Indications

Omeprazole is indicated for the treatment of- Gastric and duodenal ulcer NSAID-associated duodenal and gastric ulcer As prophylaxis in patients with a history of NSAID-associated duodenal and gastric ulcer Gastro-esophageal reflux disease Long-term management of acid reflux disease Acid-related dyspepsia Severe ulcerating reflux esophagitis Prophylaxis of acid aspiration during general anesthesia Zollinger-Ellison syndrome Helicobacter pylori-induced peptic ulcer.

Composition

Pharmacology

Omeprazole, a substituted benzimidazole, is an inhibitor of gastric acid secretion. It inhibits gastric acid secretion by blocking hydrogen-potassium-adenosine triphosphatase (H + /K + ATPase) enzyme system in the gastric parietal cell. After oral administration, the onset of the antisecretory effect occurs within one hour, with the maximum effect occurring within two hours and inhibition of secretion lasts up to 72 hours. When the drug is discontinued, secretory activity returns gradually, over 3 to 5 days.

Dosage & Administration

Oral- Benign gastric and duodenal ulcer : 20 mg once daily for 4 weeks in duodenal ulceration, 8 weeks in gastric ulceration; in severe or recurrent cases, dose to be increased to 40 mg daily; maintenance dose for recurrent duodenal ulcer, 20 mg once daily; in prevention of relapse in duodenal ulcer, 10-20 mg daily. NSAID-associated duodenal or gastric ulcer : 20 mg once daily for 4 weeks, continued for further 4 weeks, if not fully healed. 20 mg once daily is used as prophylaxis in patients with a history of NSAID-associated duodenal or gastric ulcers. Gastro-esophageal reflux disease : 20 mg once daily for 4 weeks, continued for further 4-8 weeks, if not fully healed; 40 mg once daily has been given for 8 weeks in gastro-esophageal reflux disease, refractory to other treatment; maintenance dose is 20 mg once daily. Long-term management of acid reflux disease : 10-20 mg daily. Acid-related dyspepsia : 10-20 mg once daily for 2-4 weeks. Prophylaxis of acid aspiration : 40 mg on the preceding evening, then 40 mg 2-6 hours before surgery. Zollinger-Ellison syndrome : Initially 60 mg once daily; usual range 20-120 mg daily (If daily dose is more than 80 mg, 2 divided dose should be used). Helicobacter pylori eradication regimen in peptic ulcer disease : Omeprazole is recommended at a dose of 20 mg twice daily in association with antimicrobial agents as detailed below: Amoxicillin 500 mg and Metronidazole 400 mg both three times a day for one week, or Clarithromycin 250 mg and Metronidazole 400 mg both twice a day for one week, or Amoxicillin 1 g and Clarithromycin 500 mg both twice a day for one week. Paeditaric use in severe ulcerating reflux esophagitis (Child>1 year) : If body-weight 10-20 kg, 10-20 -mg once daily for 4-12 weeks; if body-weight over 20 kg, 20-40 mg once daily for 4-12 weeks. IV Injection- Prophylaxis of acid aspiration : Omeprazole 40 mg to be given slowly (over a period of 5 minutes) as an intravenous injection, one hour before surgery. Duodenal ulcer, gastric ulcer or reflux oesophagitis : In patients with duodenal ulcer, gastric ulcer or reflux oesophagitis where oral medication is inappropriate, Omeprazole IV 40 mg once daily is recommended. Zollinger- Ellison syndrome (ZES) : In patients with Zollinger-Ellison Syndrome the recommended initial dose of Omeprazole given intravenously is 60 mg daily. Higher daily doses may be required and the dose should be adjusted individually. When doses exceed 60 mg daily, the dose should be divided & given twice daily.

Contraindications

Omeprazole is contraindicated in patients with known hypersensitivity to it. When gastric ulcer is suspected, the possibility of malignancy should be excluded before treatment with omeprazole is instituted, as treatment may alleviate symptoms and delay diagnosis.

Side Effects

Omeprazole is well tolerated and adverse reactions have generally been mild and reversible. Skin rash, urticaria and pruritus have been reported. Usually resolving after discontinuation of treatment. In addition photosensitivity, bullous eruption, erythema multiforme, angioedema and alopecia have been reported in isolated cases. Diarrhoea and headache have been reported and may be severe enough to require discontinuation of therapy in a small number of patients. In the majority of cases the symptoms resolved after discontinuation of therapy. Other gastrointestinal reactions have included constipation, nausea/vomiting, flatulence and abdominal pain. Dry mouth, stomatitis and candidiasis have been reported as isolated cases. Paraesthesia has been reported. Dizziness, light headedness and feeling faint have been associated with treatment, but all usually resolve on cessation of therapy. Also reported are somnolence, insomnia and vertigo. Reversible mental confusion, agitation, depression and hallucinations have occurred predominantly in severely ill patients. Arthritic and myalgic symptoms have been reported and have usually resolved when therapy is stopped. In isolated cases, the following have been reported: blurred vision, taste disturbance, peripheral oedema, increased sweating, gynaecomastia, leucopenia, thrombocytopenia, agranulocytosis, pancytopenia, anaphylactic shock, malaise, fever, bronchospasm, encephalopathy in patients with pre-existing severe liver disease, hepatitis with or without jaundice, rarely interstitial nephritis and hepatic failure. Increases in liver enzymes have been observed.

Pregnancy & Lactation

Results from three prospective epidemiological studies indicate no adverse effects of Omeprazole on pregnancy or on the health of the fetus/newborn child. Omeprazole can be used during pregnancy. There is no information available on the passage of Omeprazole into breast milk or its effects on the neonate. Breast-feeding should, therefore, be discontinued, if the use of Omeprazole is considered essential. Use in Children & Adolescents : Safety and effectiveness of Omeprazole have not been established in pediatric patients less than 18 years of age.

Precautions & Warnings

Avoid concomitant use of clopidogrel and omeprazole as the pharmacological activity of clopidogrel is reduced if given concomitantly. Observational studies suggest that proton pump inhibitor (PPI) therapy may be associated with an increased risk for osteoporosis- related fractures of the hip, wrist, or spine. Atrophic gastritis has been noted occasionally in gastric corpus biopsies from patients treated long-term with omeprazole. Concomitant use of PPIs with methotrexate may lead to methotrexate toxicities.

Therapeutic Class

Proton Pump Inhibitor

Storage Conditions

Keep in a dry place away from light and heat. Keep out of the reach of children.