The clinical use of inotropes in cardiac failure: dopamine, dobutamine, prenalterol and pirbuterol.

The impaired cardiac performance in patients with congestive cardiac failure may be improved by the introduction of inotropic therapy. Dopamine and dobutamine are both potent cardiac stimulants although their haemodynamic profile is different. Dobutamine would appear to be the more appropriate choice in cardiac failure because of the additional benefit of preload reduction although in the context of severe hypotension dopamine would be preferred. The need for intravenous administration, however, limits their clinical application. In acute studies, the oral agents prenalterol and pirbuterol, are effective in improving myocardial function; pirbuterol mainly due to peripheral vasodilatation and afterload reduction. There are few chronic studies but confirmation of sustained haemodynamic improvement is lacking. This could be due, either to the inexorable deterioration in cardiac function or to a reduction in the beta receptor population available for catecholamine stimulation.