Abstract
Dobutamine 300 mg was administered orally to both healthy volunteers and to patients with circulatory failure. After the 300 mg dose of dobutamine, subjects were found to have a higher concentration of the drug in their plasma than the effective levels of 37.5 (SD 2.9) ng/ml (n = 5) normally seen during intravenous infusion of the clinically effective (5 μg/kg/min) dose. This increased concentration waned within 90 minutes.
A clinical effect of dobutamine on the circulation was observed in both the healthy volunteers and the patients. An increase in the cardiac index of the patients continued longer than 90 minutes. An unidentified substance was noticed on chromatography measuring plasma dobutamine concentrations, which may have contributed to the increased cardiac index, although its chemical formula could not be determined. The results suggest that the oral administration of dobutamine may be expected to have a long-lasting and significant therapeutic effect on patients with chronic circulatory failure.