The effect of metoclopramide on gastrointestinal motility is antagonised by anticholinergic drugs and narcotic analgesics. Additive sedative effect can occur when metoclopramide is given with alcohol, sedatives, hypnotics, narcotics or tranquilizers.
The finding that metoclopramide releases catecholamines in patients with essential hypertension suggests that it should be used cautiously, if at all, in patients receiving monoamine oxidase inhibitors. Absorption of drugs from the stomach may be diminished (e.g. digoxin) by metoclopramide, whereas the rate and/or extent of absorption of drugs from the small bowel may be increased (e.g. acetaminophen, tetracycline, levodopa, ethanol, cyclosporine).