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.