From the Guidelines
Metoclopramide is a prokinetic agent that improves stomach emptying and gut movement, and it is primarily used to treat nausea, vomiting, and certain digestive disorders, including gastroparesis. It works by blocking dopamine receptors in the brain's chemoreceptor trigger zone and by stimulating muscle contractions in the upper digestive tract 1. The medication is commonly prescribed for gastroparesis, gastroesophageal reflux disease (GERD), and to prevent nausea and vomiting from chemotherapy or surgery. Metoclopramide typically comes in tablet, liquid, or injectable forms, with standard adult dosing usually being 10mg up to four times daily before meals and at bedtime, though this varies by condition 2. Important side effects to watch for include drowsiness, restlessness, and rarely, serious movement disorders like tardive dyskinesia with long-term use. For this reason, treatment duration is typically limited to 12 weeks or less unless benefits clearly outweigh risks, as recommended by the FDA 3, 4. Some key points to consider when prescribing metoclopramide include:
- It should be reserved for severe cases of gastroparesis that are unresponsive to other therapies 1
- Its use beyond 12 weeks is no longer recommended by the FDA due to the risk of serious adverse effects 2
- Other treatment options include domperidone and erythromycin, which have their own limitations and potential side effects 3, 4
- Metoclopramide should be used cautiously in elderly patients and those with certain neurological conditions, kidney problems, or who take medications that might interact with it.
From the FDA Drug Label
Metoclopramide stimulates motility of the upper gastrointestinal tract without stimulating gastric, biliary, or pancreatic secretions. The effect of metoclopramide on motility is not dependent on intact vagal innervation, but it can be abolished by anticholinergic drugs Metoclopramide increases the tone and amplitude of gastric (especially antral) contractions, relaxes the pyloric sphincter and the duodenal bulb, and increases peristalsis of the duodenum and jejunum resulting in accelerated gastric emptying and intestinal transit. The antiemetic properties of metoclopramide appear to be a result of its antagonism of central and peripheral dopamine receptors
Metoclopramide stimulates the motility of the upper gastrointestinal tract and increases the tone and amplitude of gastric contractions, resulting in accelerated gastric emptying. It also has antiemetic properties due to its antagonism of dopamine receptors. The main effects of metoclopramide are:
- Accelerated gastric emptying
- Increased intestinal transit
- Anti-emetic effects 5
From the Research
Effects of Metoclopramide
- Metoclopramide is a dopamine antagonist that counteracts the effects of dopamine on the upper gastrointestinal tract 6.
- When given alone, metoclopramide increases lower oesophageal sphincter pressure (LOSP) and stimulates gastroduodenal motility and gastric emptying 6.
- Metoclopramide has been found to be of value in certain cases of gastroparesis, and in relieving nausea and vomiting 6.
- It also appears to be useful in the management of reflux oesophagitis 6.
Interaction with Other Substances
- There is no direct evidence of metoclopramide's interaction with other substances in the provided studies, except for its interaction with dopamine 6.
- However, a separate study discusses the interaction of mitochondrial cytochrome P-450 with various substances, including metyrapone and aminoglutethimide, but not metoclopramide 7.