Usage
Domperidone + Famotidine is prescribed for the relief of gastrointestinal symptoms such as dyspepsia, heartburn, nausea, and vomiting associated with gastroesophageal reflux disease (GERD) and other gastrointestinal motility disorders. It is not indicated for long-term use.
Pharmacological Classification:
- Domperidone: Dopamine antagonist, prokinetic agent
- Famotidine: Histamine H2-receptor antagonist
Mechanism of Action:
This combination medication works through two distinct mechanisms:
- Domperidone blocks dopamine receptors in the chemoreceptor trigger zone, increasing gastrointestinal motility and peristalsis, accelerating gastric emptying, and reducing nausea and vomiting. It does not cross the blood-brain barrier significantly.
- Famotidine decreases stomach acid production by blocking histamine H2-receptors in the stomach lining. This helps relieve heartburn and other symptoms associated with excess acid.
Alternate Names
No internationally recognized alternate names exist for the combination itself. However, the individual components have various names:
- Domperidone: Motilium (brand name)
- Famotidine: Pepcid (brand name)
Numerous regional and brand-name variations exist depending on the manufacturer and country.
How It Works
Pharmacodynamics:
- Domperidone: Increases lower esophageal sphincter tone, improves antroduodenal coordination, and enhances gastric emptying. It has antiemetic effects by antagonizing dopamine receptors.
- Famotidine: Inhibits histamine-stimulated gastric acid secretion, reducing basal and nocturnal acid secretion.
Pharmacokinetics:
- Domperidone: Oral absorption is rapid but reduced by food. It is extensively metabolized in the liver (CYP3A4) and has low bioavailability due to first-pass metabolism. Excretion is primarily through feces and to a lesser extent, urine.
- Famotidine: Oral absorption is incomplete. It is minimally metabolized in the liver and primarily excreted unchanged in urine.
Mode of Action:
- Domperidone: Antagonizes dopamine D2 receptors in the periphery, particularly in the gastrointestinal tract.
- Famotidine: Competitively inhibits histamine at H2 receptors of the gastric parietal cells, suppressing gastric acid secretion.
Elimination Pathways:
- Domperidone: Hepatic metabolism (CYP3A4), biliary and renal excretion.
- Famotidine: Primarily renal excretion.
Dosage
Standard Dosage
Adults:
One tablet of Domperidone 10 mg + Famotidine 20 mg, taken orally twice daily, preferably before meals. The maximum daily dose is typically 30 mg of domperidone and 40 mg of famotidine.
Children:
Not recommended for children under 12 years of age. For adolescents (12-18 years), dosing should be individualized based on weight and clinical condition. Pediatric dosing for domperidone is not well established.
Special Cases:
- Elderly Patients: Dose adjustment may be necessary, especially for domperidone, due to potential age-related decrease in hepatic and renal function.
- Patients with Renal Impairment: Dosage adjustment for both drugs is required in moderate to severe renal impairment.
- Patients with Hepatic Dysfunction: Domperidone is contraindicated in moderate to severe hepatic impairment. Famotidine dosage may need adjustment.
- Patients with Comorbid Conditions: Careful consideration and potential dose adjustment are necessary for patients with cardiac conditions, especially QT prolongation.
Clinical Use Cases
Domperidone + Famotidine is not typically indicated for intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. Specific guidelines for these cases do not exist.
Dosage Adjustments
Dosage modifications are based on renal/hepatic function, age, and comorbid conditions. Electrolyte monitoring may be advisable in specific situations.
Side Effects
Common Side Effects:
Headache, dry mouth, diarrhea, constipation, dizziness, abdominal discomfort.
Rare but Serious Side Effects:
Cardiac arrhythmias (including QT prolongation), extrapyramidal symptoms (dystonia, akathisia, parkinsonism), hypersensitivity reactions.
Long-Term Effects:
Long-term use of domperidone is discouraged due to the potential for cardiac side effects. Long-term famotidine use may rarely lead to vitamin B12 deficiency.
Adverse Drug Reactions (ADR):
Angioedema, anaphylaxis, neuroleptic malignant syndrome, cardiac arrest.
Contraindications
- Hypersensitivity to either domperidone or famotidine.
- Gastrointestinal hemorrhage, mechanical obstruction, or perforation.
- Prolactin-releasing pituitary tumor (prolactinoma).
- Concomitant use with QT-prolonging drugs or conditions that predispose to QT prolongation.
- Severe hepatic impairment (for domperidone).
Drug Interactions
- Domperidone: Ketoconazole, itraconazole, erythromycin, other CYP3A4 inhibitors may increase domperidone levels. Antacids may decrease domperidone absorption.
- Famotidine: May interfere with absorption of drugs requiring an acidic environment.
It is essential to review a patient’s full medication list to assess potential interactions.
Pregnancy and Breastfeeding
- Pregnancy: Limited data are available. Use only if potential benefit outweighs risk.
- Breastfeeding: Domperidone is excreted in breast milk in small amounts. Famotidine is considered compatible with breastfeeding.
Drug Profile Summary
- Mechanism of Action: Domperidone: Dopamine antagonist, prokinetic; Famotidine: H2-receptor antagonist.
- Side Effects: Headache, dry mouth, GI disturbances, extrapyramidal reactions (rare).
- Contraindications: Hypersensitivity, GI obstruction/bleeding, prolactinoma, QT prolongation risk, severe hepatic impairment (domperidone).
- Drug Interactions: CYP3A4 inhibitors (domperidone); drugs requiring acidic pH for absorption (famotidine).
- Pregnancy & Breastfeeding: Use with caution; potential for neonatal effects.
- Dosage: Adults: 10mg/20mg twice daily before meals.
- Monitoring Parameters: Cardiac rhythm (ECG), electrolytes.
Popular Combinations
Domperidone + Famotidine is itself a popular combination. It addresses both motility issues and acid secretion in GI disorders.
Precautions
- Baseline ECG for patients with cardiac history.
- Electrolyte monitoring in patients with renal impairment.
- Monitor for extrapyramidal side effects.
- Avoid alcohol and other CNS depressants.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Domperidone + Famotidine?
A: One tablet (10 mg domperidone + 20 mg famotidine) twice daily before meals. Maximum dose: 30 mg domperidone and 40 mg famotidine per day.
Q2: What are the common side effects?
A: Headache, dry mouth, diarrhea, constipation, dizziness, and abdominal discomfort.
Q3: Can it be used in pregnancy?
A: Limited data available. Use only if clearly needed and the potential benefits outweigh the risks.
Q4: Can it be used during breastfeeding?
A: Famotidine is generally considered safe. Domperidone passes into breast milk in small amounts, but adverse effects in infants are rare.
Q5: What are the contraindications?
A: Hypersensitivity, GI obstruction/bleeding, prolactinoma, long QT syndrome, concomitant use with QT prolonging drugs, severe hepatic impairment (domperidone).
Q6: How does it interact with other medications?
A: Domperidone interacts with CYP3A4 inhibitors/inducers. Famotidine can affect the absorption of drugs requiring an acidic pH.
Q7: What monitoring is needed?
A: ECG monitoring, especially in patients with pre-existing cardiac conditions or those taking QT-prolonging drugs. Electrolyte monitoring may be necessary in patients with renal impairment.
Q8: Can it be used in patients with renal impairment?
A: Dosage adjustment is necessary in moderate to severe renal impairment for both components.
Q9: Can it be used in patients with liver disease?
A: Domperidone is contraindicated in moderate to severe hepatic impairment. Famotidine dosage might require adjustment.
Q10: Is this combination safe for long-term use?
A: Long-term use is generally not recommended due to the increased risk of cardiac effects with domperidone.
