sympathetic agonist with approximately 50% of the activity of a pure agonist, which provides inotropic support at rest, and protection against excess sympathetic activity on exercise. 7. It is compatible with other therapies and has shown no serious toxicity. 8. It should be considered at present as an adjunct to diuretic and/or ACE inhibitor therapy, although it may be useful alone; its role will become clearer as its effects on mortality are established.