1. Clinical Overview
Domperidone is a dopamine D2 and D3 receptor antagonist with antiemetic and prokinetic properties. It acts as a potent peripheral dopamine antagonist, blocking dopamine receptors in the chemoreceptor trigger zone (CTZ) and the upper gastrointestinal tract. Unlike metoclopramide, it does not readily cross the blood-brain barrier, significantly reducing the risk of extrapyramidal side effects. It is widely used in the Indian market for the management of nausea, vomiting, and functional dyspepsia.
| Onset | Duration | Bioavailability |
|---|---|---|
| Oral: 30-60 minutes. Parenteral: 10-30 minutes. | Approximately 6-8 hours. | Oral: Approximately 13-17% due to significant first-pass metabolism. |
2. Mechanism of Action
Domperidone competitively blocks peripheral dopamine D2 and D3 receptors located in the chemoreceptor trigger zone (CTZ) outside the blood-brain barrier and in the upper gastrointestinal tract. This blockade inhibits the nausea/vomiting reflex triggered by dopamine. In the GI tract, it increases lower esophageal sphincter pressure, enhances gastroduodenal peristalsis and coordination, and accelerates gastric emptying, without stimulating gastric acid secretion.
3. Indications & Uses
- Symptomatic treatment of nausea and vomiting of various origins (e.g., drug-induced, infection-related).
- Management of functional dyspepsia with symptoms of postprandial fullness, early satiety, epigastric pain, or burning.
4. Dosage & Administration
Adult Dosage: Oral: 10-20 mg (1-2 ml of 10mg/ml suspension) three to four times daily, preferably 15-30 minutes before meals and at bedtime. Maximum daily dose: 30 mg (3 ml) in patients <60 kg or with mild renal impairment; 40 mg (4 ml) in patients >60 kg with normal renal/hepatic function.
Administration: Shake the oral suspension well before use. Use the measuring cup or oral syringe provided for accurate dosing. Administer 15-30 minutes before meals and at bedtime for optimal prokinetic effect. For nausea/vomiting alone, can be taken as needed. Do not exceed the prescribed dose or duration.
5. Side Effects
Common side effects may include:
- Headache
- Dry mouth
- Diarrhea
- Abdominal cramps
- Dizziness
- Skin rash or itching
- Increased serum prolactin levels leading to galactorrhea, breast enlargement/tenderness, menstrual irregularities
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Ketoconazole, Fluconazole, Itraconazole, Voriconazole | Potent CYP3A4 inhibitors. Dramatically increase domperidone plasma levels, leading to high risk of QT prolongation and arrhythmias. | Contraindicated |
| Clarithromycin, Erythromycin, Telithromycin | Potent CYP3A4 inhibitors and also prolong QT. Concomitant use is contraindicated. | Contraindicated |
| Protease Inhibitors (Ritonavir, Saquinavir) | Potent CYP3A4 inhibitors. Contraindicated. | Contraindicated |
| Amiodarone, Dronedarone, Quinidine, Sotalol | Other QT-prolonging drugs. Additive risk of life-threatening arrhythmias. Avoid combination. | Major |
| Anticholinergics (e.g., Atropine, Hyoscine) | May antagonize the gastrointestinal prokinetic effects of domperidone. | Moderate |
| Dopamine Agonists (e.g., Bromocriptine, Levodopa) | Domperidone may antagonize the therapeutic effect of these drugs in Parkinson's disease. | Moderate |
| Warfarin | Theoretical interaction due to protein binding displacement; monitor INR. | Minor |
7. Patient Counselling
- DO take the medicine exactly as prescribed by your doctor, usually 15-30 minutes before meals.
- DO shake the oral suspension bottle well before measuring each dose.
- DO use the measuring device (cup/syringe) provided with the medicine for accuracy.
- DO inform your doctor if you have a history of heart, liver, or kidney problems.
- DO NOT exceed the prescribed dose or duration of treatment.
- DO NOT take this medicine if you are also taking antifungal medicines (like ketoconazole) or certain antibiotics (like clarithromycin).
- DO NOT consume grapefruit juice while on this medication.
8. Toxicology & Storage
Overdose: Symptoms may include agitation, seizures, altered consciousness, extrapyramidal reactions (especially in children), confusion, somnolence, and cardiac effects such as palpitations, QT prolongation, and arrhythmias.
Storage: Store at room temperature (15-25°C), protected from light and moisture. Keep the bottle tightly closed. Do not freeze the oral suspension. Keep out of reach and sight of children. Discard any unused suspension after the expiry date printed on the label.