Metoclopramide kinetics were examined in 24 adult patients with diminished renal function and in eight healthy subjects with normal renal function. Creatinine clearance correlated with metoclopramide plasma clearance, renal clearance, nonrenal clearance, and elimination t1/2. Regardless of renal function, renal clearance accounted for less than or equal to 21% of total plasma clearance. Nonrenal clearance was reduced in patients and accounted for most of the reduction in plasma clearance. The comparatively small plasma clearances in patients imply that maintenance doses should be reduced accordingly to avoid drug cumulation. Metoclopramide clearance by hemodialysis was also assessed in four patients. Metoclopramide losses from hemodialysis were relatively small compared to estimates of total body metoclopramide stores. Compensatory dosage increases are probably unnecessary for most patients. These data also suggest that hemodialysis is not likely to be effective in metoclopramide overdose.

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The renal effects of low-dose dopamine (LDD) therapy in hyperdynamic thermally injured peuents are unknown. We Investigated the renal effects of LDD in ten burn C A patients (mean :I: SEM age and %total body surface burned: 30.2 _ 3.3 years and 53.4% :1: 7%) and six controls (mean age; 20.2 l 0.5 years). Administration of LDD significantly Increased glomerular filtration rate, effective renal plasma flow, sodium _ excretion, and urine flow in the controls and effective renal plasma flow, urine flow, WE heart rate, and cardiac index In the patients. The chronotropic effect of dopamine W r , , , appears to be a principal contributor to the patients' increased effective renal plasma U , flow. Sodium excretion was increased by LDD only In the patients in whom the pre-00 . INTRAVENOUS DOPAMINE is frequently adminis-effects is an increase in urine output and sodium excre-"tered to critically ill patients, with its wide use based tion.2 -' -upon the range of effects, which are infusion rate deThese renal-specific dopamine effects have encouraged So pendent. The dose-related pharmacologic actions result intensivists to extrapolate the results from normal sub-: 5 from selective stimulation of alpha-, beta-, and dopa-jects to critically ill patients. The finding of altered r. $ mine-adrenergic receptors. In normal huvrns, infusion receptor sensitivity to low-dose dopamine in some parates less than 1 ug/kg/min primarily stimulate dopa-tient populations questions the validity of this assumpmine-1 and dopamine-2 receptors, resulting in vasodila-tion,' and few data exist that can support wide-scale use S. . tation and increased blood flow to renal, mesenteric, of low-dose dopamine. The objective of this study was to cerebral, and coronary vascular beds. As the dosage is evaluate the effect of low-dose dopamine therapy in increased, additional stimulation of beta-adrenergic re-thermally injured patients by documenting its effect on &0ceptors produces direct positive inotropic and chrono-effective renal plasma flow, glomerular filtration rate, tropic effects with a concomitant increase in cardiac sodium excretion, free water clearance, and cardiac func-V=4 output. When infusion rates exceed 10 mg/kg/min, alpha-tion. This study focused on severely burned patients 0 1 and alpha-2 receptor stimulation is affected and sys-since we have previously reported a significant decrement temic vascular resistance increases, in blood volume with concomitant changes in hormonal Renal blood flow alterations are a consequence of control mechanisms despite a hyperdynamic circulation.

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