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Look Up > Drugs > Omeprazole
Omeprazole
Pronunciation
U.S. Brand Names
Generic Available
Canadian Brand Names
Pharmacological Index
Use
Pregnancy Risk Factor
Pregnancy/Breast-Feeding Implications
Contraindications
Warnings/Precautions
Adverse Reactions
Overdosage/Toxicology
Drug Interactions
Stability
Mechanism of Action
Pharmacodynamics/Kinetics
Usual Dosage
Dietary Considerations
Administration
Mental Health: Effects on Mental Status
Mental Health: Effects on Psychiatric Treatment
Dental Health: Local Anesthetic/Vasoconstrictor Precautions
Dental Health: Effects on Dental Treatment
Patient Information
Nursing Implications
Dosage Forms
References

Pronunciation
(oh ME pray zol)

U.S. Brand Names
Prilosec™

Generic Available

No


Canadian Brand Names
Losec®

Pharmacological Index

Proton Pump Inhibitor


Use

Short-term (4-8 weeks) treatment of severe erosive esophagitis (grade 2 or above), diagnosed by endoscopy and short-term treatment of symptomatic gastroesophageal reflux disease (GERD) poorly responsive to customary medical treatment; treatment of heartburn and other symptoms associated with GERD; pathological hypersecretory conditions; peptic ulcer disease; gastric ulcer therapy; maintenance of healing of erosive esophagitis; approved for combination use in the eradication of H. pylori in patients with active duodenal ulcer.


Pregnancy Risk Factor

C


Pregnancy/Breast-Feeding Implications

Clinical effects on the fetus: Crosses the placenta

Breast-feeding/lactation: No data available. American Academy of Pediatrics makes NO RECOMMENDATION.


Contraindications

Known hypersensitivity to omeprazole


Warnings/Precautions

In long-term (2-year) studies in rats, omeprazole produced a dose-related increase in gastric carcinoid tumors. While available endoscopic evaluations and histologic examinations of biopsy specimens from human stomachs have not detected a risk from short-term exposure to omeprazole, further human data on the effect of sustained hypochlorhydria and hypergastrinemia are needed to rule out the possibility of an increased risk for the development of tumors in humans receiving long-term therapy. Bioavailability may be increased in the elderly.


Adverse Reactions

1% to 10%:

Central nervous system: Headache (6.9%), dizziness (1.5%)

Dermatologic: Rash (1.5%)

Gastrointestinal: Diarrhea (3%), abdominal pain (2.4%), nausea (2.2%), vomiting (1.5%), constipation (1.1%), taste perversion (<1% to 15%)

Neuromuscular & skeletal: Weakness (1.1%), back pain (1.1%)

Respiratory: Upper respiratory infection (1.9%), cough (1.1%)

<1%: Fever, pain, fatigue, malaise, abdominal swelling, angina, tachycardia, bradycardia, palpitation, hypertension, peripheral edema, pancreatitis, anorexia, irritable colon, flatulence, fecal discoloration, esophageal candidiasis, mucosal atrophy (tongue), dry mouth, benign gastric polyps, gastroduodenal carcinoids, elevated serum transaminases, jaundice, increased serum alkaline phosphatase, liver disease (hepatocellular, cholestatic, mixed), hepatic necrosis, hepatic failure, hepatic encephalopathy, hyponatremia, hypoglycemia, weight gain, muscle cramps, myalgia, muscle weakness, joint pain, leg pain, psychic disturbance, depression, aggression, hallucinations, confusion, insomnia, nervousness, tremor, apathy, somnolence, anxiety, abnormal dreams, vertigo, paresthesia, hemifacial dysesthesia, epistaxis, pharyngeal pain, toxic epidermal necrolysis, Stevens-Johnson syndrome, erythema multiforme, skin inflammation, urticaria, angioedema, pruritus, alopecia, dry skin, increased sweating, tinnitus, interstitial nephritis, urinary tract infection, microscopic pyuria, urinary frequency, elevated serum creatinine, proteinuria, hematuria, glycosuria, testicular pain, gynecomastia, pancytopenia, agranulocytosis, thrombocytopenia, neutropenia, anemia, leukocytosis, hemolytic anemia


Overdosage/Toxicology

Symptoms of overdose include hypothermia, sedation, convulsions, decreased respiratory rate demonstrated in animals only

Treatment is supportive; not dialyzable


Drug Interactions

CYP2C8, 2C9, 2C18, 2C19, and 3A3/4 enzyme substrate; CYP1A2 enzyme inducer; CYP2C19, 2C8, 2C9, and 2C19 enzyme inhibitor, CYP3A3/4 enzyme inhibitor (weak)

Increased toxicity: Diazepam may increase half-life; increased digoxin, increased phenytoin, increased warfarin


Stability

Omeprazole stability is a function of pH; it is rapidly degraded in acidic media, but has acceptable stability under alkaline conditions. Prilosec™ is supplied as capsules for oral administration; each capsule contains omeprazole in the form of enteric coated granules to inhibit omeprazole degradation by gastric acidity.


Mechanism of Action

Suppresses gastric acid secretion by inhibiting the parietal cell H+/K+ ATP pump


Pharmacodynamics/Kinetics

Onset of antisecretory action: Oral: Within 1 hour

Peak effect: 2 hours

Duration: 72 hours

Protein binding: 95%

Metabolism: Extensive in the liver

Half-life: 0.5-1 hour


Usual Dosage

Adults: Oral:

GERD or erosive esophagitis: 20 mg/day for 4-8 weeks

Pathological hypersecretory conditions: 60 mg once daily to start; doses up to 120 mg 3 times/day have been administered; administer daily doses >80 mg in divided doses

Helicobacter pylori: Combination therapy with bismuth subsalicylate, tetracycline, and clarithromycin; or with clarithromycin alone. Adult dose: Oral: 20 mg twice daily

Gastric ulcers: 40 mg/day for 4-8 weeks


Dietary Considerations

Food delays absorption, administer on an empty stomach


Administration

Omeprazole has been administered via a nasogastric (NG) tube for the prevention of stress-related mucosal damage in ventilated, critically ill patients. The contents of one or two 20 mg omeprazole capsules were poured into a syringe; 10-20 mL of an 8.4% sodium bicarbonate solution was withdrawn in the syringe; 30 minutes were allowed for the enteric-coated omeprazole granules to break down. The resulting milky substance was shaken prior to administration. The NG tube was then flushed with 5-10 mL of water then clamped for at least 1 hour. Patients received omeprazole 40 mg once, then 40 mg 6-8 hours later, then 20 mg once daily using this technique.

The manufacturer makes no judgment regarding the safety or efficacy of these practices.


Mental Health: Effects on Mental Status

May cause dizziness; may rarely cause sedation


Mental Health: Effects on Psychiatric Treatment

May inhibit the metabolism of diazepam; monitor for increased sedation


Dental Health: Local Anesthetic/Vasoconstrictor Precautions

No information available to require special precautions


Dental Health: Effects on Dental Treatment

No effects or complications reported


Patient Information

Take as directed, before eating. Do not crush or chew capsules. You may experience anorexia; small frequent meals may help to maintain adequate nutrition. Report changes in urination or pain on urination, unresolved severe diarrhea, testicular pain, or changes in respiratory status. Pregnancy/breast-feeding precautions: Inform prescriber if you are or intend to be pregnant. Discontinue breast-feeding prior to starting this medication.


Nursing Implications

Capsule should be swallowed whole; not chewed, crushed, or opened


Dosage Forms

Capsule, delayed release: 10 mg, 20 mg, 40 mg


References

Andersson T, "Omeprazole Drug Interaction Studies," Clin Pharmacokinet, 1991, 21(3):195-212.

Balian JD, Sukhova N, Harris JW, et al, "The Hydroxylation of Omeprazole Correlates With S-Mephenytoin Metabolism: A Population Study," Clin Pharmacol Ther, 1995, 57(6):662-9.

Beutler M, Hartmann K, Kuhn M, et al, "Arthralgias on Omeprazole," BMJ, 1994, 309(6969):1620.

Carulli MT, Epstein O, and Black CM, "Small Bowel Bacterial Overgrowth and Omeprazole in Patients With Systemic Sclerosis," Br J Rheumatol, 1995, 34(Suppl 1):67.

Carvajal A and Martin Arias LH, "Gynecomastia and Sexual Disorders After the Administration of Omeprazole," Am J Gastroenterol, 1995, 90(6):1028-9.

Epelde Gonzalo FD, Boada Montagut L, and Tomas Vecina S, "Exfoliative Dermatitis Related to Omeprazole," Ann Pharmacother, 1995, 29(1):82-3.

Friedman G, "Omeprazole," Am J Gastroenterol, 1987, 82(3):188-91.

Gunasekaran TS and Hassall EG, "Efficacy and Safety of Omeprazole for Severe Gastroesophageal Reflux in Children," J Pediatr, 1993, 123(1):148-54.

Kane DL, "Administration of Omeprazole (Prilosec®) in the Atypical Patient," Int J Pharm Compounding, 1997, 1(1):13.

Kato S, Ebina K, Fujii K, et al, "Effect of Omeprazole in the Treatment of Refractory Acid-Related Diseases in Childhood: Endoscopic Healing and Twenty-Four Hour Intragastric Acidity," J Pediatr, 1996, 128(3):415-21.

Kaye SA, Lim SG, Taylor M, et al, "Small Bowel Bacterial Overgrowth in Systemic Sclerosis: Detection Using Direct and Indirect Methods and Treatment Outcome," Br J Rheumatol, 1995, 34(3):265-9.

Kraus A and Flores-Suarez LF, "Acute Gout Associated With Omeprazole," Lancet, 1995, 345(8947):461-2.

Larner AJ and Lendrum R, "Oesophageal Candidiasis After Omeprazole Therapy," Gut, 1992, 33(6):860-1.

Lindquist M and Edwards IR, "Endocrine Adverse Effects of Omeprazole," Br Med J, 1992, 305(6851):451-2.

Ottervanger JP, Stricker BH, Kappelle JW, et al, "Omeprazole-Associated Agranulocytosis," Eur J Haematol, 1995, 54(4):279-80.

Soll AH, Weinstein WM, Kurata J, et al, "Nonsteroidal Anti-inflammatory Drugs and Peptic Ulcer Disease," Ann Intern Med, 1991, 114(4):307-19.

Teare JP, Spedding C, Whitehead MW, et al, "Omeprazole and Dry Mouth," Scand J Gastroenterol, 1995, 30(3):216-8.

Woods DJ and McClintock AD, "Omeprazole Administration," Ann Pharmacother, 1993, 27(5):651.


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