1. Clinical Overview
A fixed-dose combination (FDC) product containing Domperidone, a dopamine D2 and D3 receptor antagonist with prokinetic and antiemetic properties, and Esomeprazole, the S-isomer of omeprazole, a proton pump inhibitor (PPI). This combination is primarily used for the management of gastroesophageal reflux disease (GERD) and other acid-peptic disorders where delayed gastric emptying and nausea/vomiting are significant components. Domperidone enhances gastroduodenal motility and coordinates antroduodenal contractions, while Esomeprazole provides profound and long-lasting inhibition of gastric acid secretion by irreversibly blocking the H+/K+ ATPase enzyme system at the secretory surface of the gastric parietal cell.
| Onset | Duration | Bioavailability |
|---|---|---|
| Domperidone: Oral: 30-60 minutes. Esomeprazole: Acid suppression begins within 1 hour; maximal effect occurs after repeated dosing (by day 5). | Domperidone: 4-8 hours. Esomeprazole: >24 hours (due to irreversible binding to proton pump). | Domperidone: Oral: ~15% (due to extensive first-pass metabolism). Esomeprazole: Oral: 64-90% (increased to 89-90% with repeated dosing). |
2. Mechanism of Action
The combination works synergistically. Domperidone acts as a peripheral dopamine D2 and D3 receptor antagonist at the chemoreceptor trigger zone (CTZ) and gastrointestinal tract. It blocks the inhibitory effect of dopamine on gastrointestinal smooth muscle, leading to increased lower esophageal sphincter pressure, enhanced gastric antrum and duodenal contractions, improved gastroduodenal coordination, and accelerated gastric emptying without stimulating gastric acid secretion. Esomeprazole is a proton pump inhibitor that is a weak base and is concentrated in the acidic environment of the parietal cell canaliculi. It is converted to the active sulfenamide form which forms a covalent disulfide bond with cysteine residues on the H+/K+ ATPase (proton pump), irreversibly inhibiting the final step of gastric acid secretion.
3. Indications & Uses
- Gastroesophageal Reflux Disease (GERD) with associated nausea and delayed gastric emptying
- Severe erosive esophagitis (Grade C & D Los Angeles Classification) requiring potent acid suppression and prokinetic support
- Refractory GERD not adequately controlled with PPI alone where gastroparesis is suspected
4. Dosage & Administration
Adult Dosage: One tablet (Domperidone 30mg + Esomeprazole 40mg) once daily, preferably 30-60 minutes before the first major meal of the day (typically breakfast). Duration should be the shortest possible, especially for domperidone component. For GERD, treatment is usually 4-8 weeks.
Administration: Swallow the tablet whole with a glass of water. Do NOT crush, chew, or split the tablet. Should be taken on an empty stomach, at least 1 hour before a meal for optimal absorption of esomeprazole. Antacids may be used concomitantly if needed, but should be taken at least 2 hours apart from this combination.
5. Side Effects
Common side effects may include:
- Headache
- Diarrhea
- Abdominal pain
- Flatulence
- Constipation
- Dry mouth
- Dizziness
- Increased serum prolactin levels (may lead to galactorrhea, breast enlargement, gynecomastia, menstrual irregularities)
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Ketoconazole/Itraconazole/Fluconazole/Voriconazole (Potent CYP3A4 Inhibitors) | Markedly increase domperidone plasma levels, increasing risk of QTc prolongation and cardiac arrhythmias. Contraindicated. | Contraindicated |
| Clarithromycin/Erythromycin/Telithromycin | CYP3A4 inhibitors and also prolong QTc. Synergistic risk of life-threatening arrhythmias with domperidone. | Contraindicated |
| Protease Inhibitors (Ritonavir, Saquinavir) | Potent CYP3A4 inhibitors. Contraindicated with domperidone. | Contraindicated |
| Amiodarone, Procainamide, Quinidine, Sotalol | Drugs that prolong QTc interval. Additive risk of arrhythmias with domperidone. | Major |
| Warfarin | Esomeprazole may inhibit CYP2C19, potentially increasing INR and risk of bleeding. Monitor INR closely. | Moderate |
| Clopidogrel | Esomeprazole (a CYP2C19 inhibitor) may reduce the antiplatelet effect of clopidogrel (a prodrug activated by CYP2C19), potentially increasing cardiovascular risk. Avoid concomitant use if possible. | Major |
| Diazepam, Phenytoin | Esomeprazole may inhibit their metabolism (CYP2C19), increasing plasma levels and risk of toxicity. | Moderate |
| Methotrexate | PPIs may decrease renal clearance of methotrexate, leading to increased methotrexate levels and toxicity. | Moderate |
| Digoxin | Domperidone may increase gastrointestinal motility, potentially reducing digoxin absorption. | Moderate |
| Anticholinergics (e.g., atropine, hyoscine) | May antagonize the gastroprokinetic effects of domperidone. | Moderate |
| Drugs whose absorption is pH-dependent (e.g., Ketoconazole, Itraconazole, Iron salts, Dabigatran) | Esomeprazole reduces gastric acidity, leading to decreased absorption of these drugs. | Moderate |
7. Patient Counselling
- DO take the tablet whole, at least 1 hour before a meal (preferably breakfast).
- DO NOT crush, chew, or break the tablet.
- DO inform your doctor if you have a history of heart, liver, or kidney disease.
- DO NOT take this medicine if you are pregnant, planning pregnancy, or breastfeeding without consulting your doctor.
- DO report any symptoms of irregular heartbeat, dizziness, or fainting immediately.
- DO NOT take with grapefruit juice.
- DO inform all your doctors and dentists that you are taking this medicine, especially before surgery.
8. Toxicology & Storage
Overdose: Domperidone: Agitation, seizures, altered consciousness, extrapyramidal reactions, QTc prolongation, arrhythmias, cardiac arrest. Esomeprazole: Blurred vision, confusion, drowsiness, dry mouth, flushing, headache, nausea, tachycardia, diaphoresis.
Storage: Store below 30°C. Protect from light and moisture. Keep in the original blister pack until use. Keep out of reach and sight of children.