Overview
Domperidone is a dopamine antagonist that enhances gastrointestinal motility by blocking dopamine receptors in the gastrointestinal tract and chemoreceptor trigger zone. It is used to treat symptoms of gastroparesis, nausea, and vomiting, though its use in the United States is restricted due to cardiac risks. The medication increases lower esophageal sphincter pressure and accelerates gastric emptying.
Mechanism of Action
Domperidone acts as a selective peripheral dopamine D2 and D3 receptor antagonist. It blocks dopamine receptors in the gastrointestinal tract, enhancing gastric motility and coordination, and inhibits dopamine receptors in the chemoreceptor trigger zone to reduce nausea and vomiting without crossing the blood-brain barrier significantly.
Indications
- Symptomatic treatment of upper gastrointestinal motility disorders such as gastroparesis
- Management of nausea and vomiting
- Relief of symptoms like postprandial fullness, early satiety, bloating, and epigastric discomfort
Common Doses
- 10 mg tablet
- 1 mg/mL oral suspension
- Combination injectable forms for veterinary use (as in Ovaprim with sGnRHa)
Dosage
Typical adult dosage is 10 mg taken three to four times daily, 15-30 minutes before meals and at bedtime. Maximum daily dose should not exceed 40 mg. Dosage may be adjusted based on clinical response and tolerability.
Contraindications
- Known hypersensitivity to domperidone
- Prolactin-releasing pituitary tumor (prolactinoma)
- Conditions where gastrointestinal stimulation might be dangerous (e.g., gastrointestinal hemorrhage, mechanical obstruction, perforation)
- Concomitant use with QT-prolonging drugs or in patients with known QT prolongation or cardiac conditions
Side Effects
- Headache
- Dry mouth
- Abdominal cramps
- Diarrhea
- Nervousness
- Dizziness
- Galactorrhea
- Gynecomastia
- Menstrual irregularities
- QT prolongation (serious)
- Cardiac arrhythmias (serious)
Interactions
- Ketoconazole and other strong CYP3A4 inhibitors increase domperidone levels and QT prolongation risk
- Other QT-prolonging drugs (e.g., certain antipsychotics, antiarrhythmics, antibiotics) increase arrhythmia risk
- Anticholinergic drugs may reduce domperidone's gastrointestinal effects
- Dopamine agonists (e.g., bromocriptine) may have reduced efficacy
Counseling Points
- Take 15-30 minutes before meals and at bedtime as directed
- Report any irregular heartbeat, dizziness, or fainting immediately
- Avoid grapefruit juice as it may increase drug levels
- Inform healthcare provider of all medications, especially those affecting heart rhythm
- Do not use for nausea/vomiting without consulting a doctor due to cardiac risks