OMFIL 20 (Omeprazole capsules)

OMFIL 20 (Omeprazole capsules)

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OMFIL 20 (Omeprazole capsules)

Omeprazole is a proton pump inhibitor. It inhibits secretion of acid by irreversibly blocking the enzyme system of hydrogen/potassium adenosine triphosphatase (H+/K+ ATPase in gastric parietal cells.

The exact mechanism of action of omeprazole is still not certain. The proton pump is present in a wide variety of animal species and although it is primarily found in gastric parietal cells, there is some evidence that is also exists in the colon and jejunum. In gastric mucosa the enzyme is found on the apical membrane and in tubulovesicles lining the secretory canaliculi of the parietal cell. As a weak base, omeprazole accumulates in acid spaces and thus selectivity to the gastric H+ / K+-ATPase is afforded in-vivo, even though in vitro binding has been noted in dog kidneys.

The site of action of omeprazole is clearly distal to cAMP activation and it seems that binding of omeprazole to the proton pump results in inhibition of acid secretion. The drug is activated at the low pH found in secretory canaliculi allowing binding with sulphydryl groups on the enzyme. Omeprazole may bind to other ATPases, but the unique acidic pH of the parietal cell tubulovesicles encourages both accumulation and activation of the drug.

Therapeutic indications

Duodenal ulcer: Omeprazole is indicated for short-term treatment of active duodenal ulcer

Gastric ulcer: Omeprazole is indicated for the short-term treatment (4-8) weeks of active benign gastric ulcer

Symptomatic gastroesophageal reflux disease (GERD): Omeprazole is indicated for the treatment of heartburn and other symptoms associated with GERD.

Erosive esophagitis: Omeprazole is indicated for the short-term treatment (4-8) weeks of erosive esophagitis which has been diagnosed by endoscopy

Maintenance of healing of erosive esophagitis: Omeprazole is indicated to maintain healing of erosive esophagitis

Pathological hypersecretory conditions: Omeprazole is indicated for the long-term treatment of pathological hypersecretory conditions (e,g Zollinger-Ellison syndrome, multiple endocrine adenoma and systemic mastocytosis).

Posology and method of administration

Omeprazole capsules should be taken before meals

Duodenal ulcer: Short-term treatment of active duodenal ulcer, the recommended adult dose of omeprazole is 20mg once daily. Most patients heal within 4 weeks. Some patients may require an additional four weeks of therapy. Reduction of the risk of Duodenal ulcer recurrence, combination therapy with clarithromycin days 1-14; omeprazole 40mg q.d. (in the morning) plus clarithromycin 500mg t.i.d. Days 15-28: omeprazole 20mg q.d

Gastric ulcer: The recommended adult oral dose is 40mg once a day for 4-8 weeks

Gastroesophageal Reflux Disease (GERD): The recommended adult oral dose for the treatment of patients with symptomatic GERD and no esophageal lesions is 20mg daily for up to 4 weeks. The recommended adult oral dose for the treatment of patients with erosive esophagitis and accompanying symptoms due to GERD is 20mg daily for 4 to 8 weeks.

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Maintenance of healing of erosive esophagitis: The recommended adult oral dose is 20mg daily

Pathological hypersecretory conditions: The dosage of omeprazole in patients with pathological hypersecretory conditions varies with the individual patient. The recommended adult oral starting dose is 60mg once a day. Doses should be adjusted to individual patients needs and should continue for as long as clinically indicated. Doses up to 120mg three times daily have been administered. Daily dosages greater than 80mg should be administered in divided doses. Some patients with Zollinger-Ellison syndrome have been treated continuously for more than 5 years. No dosage adjustment is necessary for patients with renal impairment, hepatic dysfunction or for the elderly. Omeprazole delayed-release capsules should be taken before meals.

Children: Not recommended

Drug interactions

Omeprazole can prolong the elimination of diazepam, warfarin and phenytoin, drugs that are metabolized by oxidation in the liver. Although in normal subjects no interactions with theophylline or propranolol was found, there have been clinical reports of interactions with other drugs metabolized via the cytochrome P-450 system (e.g., cyclosporine, disulfiram, benzodiazepines). Patients should be monitored to determine if it is necessary to adjust the dosage of these drugs when taken concomitantly with omeprazole. Because of its profound and long lasting inhibition of gastric acid secretion, it is theoretically possible that omeprazole may interfere with absorption of drugs where gastric pH is an important determinant of their bioavailability (e.g., ketoconazole, ampicillin esters and iron salts)

Pregnancy

Sporadic reports have been received of congenital abnormalities occurring in infants born to women who have received omeprazole during pregnancy. Omeprazole should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Nursing mothers

Omeprazole is excreted in breast-milk but it not likely to influence the child when therapeutic doses are used.

Pediatric use

Safety and effectiveness in children have not been established

Effects on ability to drive and use machines

Omeprazole is not likely to affect the ability to drive or use machines

Undesirable effects

Diarrhoea, skin rashes and headache are reported frequently. Other undesirable effects reported rarely include myalgia, blood disorders including leucopenia and thrombocytopenia.

Contraindications

Known hypersensitivity to omeprazole

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