Omeprazole information from DrugsUpdate
P - Caution when used during pregnancy
L - Caution when used during lactation
FI - Food *
LI - Lab *
Omeprazole is a proton pump inhibitor used in the treatment of dyspepsia, peptic ulcer disease (PUD), gastroesophageal reflux disease (GORD/GERD) and Zollinger-Ellison syndrome. It was first marketed in the US in 1989 by AstraZeneca under the brand names Losec and Prilosec, and is now also available from generic manufacturers under various brand names. AstraZeneca markets omeprazole as Losec, Antra, Gastroloc, Mopral, Omepral, and Prilosec. Omeprazole is marketed as Zegerid by Santarus, Prilosec OTC by Procter & Gamble and Zegerid OTC by Schering-Plough.Omeprazole is one of the most widely prescribed drugs internationally and is available over the counter in some countries. Prilosec contains the active ingredient omeprazole and Prilosec OTC contains the active ingredient omeprazole magnesium.
Pharmacodynamics
Pharmacokinetics
Omeprazole suppresses gastric acid secretion by specific inhibition of the enzyme system hydrogen/potassium adenosine triphosphatase (H+/K+ ATPase) present on the secretory surface of the gastric parietal cell.
Onset
Antisecretory: approx 1 hour; peak effect:0.5-3.5 hours.
Duration
72 hours
Absorption
Rapid but variable (oral); dose-dependent. Bioavailability: Oral: approx 30-40%.
Distribution
Protein-binding: 95%.
Metabolism
Extensively hepatic; converted to hydroxyomeprazole and omeprazole sulfone.
Excretion
Via urine (77%) and bile. Elimination half-life: 0.5-3 hours.
Omeprazole Indications / Omeprazole Uses
Information Not Available
Omeprazole Adverse Reactions / Omeprazole Side Effects
Diarrhoea, nausea, fatigue, constipation, vomiting, flatulence, acid regurgitation, taste perversion, arthralgia, myalgia, urticaria, dry mouth, dizziness, headache, paraesthesia, abdominal pain, skin rashes, weakness, back pain, upper respiratory infection, cough.
Potentially Fatal: Anaphylaxis.
Precautions
Information Not Available
Special Precautions
Exclude malignancy, prolonged use, hepatic impairment. Pregnancy, lactation, children <1 year. Elderly and Asians (increased bioavailability).
Other Drug Interactions
Decreases absorption of itraconazole, ketoconazole, dasatinib, oral iron salts. Decreases levels of nelfinavir. Increases levels of benzodiazepines (e.g. diazepam, midazolam, triazolam), HMG-CoA reductase inhibitor, CYP2C19 substrates (e.g. citalopram, diazepam, methsuximide, phenytoin, propranolol, and sertraline), and CYP2C9 substrates (e.g. bosentan, dapsone, fluoxetine, glimepiride, glipizide, losartan, montelukast, nateglinide, paclitaxel, phenytoin, warfarin, and zafirlukast). Decreased levels/effects with CYP2C19 inducers (e.g. aminoglutethimide, carbamazepine, phenytoin, and rifampin). Decreases excretion of methotrexate. Enhances the adverse/toxic effect of cilostazol. May alter the concentrations/effects of clozapine. Avoid concurrent use with clopidogrel.
Other Interactions
Food Interaction
Absorption may be delayed. St John's wort decreases omeprazole levels. Avoid ethanol (may cause gastric mucosal irritation).
Dosage
Oral
Peptic ulcer
Adult: 20 mg daily as a single dose or 40 mg daily in severe cases. Treatment duration: Duodenal ulcers: 4 weeks; gastric ulcers: 8 weeks. Maintenance: 10-20 mg once daily.
Hepatic impairment: Dose reduction may be necessary.
Oral
NSAID-associated ulceration
Adult: 20 mg daily. Same dose may also be used for prophylaxis of ulceration in patients who require continued NSAID therapy.
Hepatic impairment: Dose reduction may be necessary.
Oral
H.pylori infection
Adult: Dose varies with regimen. As triple therapy: 20 mg bid or 40 mg once daily; requires combination therapy with antibiotics. Therapy is given for 1 week. Omeprazole may be continued for another 4-8 weeks on its own.
Hepatic impairment: Dose reduction may be necesary.
Oral
Gastro-oesophageal reflux disease
Adult: 20 mg once daily for 4 weeks, may continue for another 4-8 weeks if necessary. Maintenance: 10 mg daily.
Child: Neonate, 1 month-2 years: 700 mcg/kg/day, may increase up to 3 mg/kg/day, or 20 mg daily. >2 years: <20 kg: 10 mg once daily; ≥20 kg: 20 mg daily. Doses may be doubled if necessary.
Hepatic impairment: Dose reduction may be necessary.
Oral
Zollinger-Ellison syndrome
Adult: Initially, 60 mg once daily, adjust according to response. Maintenance: 20-120 mg daily. Doses >80 mg are administered usually in 2 divided doses.
Hepatic impairment: Dose reduction may be necessary.
Oral
Prophylaxis of acid aspiration during general anaesthesia
Adult: Initially, 40 mg given the evening before surgery and another 40 mg 2-6 hours before the procedure.
Hepatic impairment: Dose reduction may be necessary.
Oral
Acid-related dyspepsia
Adult: 10 or 20 mg daily for 2-4 weeks.
Hepatic impairment: Dose reduction may be necessary.
Oral
Erosive oesophagitis
Adult: 20 mg/day for 4-8 weeks. Maintenance of healing: 20 mg/day for up to 12 months of total therapy (including treatment period).
Hepatic impairment: Dose reduction may be necessary.
Intravenous
Gastric and duodenal ulcers
Adult: By infusion over 20-30 minutes or slow injection over 5 minutes: 40 mg once daily until oral admin is possible.
Hepatic impairment: Dose adjustment is required; a daily dose of 10-20 mg may be sufficient.
Intravenous
Reflux oesophagitis
Adult: By infusion over 20-30 minutes or slow injection over 5 minutes: 40 mg once daily until oral admin is possible.
Hepatic impairment: Dose adjustment is required; a daily dose of 10-20 mg may be sufficient.
Intravenous
Prophylaxis of acid aspiration during general anaesthesia
Adult: 40 mg, to be given and completed 1 hour before the surgery. May be given via injection over 5 minutes or infusion over 20-30 minutes.
Hepatic impairment: Dose adjustment is required; a daily dose of 10-20 mg may be sufficient.
Reconstitution
The solution for IV injection is obtained by adding to the vial 10 ml of the solvent provided. (No other solvent should be used). The solution should be given over a period of at least 2.5 minutes at a max rate of 4 ml/minute; use within 4 hours of reconstitution. The solution for IV infusion is obtained by dissolving 1 vial in 100 ml saline for infusion or 100 ml 5% dextrose for infusion. The solution should be used within 12 hours when dissolved in saline and within 6 hours when dissolved in 5% dextrose. After reconstitution, start the infusion immediately. The constituted solution should not be mixed or co-administered in the same infusion set with any other drug. Infusion should be given over a period of ≥ 20-30 minutes.
Food(before/after)
MUPS Tablet
May be taken with or without food.
Powder for oral Suspension
Should be taken on an empty stomach. (Take on an empty stomach at least 1 hour before a meal.)
Capsule
Should be taken with food. (Take immediately before a meal.)
List of Contraindications
Omeprazole and Pregnancy
Caution when used during pregnancy
Category C: Either studies in animals have revealed adverse effects on the foetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the foetus.
Omeprazole and Lactation
Caution when used during lactation
Omeprazole and Children
Safety and efficacy not established in children younger than 1 year of age.
Omeprazole and Geriatic
No dosage adjustment is necessary in elderly patients.
Omeprazole and Other Contraindications
Information Not Available
Storage
Intravenous
Store at 15-30 °C. Protect from light.
Oral
Store at 15-30 °C. Protect from light.
Lab interference
Intravenous
Store at 15-30 °C. Protect from light.
Oral
Store at 15-30 °C. Protect from light.
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