Omeprazole (omeprazole)
Last reviewed · Source: First Databank (FDB) drug data
Overview
Omeprazole, commonly referred to as an acid- or proton-pump inhibitor, is a gastric antisecretory agent.
Omeprazole is a substituted benzimidazole gastric antisecretory agent. Omeprazole binds to hydrogen/potassium adenosine triphosphatase (H+/K+-exchanging ATPase) in gastric parietal cells; inactivation of this enzyme system (also known as the proton, hydrogen, or acid pump) blocks the final step in the secretion of hydrochloric acid by these cells. Omeprazole inhibits basal and stimulated gastric acid secretion; in addition, because the drug inhibits the final step in the secretory pathway, it inhibits such secretion regardless of the stimulus.
The degree of inhibition of gastric acid secretion is related to the dosage and duration of therapy of omeprazole.
Following oral administration of omeprazole, peak plasma concentrations and AUC are dose proportional up to doses of 40 mg. Peak plasma concentrations and AUC exert a greater than linear response for doses >40 mg because of a saturable first-pass effect. Because the omeprazole molecule is acid labile, the drug is administered orally as a delayed-release capsule or oral suspension or as a buffered immediate-release capsule or oral suspension.
The suspension is also commercially available as a kit containing omeprazole and sodium bicarbonate. The commercially available omeprazole delayed-release capsules increase oral bioavailability of the drug by delaying absorption until after the capsule leaves the stomach; peak plasma concentrations of omeprazole occur 30 minutes to 3.5 hours after administration. The absolute bioavailability of omeprazole delayed-release capsules is 30-40% at doses of 20--40 mg, which is largely due to presystemic metabolism; with repeated administration, bioavailability of the capsules increases slightly.
Following repeated administration of omeprazole magnesium delayed-release oral suspension, peak plasma concentrations are attained within 1.5--2 hours. Mean peak plasma concentrations of omeprazole and sodium bicarbonate preparations occur at about 30 minutes after oral administration. Relative to administration 1 hour before a meal, omeprazole exposure is reduced when omeprazole and sodium bicarbonate preparations are administered 1 hour following a meal.
Following comparable weight-based doses, children 2-5 years of age have lower AUCs than children 6-16 years of age or adults, which are comparable.
Omeprazole is approximately 95% protein bound. Omeprazole undergoes extensive metabolism via the cytochrome P-450 (CYP) enzyme system, primarily via CYP2C19, and to a lesser extent via CYP3A4. Following oral administration of a single dose of omeprazole, approximately 77% of the dose is excreted in urine as various metabolites; the remainder of the dose is excreted in feces.
In healthy individuals, the half-life of delayed-release omeprazole preparations is 30 minutes to 1 hour. The half-life of omeprazole and sodium bicarbonate preparations is approximately 1 hour.
Following oral administration of omeprazole, inhibition of gastric acid secretion is apparent within 1 hour, peaks within 2 hours, and persists for up to 72 hours. Inhibition of gastric acid secretion increases with continuous drug administration and reaches a plateau after about 4 days of omeprazole therapy. Following discontinuance of omeprazole therapy, gastric acid secretion returns to baseline over a 3-5 day period.
USES: Omeprazole is used to treat certain stomach and esophagus problems (such as acid reflux, ulcers). It works by decreasing the amount of acid your stomach makes. It relieves symptoms such as heartburn, difficulty swallowing, and cough.
This medication helps heal acid damage to the stomach and esophagus, helps prevent ulcers, and may help prevent cancer of the esophagus. Omeprazole belongs to a class of drugs known as proton pump inhibitors (PPIs). If you are self-treating with this medication, over-the-counter omeprazole products are used to treat frequent heartburn (occurring 2 or more days a week).
Since it may take 1 to 4 days to have full effect, these products do not relieve heartburn right away. For over-the-counter products, carefully read the package instructions to make sure the product is right for you. Check the ingredients on the label even if you have used the product before.
The manufacturer may have changed the ingredients. Also, products with similar brand names may contain different ingredients meant for different purposes. Taking the wrong product could harm you.
Generic name: omeprazole
Pronunciation: (oh-MEP-ra-zole)
Reference product & biosimilars
No reference, biosimilar or interchangeable associated with this drug.
Today’s intelligence on Omeprazole
Indications
The following indications are listed for Omeprazole:
- Duodenal Ulcer
- Duodenal Ulcer Due To H. Pylori
- Erosive Esophagitis
- Gastric Hypersecretion With Systemic Mastocytosis
- Gastric Ulcer
- Gastroesophageal Reflux Disease
- Heartburn
- Helicobacter Pylori Gastritis
- Maintenance Of Healing Erosive Esophagitis
- Pathological Gastric Acid Hypersecretory Condition
- Zollinger-Ellison Syndrome
Also known as: Adenomatosis Partial Multiple Endocrine, Brash, Campylobacter Gastritis, Du Due To H. Pylori, Duodenal Ulcer Due To Campylobacter Pylori, Duodenal Ulcer Due To Helicobacter Pylori, Gastric Acid Hypersecretory Conditions Due To Disease, Gastro-Esophageal Reflux, Ge Reflux Disease, H. Pylori Gastritis, Pancreatic Ulcerogenic Tumor Syndrome, Pathological Gastric Acid Hypersecretory States, Pathological Hypersecretion State, Pathological Hypersecretory Condition, Pyrosis, Systemic Mast Cell Disease With Gastric Hypersecretion, Z-E Syndrome.
Dosing
Dosage of omeprazole magnesium is expressed in terms of omeprazole.
Omeprazole delayed-release and immediate-release capsules are administered orally; oral suspensions of the drug are administered orally or through a gastric tube. To avoid decomposition of omeprazole in the acidic pH of the stomach, the commercially available delayed-release capsules and delayed-release oral suspension contain enteric-coated granules of the drug. Immediate-release capsules, immediate-release oral suspension, and the kit for oral suspension (Konvomep(R)) all contain sodium bicarbonate to protect the drug from acid degradation.
Omeprazole magnesium is also available in fixed-combination capsules containing amoxicillin and rifabutin (Talicia(R)). A co-packaged product containing delayed-release omeprazole capsules, clarithromycin tablets, and amoxicillin capsules (Omeclamox-Pak(R)) is also commercially available. See the full prescribing information for administration of these combination products.
Antacids may be administered concomitantly with delayed-release preparations of omeprazole.
For patients receiving continuous feedings via a nasogastric or orogastric tube, enteral feeding should be stopped temporarily for 3 hours before and for 1 hour after administration of preparations of omeprazole oral suspension.
Store omeprazole delayed-release capsules in tight containers or the original carton at 20-25degreesC; protect from light and moisture. Store packets of omeprazole powder for delayed-release suspension at 25degreesC (excursions permitted from 15-30degreesC). Store immediate-release capsules in tight, light-resistant containers at 20-25degreesC and protect from moisture. Store packets of omeprazole powder for immediate-release suspension protected from light and moisture at 25degreesC (excursions permitted from 15-30degreesC). Store omeprazole and sodium bicarbonate powder kit for oral suspension (Konvomep(R)) at 2-8degreesC protected from light; do not freeze.
No dosing information is available for this tab.
No dosing information is available for this tab.
Drug interactions
In vivo, omeprazole is a substrate and inhibitor of cytochrome P-450 (CYP) isoenzyme 2C19, and a substrate of CYP3A4. Omeprazole is also an inhibitor of CYP2C19 in vitro.
When co-packaged delayed-release omeprazole capsules, clarithromycin tablets, and amoxicillin capsules (Omeclamox-Pak(R)) are prescribed, drug interactions should be considered for each individual component. Refer to the Omeclamox-Pak(R) prescribing information for drug interaction information.
There are no contraindication interactions for this drug.
There are no severe interactions for this drug.
There are no moderate interactions for this drug.
Contraindications
*Known hypersensitivity reactions (including anaphylaxis) to omeprazole, esomeprazole, or other substituted benzimidazoles (e.g., lansoprazole, pantoprazole, rabeprazole), or any ingredient in the formulation. Hypersensitivity reactions may include anaphylaxis, anaphylactic shock, angioedema, bronchospasm, acute tubulointerstitial nephritis, and urticaria.
*Concomitant use of proton-pump inhibitors (PPIs), including omeprazole, and rilpivirine is contraindicated.
There are no contraindication contraindications for this drug.
There are no severe contraindications for this drug.
There are no moderate contraindications for this drug.
Adverse reactions
Adverse effects reported in >=2% of adults receiving omeprazole in clinical trials include headache, abdominal pain, nausea, diarrhea, vomiting, and flatulence.
Adverse effects reported in pediatric patients 2--16 years of age receiving omeprazole were similar to those reported in adults, except for more frequently reported respiratory system events and fever.
There are no severe adverse reactions for this drug.
There are no less severe adverse reactions for this drug.
Precautions
No enhanced messaging available.
Safety and efficacy of omeprazole magnesium delayed-release oral suspension have been established for the treatment of erosive esophagitis due to acid-mediated gastroesophageal reflux disease (GERD) in pediatric patients >=1 month of age. Safety and efficacy of omeprazole magnesium delayed-release oral suspension have also been established for the treatment of symptomatic GERD and maintenance of healing of erosive esophagitis in pediatric patients 1-16 years of age. Safety and efficacy of omeprazole delayed-release capsules have been established for the treatment of symptomatic GERD and maintenance of healing of erosive esophagitis in pediatric patients 2-16 years of age. Use in pediatric patients is supported by adequate and well-controlled studies in adults and uncontrolled safety, efficacy, and pharmacokinetic studies in pediatric and adolescent patients.
Safety and efficacy of omeprazole magnesium delayed-release oral suspension are not established in pediatric patients <1 month of age or for other uses in pediatric patients. Safety and efficacy of omeprazole delayed-release capsules in pediatric patients <1 year of age for the treatment of symptomatic GERD or maintenance of healing of erosive esophagitis have not been established. Safety and efficacy of omeprazole delayed-release capsules have not been established in pediatric patients for the treatment of active duodenal ulcer, H. pylori eradication to reduce the risk of duodenal ulcer recurrence, treatment of active benign gastric ulcer, or pathological hypersecretory conditions. Safety and efficacy of omeprazole immediate-release capsules and oral suspension have not been established in pediatric patients.
Safety and efficacy of omeprazole and sodium bicarbonate powder kit for oral suspension (Konvomep(R)) have not been established in pediatric patients.
Safety and efficacy of co-packaged omeprazole delayed-release capsules, clarithromycin tablets, and amoxicillin capsules (Omeclamox-Pak(R)) have not been established in pediatric patients with H. pylori.
Respiratory adverse reactions and accidental injuries have been reported more frequently in pediatric patients of all ages than in adults. Otitis and fever have been reported more frequently in patients less than one year of age and patients from one month to less one year to less than 2 years of age, respectively, than in other pediatric and adult patients.
Reproductive studies in rats and rabbits using omeprazole dosages during organogenesis of up to 138 and 69.1 mg/kg daily (about 34 times the human dosage of 40 mg daily based on body surface area (BSA)), respectively, have not revealed evidence of teratogenicity. However, in rabbits given omeprazole dosages of 6.9-69.1 mg/kg daily during organogenesis (about 3.4-34 times the human dosage of 40 mg daily based on BSA), dose-related increases in embryolethality, fetal resorptions, and pregnancy loss occurred. In rats, dose-related embryo/fetal toxicity and postnatal developmental toxicity were observed in offspring resulting from administration of omeprazole in dosages of 13.8-138 mg/kg daily (about 3.4-34 times the human dosage of 40 mg daily based on BSA) prior to mating through the lactation period.
Reproductive studies of oral esomeprazole (an enantiomer of omeprazole) in rats and rabbits during organogenesis using dosages approximately 68 and 42 times the usual human dosage of 40 mg daily based on BSA, did not reveal evidence of embryo/fetal toxicity. When administered through most of pregnancy and lactation, effects on bone morphology were observed in rat offspring at dosages approximately 34 times the human dosage of 40 mg daily based on BSA of esomeprazole; however, when confined to administration during the gestational period only, no effects on bone morphology were observed in another study.
There are no adequate and well controlled studies using omeprazole in pregnant women. Available epidemiologic data have not demonstrated an increased risk of major congenital malformations or other adverse pregnancy outcomes with first trimester exposure to omeprazole. Reproductive studies in rats and rabbits using omeprazole dosages approximately 3.4-34 times the human dosage of 40 mg daily (based on BSA) resulted in dose-dependent increases in embryolethality.
A population-based retrospective cohort epidemiologic study using data from the Swedish Medical Birth Registry reported on outcomes in infants whose mothers used omeprazole during pregnancy; most (about 86%) were exposed to omeprazole during the first trimester, 5% during and beyond the first trimester, and about 14% were exposed only after the first trimester of pregnancy. The number of infants exposed to omeprazole in utero with any malformation, low birth weight, low Apgar score, or hospitalization was similar to the number in this population. The number of infants born with ventricular septal defects and the number of stillborn infants was slightly higher in the omeprazole-exposed infants than the expected number in this population.
In a population-based retrospective cohort study in Denmark reporting on 1800 live births whose mothers received omeprazole during the first trimester and 837,317 live births whose mothers did not receive a PPI, the overall rate of birth defects was 2.9% in infants whose mothers received omeprazole during the first trimester and 2.6% in infants born to mothers not exposed to any PPI during the first trimester.
In a retrospective cohort study, the incidence of congenital malformations in 689 women who received omeprazole or histamine H2-antagonists in the first trimester of pregnancy was compared with a control group of women who were not exposed to acid-suppressant drugs. The malformation rate associated with histamine H2-antagonists exposure was 5.5%, the malformation rate for nonexposed women was 4.1%, and the malformation rate associated with omeprazole exposure was 3.6%.
A small prospective cohort study followed women exposed to omeprazole (89% during the first trimester) during pregnancy; major congenital malformations occurred in 4% of live births in omeprazole-exposed women, 2.8% of disease-paired controls, and 2% exposed to non-teratogenic agents. Rates of spontaneous and elective abortions, preterm deliveries, gestational age at delivery, and mean birth weight were similar among the groups.
The manufacturers state that several studies reported that adverse short-term effects were not observed in infants when a single oral or IV dose of omeprazole was administered to pregnant women as premedication for cesarean section under general anesthesia.
Available data on sodium bicarbonate administration during pregnancy have not identified a drug-associated risk of major fetal malformations or miscarriage.
Limited data suggest omeprazole is distributed into human milk. The effects of omeprazole on milk production and on the breast-fed infant are unknown. Consider the developmental and health benefits of breast-feeding along with the mother's clinical need for the drug and any potential adverse effects on the breast-fed infant from omeprazole or from the underlying maternal condition.
Although the elimination rate of omeprazole is somewhat decreased in geriatric patients and the bioavailability increased, no adjustment of the usual recommended dosage is required in geriatric patients.
In US and European clinical trials, more than 2000 patients treated with omeprazole were >=65 years of age. Although no overall differences in efficacy or safety were observed between geriatric and younger patients, and other clinical experience revealed no evidence of age-related differences, the possibility that some older patients may exhibit increased sensitivity to the drug cannot be ruled out.
ICD codes
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Last reviewed · Source: First Databank (FDB) drug data
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