About Ranitidine and Domperidone
Ranitidine and Domperidone are together used to treat gastroesophageal reflux disorder not responding adequately to ranitidine as well as used in peptic ulcer disease. It inhibits basal and stimulated secretion of gastric acid, reducing both the volume and the acid and pepsin content of the secretion. It promotes the movement of food in the stomach to prevent nausea or vomiting. It is Manufactured and sold in India as R Loc D, Rantac DOM, Ranit D.
It is a Combination of two medicines, Ranitidine Hydrochloride and Domperidone. Ranitidine is a specific rapidly acting histamine H2 receptor-antagonist. It inhibits basal and stimulated secretion of gastric acid, reducing both the volume of the acid and pepsin content of the secretion. Domperidone is a dopamine antagonist with anti-emetic properties, Domperidone does not readily cross the blood-brain barrier. Domperidone promotes the release of prolactin from the pituitary.
For the treatment of GERD not responding adequately to Ranitidine.
Dose and Method of Administration
Adult and Children over 12 year: 1 tablet bid or as directed by the physician. The Tablet should be administered orally.
• Hypersensitivity to the active substance or to any of the excipients.
• Prolactin-releasing pituitary tumour (prolactinoma).
• When stimulation of the gastric motility could be harmful e.g in patients with gastro- intestinal haemorrhage, mechanical obstruction or perforation.
• In patients with moderate or severe hepatic impairment.
• In patients who have known existing prolongation of cardiac conduction intervals, particularly QTc, patients with significant electrolyte disturbances or underlying cardiac diseases such as congestive heart failure.
• Co-administration with QT-prolonging drugs, at the exception of apomorphine.
• Co-administration with potent CYP3A4 inhibitors (regardless of their QT prolonging effects).
Warning and Precautions
• The possibility of malignancy should be excluded before the commencement of therapy in patients with gastric ulcer and in patients of middle age and over with new or recently changed dyspeptic symptoms) as treatment may mask symptoms of gastric carcinoma.
• Ranitidine present in fixed-dose combination of Ranitidine and Domperidone is excreted via the kidney and so plasma levels of the drug are increased in patients with renal impairment. The elimination half-life of domperidone is prolonged in severe renal impairment.
• Regular supervision of patients who are taking non-steroidal anti-inflammatory drugs concomitantly with fixed-dose combination of Ranitidine and Domperidone is recommended, especially in the elderly and in those with a history of peptic ulcer.
• Fixed-dose combination of Ranitidine and Domperidone should be avoided in patients with a history of acute porphyria as it may precipitate attacks of porphyria.
• In patients such as the elderly, persons with chronic lung disease, diabetes or the immune compromised, there may be an increased risk of developing community-acquired pneumonia.
• QT interval on the electrocardiogram has been reported with Domperidone
• Epidemiological studies showed that domperidone present in fixed dose combination of Ranitidine and Domperidone was associated with an increased risk of serious ventricular arrhythmias or sudden cardiac death.
• FDC of Ranitidine and Domperidone is contraindicated in patients with known existing prolongation of cardiac conduction intervals, particularly QTc, in patients with significant electrolyte disturbances (hypokalaemia, hyperkalaemia, hypomagnesaemia), or bradycardia, or in patients with underlying cardiac diseases such as congestive heart failure due to increased risk of ventricular arrhythmia. Treatment should be stopped if signs or symptoms occur that may be associated with cardiac arrhythmia and the patients should consult their physician. Patients should be advised to promptly report any cardiac symptoms.
• Domperidone present in fixed-dose combination of Ranitidine and Domperidone is contra-indicated with QT-prolonging drugs including apomorphine unless the benefit of the co-administration with apomorphine outweighs the risks.
Ranitidine : Ranitidine has the potential to affect the absorption, metabolism or renal excretion of other drugs. The altered pharmacokinetics may necessitate dosage adjustment of the affected drug or discontinuation of treatment
Interactions occur by several mechanisms including
1) Inhibition of cytochrome P450-linked mixed-function oxygenase system
2) Competition for renal tubular secretion
3) Alteration of gastric pH
Domperidone The main metabolic pathway of domperidone is through CYP3A4. In vitro data suggest that the concomitant use of drugs that significantly inhibit this enzyme may result in increased plasma levels of domperidone. Increased risk of occurrence of QT-interval prolongation, due to pharmacodynamic and/or pharmacokinetic interactions.