Omeprazole

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.

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.

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.

Direction for use of IV Injection: Omeprazole lyophilized powder and water for injection is for intravenous administration only and must not be given by any other route. Omeprazole IV injection should be given as a slow intravenous injection. The solution for IV injection is obtained by adding 10 ml water for injection to the vial containing powder. After reconstitution the injection should be given slowly over a period of at least 2 to 5 minutes at a maximum rate of 4 ml/minute. Use only freshly prepared solution. The solution should be used within 4 hours of reconstitution.

Direction for use of IV Infusion: Omeprazole IV infusion should be given as an intravenous infusion over a period of 20-30 minutes or more. The contents of one vial must be dissolved in 100 ml saline for infusion or 100 ml 5% Dextrose for infusion. The solution should be used within 12 hours when Omeprazole is dissolved in saline and within 6 hours when dissolved in 5% Dextrose. The reconstituted solution should not be mixed or co-administered in the same infusion set with any other drug.

Due to the decreased intragastric acidity the absorption of ketoconazole may be reduced during Omeprazole treatment as it is during treatment with other acid secretion inhibitors. As Omeprazole is metabolised in the liver through cytochrome P450 it can delay the elimination of diazepam, phenytoin and warfarin. Monitoring of patients receiving warfarin or pheytoin is recommended and a reduction of warfarin or phenytoin dose may be necessary. However concomitant treatment with Omeprazole 20mg daily did not change the blood concentration of phenytoin in patients on continuous treatment with phenytoin. Similarly concomitant treatment with Omeprazole 20mg daily did not change coagulation time in patients on continuous treatment with warfarin. Plasma concentrations of Omeprazole and clarithromycin are increased during concomitant administration. This is considered to be a useful interaction during H. pylori eardication. There is no evidence of an interaction with phenacetin, theophylline, caffeine, propranolol, metoprolol, cyclosporin, lidocaine, quinidine, estradiol, amoxycillin or antacids. The absorption of Omeprazole is not affected by alcohol or food. There is no evidence of an interaction with piroxicam, diclofenac or naproxen. This is considered useful when patients are required to continue these treatments. Simultaneous treatment with Omeprazole and digoxin in healthy subjects lead to a 10% increase in the bioavailability of digoxin as a consequence of the increased intragastric pH.

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.

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.

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.

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.

Proton Pump Inhibitor

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