This combination medication contains a proton pump inhibitor and antidopaminergic agent, prescribed for ulcers, indigestion and acid stomach.
Omeprazole is a proton pump inhibitor used in the treatment of dyspepsia, peptic ulcer disease, gastroesophageal reflux disease,laryngopharyngeal reflux, and Zollinger-Ellison syndrome.
Mechanism of Action: Omeprazole is a selective and irreversible proton pump inhibitor. It suppresses stomach acid secretion by specific inhibition of the H +/K + ATPase system found at the secretory surface of gastric parietal cells. Because this enzyme system is regarded as the acid (proton, or H+) pump within the gastric mucosa, omeprazole will inhibit the final step of acid production.
Omeprazole will also inhibit both basal and stimulated acid secretion irrespective of the stimulus.
Pharmacokinetics : The absorption of omeprazole takes place in the small intestine and is usually completed within 3–6 hr. The systemic bioavailability of omeprazole after repeated dose is about 60%
Omeprazole is completely metabolized by the cytochrome P450 system, mainly in the liver. Identified metabolites are the sulfone, the sulfide and hydroxy-omeprazole, which exert no significant effect on acid secretion. About 80% of an orally given dose is excreted as metabolites in the urine and the remainder is found in the feces, primarily originating from bile secretion.
Adverse effects: The most frequent significant adverse effects occurring in at least 1% of patients include:
- Central nervous system: Headache (7%), dizziness (2%)
- Respiratory: Upper respiratory infection (2%), cough (1%)
- Gastrointestinal: Abdominal pain (5%), diarrhea (4%), nausea (4%), vomiting (3%), flatulence (3%), acid regurgitation (2%), constipation (2%)
- Neuromuscular & skeletal: Back pain (1%), weakness (1%)
- Dermatologic: Rash (2%)
Domperidone: is a peripheral specific blocker of dopamine receptors. It is administered orally, rectally or intravenously. Domperidone is given in order to relieve nausea and vomiting; to increase the transit of food through the stomach; and to increase lactation by release of prolactin.
Mechanism of Action: Domperidone is a peripheral dopamine (D2) and (D3) receptor antagonist. It provides relief from nausea by blocking receptors at the chemo-receptor trigger zone.
Oral absorption of Domperidone is found to be 46.5%. Volume of distribution is found to be 5.7l/Kg and Plasma protein binding is 91-93%. Presystemic metabolism is noted to be 85% and metabolism is reported extensively by liver & Gut. Renal Excretion accounts for major 31% and 66%in feces and plasma half life is 12-16 hr (oral), 7.5 hr (parentral)