Clinical studies indicate that dopamine at low and intermediate therapeutic doses usually increases systolic and pulse pressure with either no effect or a slight increase in diastolic pressure, and total peripheral resistance is usually unchanged. Blood flow to peripheral vascular beds may decrease while mesenteric flow increases. Dopamine has also been reported to dilate the renal vasculature presumptively by activation of a dopaminergic receptor. This action is accompanied by increases in glomerular filtration rate, renal blood flow, and sodium excretion. An increase in urinary output produced by dopamine is usually not associated with a decrease in osmolality of the urine.
Dopamine is a rapidly acting compound.
Cardiovascular effects are usually evident within 10 minutes and renal response usually occurs within 30 minutes. The half-life of dopamine is approximately 1.75 minutes. For the correction of hemodynamic imbalances present in the shock syndrome due to myocardial infarction, trauma, endotoxic septicemia, open heart surgery, renal failure and chronic cardiac decompensation as in congestive failure. Where appropriate, restoration of blood volume with a suitable plasma expander or whole blood should be instituted or completed prior to dopamine administration. Patients most likely to respond adequately to dopamine are those in whom physiological parameters, such as urine flow, myocardial function, and, blood pressure, have not undergone profound deterioration.