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omeprazole magnesium

Heartburn Relief (UK), Losec (CA) (UK), Mepradec (UK), Prilosec, Prilosec OTC, Ratio-Omeprazole (CA), Sandoz Omeprazole (CA), Zanprol (UK)

omeprazole and sodium bicarbonate

Zegerid, Zegerid OTC

Pharmacologic class: Proton pump inhibitor

Therapeutic class: Antiulcer drug

Pregnancy risk category C


Reduces gastric acid secretion and increases gastric mucus and bicarbonate production, creating protective coating on gastric mucosa and easing discomfort from excess gastric acid


Capsules (delayed-release): 10 mg, 20 mg, 40 mg

Powder for oral suspension (delayed-release): 2.5 mg, 10 mg in packets

Tablets (delayed-release): 20 mg

Indications and dosages

Gastroesophageal reflux disease

Adults: 20 mg P.O. (capsules, powder) daily for 4 weeks

Erosive esophagitis

Adults: 20 mg P.O. (capsules, powder) daily for 4 to 8 weeks

Short-term treatment of active duodenal ulcer

Adults: 20 mg P.O. (capsules, powder) daily for 4 weeks. Some patients may need 4 additional weeks of therapy.

To reduce risk of duodenal ulcers caused by Helicobacter pylori

Adults: 40 mg P.O. (capsules) daily in morning, given with clarithromycin t.i.d. for 2 weeks; then 20 mg daily for 2 weeks

Gastric ulcers

Adults: 40 mg P.O. (capsules) daily for 4 to 8 weeks

Pathologic hypersecretory conditions, including Zollinger-Ellison syndrome

Adults: Initially, 60 mg P.O. (capsules) daily; may increase up to 120 mg t.i.d. Divide daily dosages above 80 mg.

Frequent heartburn (two or more episodes a week)

Adults ages 18 and older: 20 mg P.O. (OTC tablets, capsules, or powder) daily for 14 days

Off-label uses

• Posterior laryngitis

• To enhance pancreatin efficacy in treating steatorrhea in cystic fibrosis patients


• Hypersensitivity to drug or its components


Use cautiously in:

• hepatic disease

• hypomagnesemia

• concurrent use of clopidogrel (avoid use)

• pregnant or breastfeeding patients

• children (safety not established).


• Give 30 to 60 minutes before a meal, preferably in morning.

• If desired, give concurrently with antacids.

• Know that if patient has ulcer at start of therapy, treatment may be extended.

• When giving through nasogastric tube, use powder for oral suspension, or separate capsule and mix pellets with water. Agitate syringe while injecting. After administration, flush with 30 to 60 ml of water.

• Don't crush capsules.

• Be aware that symptomatic response doesn't rule out gastric cancer.

Adverse reactions

CNS: dizziness, headache, asthenia

GI: nausea, vomiting, diarrhea, constipation, abdominal pain

Metabolic: hypomagnesemia

Musculoskeletal: back pain; fractures of hip, wrist, spine (with long-term daily use)

Respiratory: cough, upper respiratory tract infection

Skin: rash


Drug-drug. Ampicillin, cyanocobalamin, iron salts, ketoconazole: reduced absorption of these drugs

Clarithromycin: increased omeprazole blood level

Clopidogrel: diminished antiplatelet activity

Diazepam, phenytoin, warfarin: prolonged elimination and increased effects of these drugs

Digoxin: increased digoxin absorption and blood level, possible digoxin toxicity

Drugs metabolized by CYP450 system: competitive metabolism

Methotrexate: increased methotrexate serum level

Penicillins: serious and occasionally fatal hypersensitivity reactions including anaphylaxis

Rifampin: substantially decreased omeprazole concentrations

Drug-diagnostic tests. Alanine phosphatase, alkaline aminotransferase, aspartate aminotransferase, bilirubin: increased levels

Gastrin: increased level during first 1 to 2 weeks of therapy

Serum chromogranin A: increased level may cause false-positive results in diagnostic investigations for neuroendocrine tumors

Serum magnesium: decreased level

Drug-herbs. St John's wort: substantially decreased omeprazole concentration

Patient monitoring

• Assess vital signs.

• Check for abdominal pain, emesis, diarrhea, or constipation.

• Evaluate fluid intake and output.

• Watch for elevated liver function test results (rare).

• Monitor magnesium level before starting drug and periodically thereafter in patients expected to be on long-term treatment or who take proton pump inhibitors with other drugs such as digoxin or drugs that may cause hypomagnesemia.

Patient teaching

• Tell patient to take 30 to 60 minutes before a meal, preferably in morning.

• Instruct patient to swallow capsules or tablets whole and not to chew or crush them. If he can't swallow capsule, tell him he may open it, carefully sprinkle and mix entire contents into 1 tbsp of cool applesauce, and swallow immediately with glass of water.

• Instruct patient on how to use delayed-release oral suspension: Empty contents of a 2.5-mg packet of powder into a container with 5 ml of water or 10-mg packet of powder into a container with 15 ml of water; don't use other liquids or foods. Stir and allow drug to thicken for 2 to 3 minutes. Stir well and drink within 30 minutes. If any drug remains after drinking, add more water to container, stir, and drink immediately.

• Inform patient taking OTC delayedrelease tablets for heartburn that full effect may take 1 to 4 days. Advise him not to take tablets for more than 14 days without consulting health care professional.

• Advise patient to avoid St John's wort while taking this drug.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.

• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs and tests mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


(o-mep-ra-zole) ,


(trade name),


(trade name),


(trade name)


Therapeutic: antiulcer agents
Pharmacologic: proton pump inhibitors
Pregnancy Category: C


GERD/maintenance of healing in erosive esophagitis.Duodenal ulcers (with or without anti-infectives for Helicobacter pylori).Short-term treatment of active benign gastric ulcer.Pathologic hypersecretory conditions, including Zollinger-Ellison syndrome.Reduction of risk of GI bleeding in critically ill patients.OTC: Heartburn occurring ≥twice/wk.


Binds to an enzyme on gastric parietal cells in the presence of acidic gastric pH, preventing the final transport of hydrogen ions into the gastric lumen.

Therapeutic effects

Diminished accumulation of acid in the gastric lumen with lessened gastroesophageal reflux.
Healing of duodenal ulcers.


Absorption: Rapidly absorbed following oral administration; immediate release formulation contains bicarbonate to prevent acid degradation.
Distribution: Good distribution into gastric parietal cells.
Protein Binding: 95%.
Metabolism and Excretion: Mostly metabolized by the liver via the cytochrome P450 (CYP) system (primarily CYP2C19 isoenzyme, but also the CYP3A4 isoenzyme) (the CYP2C19 enzyme system exhibits genetic polymorphism; genetic implication 15–20% of Asian patients and 3–5% of Caucasian and Black patients may be poor metabolizers and may have significantly ↑ omeprazole concentrations and an ↑ risk of adverse effects); inactive metabolites are excreted in urine (77%) and feces.
Half-life: 0.5–1 hr (↑ in liver disease to 3 hr).

Time/action profile (antisecretory effects)

PO-delayed releasewithin 1 hrwithin 2 hr72–96 hr


Contraindicated in: Hypersensitivity; Lactation: Discontinue omeprazole or discontinue breast feeding.
Use Cautiously in: Liver disease (dose ↓ may be necessary); Obstetric / Lactation / Pediatric: Safety not established in pregnant or breast-feeding women, or children <1 yr;Patients using high-doses for >1 year (↑ risk of hip, wrist, or spine fractures).

Adverse Reactions/Side Effects

Central nervous system

  • dizziness
  • drowsiness
  • fatigue
  • headache
  • weakness


  • chest pain


  • pseudomembranous colitis (life-threatening)
  • abdominal pain (most frequent)
  • acid regurgitation
  • constipation
  • diarrhea
  • flatulence
  • nausea
  • vomiting

Fluid and Electrolyte

  • hypomagnesemia (especially if treatment duration ≥3 mo)


  • itching
  • rash


  • bone fracture


  • allergic reactions


Drug-Drug interaction

Omeprazole is metabolized by the CYP450 enzyme system and may compete with other agents metabolized by this system.↓ metabolism and may ↑ effects of antifungal agents, diazepam, digoxin, flurazepam, triazolam, cyclosporine, phenytoin, saquinavir, tacrolimus, and warfarin.May ↓ absorption of drugs requiring acid pH, including ketoconazole, itraconazole, ampicillin, iron salts, and digoxin.Has been used safely with antacids.May significantly ↓ effects of atazanavir and nelfinavir (concurrent use not recommended).May ↑ risk of bleeding with warfarin (monitor INR/PT).Voriconazole may ↑ levels.May ↓ the antiplatelet effects of clopidogrel ; avoid concurrent use.May ↑ levels of cilostazol ; consider ↓ dose of cilostazol from 100 mg twice daily to 50 mg twice daily.Rifampin may ↓ levels and may ↓ response; avoid concurrent use.Hypomagnesemia ↑ risk of digoxin toxicity.May ↑ levels of tacrolimus and methotrexate.St. John's wort may ↓ levels and may ↓ response; avoid concurrent use.


Oral (Adults) GERD/erosive esophagitis—20 mg once daily. Duodenal ulcers associated with H. pylori—40 mg once daily in the morning with clarithromycin for 2 wk, then 20 mg once daily for 2 wk or 20 mg twice daily with clarithromycin 500 mg twice daily and amoxicillin 1000 mg twice daily for 10 days (if ulcer is present at beginning of therapy, continue omeprazole 20 mg daily for 18 more days); has also been used with clarithromycin and metronidazole. Gastric ulcer—40 mg once daily for 4–6 wk. Reduction of the risk of GI bleeding in critically ill patients—40 mg initially, then another 40 mg 6–8 hr later, followed by 40 mg once daily for up to 14 days. Gastric hypersecretory conditions—60 mg once daily initially; may be increased up to 120 mg 3 times daily (doses >80 mg/day should be given in divided doses); OTC—20 mg once daily for up to 14 days.
Oral (Children 1–16 yr and 5–9 kg) GERD/erosive esophagitis—5 mg once daily.
Oral (Children 1–16 yr and 10–19 kg) GERD/erosive esophagitis—10 mg once daily.
Oral (Children 1–16 yr and ≥20 kg) GERD/erosive esophagitis—20 mg once daily.

Availability (generic available)

Delayed-release capsules: 10 mg, 20 mgRx, OTC, 40 mg
Delayed-release powder for oral suspension peach-mint: 2.5 mg/packet, 10 mg/packet
In combination with: metronidazole and clarithromycin in a compliance package (Losec 1-2-3 M); with amoxicillin and clarithromycin in a compliance package (Losec 1-2-3-A) (both in Canada only); with sodium bicarbonate (Zegerid [OTC]; see combination drugs).

Nursing implications

Nursing assessment

  • Assess patient routinely for epigastric or abdominal pain and frank or occult blood in the stool, emesis, or gastric aspirate.
  • Monitor bowel function. Diarrhea, abdominal cramping, fever, and bloody stools should be reported to health care professional promptly as a sign of pseudomembranous colitis. May begin up to several weeks following cessation of therapy.
  • Lab Test Considerations: Monitor CBC with differential periodically during therapy.
    • May cause ↑ AST, ALT, alkaline phosphatase, and bilirubin.
    • May cause serum gastrin concentrations to ↑ during first 1–2 wk of therapy. Levels return to normal after discontinuation of omeprazole.
    • Monitor INR and prothrombin time in patients taking warfarin.
    • May cause hypomagnesemia. Monitor serum magnesium prior to and periodically during therapy.

Potential Nursing Diagnoses

Acute pain (Indications)


  • Do not confuse Prilosec (omeprazole) with Prozac (fluoxetine) or Pristiq (desvenlafaxine). Do not confuse omeprazole with fomepizole.
  • Oral: Administer doses before meals, preferably in the morning. Capsules should be swallowed whole; do not crush or chew. Capsules may be opened and sprinkled on cool applesauce, entire mixture should be ingested immediately and followed by a drink of water. Do not store for future use.
    • Powder for oral suspension: Administer on empty stomach, as least 1 hr before a meal. For patients with nasogastric or enteral feeding, suspend feeding for 3 hr before and 1 hr after administration. Empty packet contents into a small cup containing 1–2 tablespoons of water. Do not use other liquids or foods. If administered through a nasogastric tube, suspend in 20 mL of water. Stir well and drink immediately. Refill cup with water and drink again.
    • May be administered concurrently with antacids.

Patient/Family Teaching

  • Instruct patient to take medication as directed for the full course of therapy, even if feeling better. Take missed doses as soon as remembered but not if almost time for next dose. Do not double doses.
  • May cause occasional drowsiness or dizziness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
  • Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications.
  • Advise patient to avoid alcohol, products containing aspirin or NSAIDs, and foods that may cause an increase in GI irritation.
  • Advise patient to report onset of black, tarry stools; diarrhea; abdominal pain; or persistent headache to health care professional promptly.
  • Instruct patient to notify health care professional of onset of black, tarry stools; diarrhea; abdominal pain; or persistent headache or if fever and diarrhea develop, especially if stool contains blood, pus, or mucus. Advise patient not to treat diarrhea without consulting health care professional.
  • Advise female patient to notify health care professional if pregnancy is planned or suspected or if breast feeding.

Evaluation/Desired Outcomes

  • Decrease in abdominal pain or prevention of gastric irritation and bleeding. Healing of duodenal ulcers can be seen on x-ray examination or endoscopy.
  • Decrease in symptoms of GERD and erosive esophagitis. Therapy is continued for 4–8 wk after initial episode.
Drug Guide, © 2015 Farlex and Partners


A brand name for OMEPRAZOLE.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
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AstraZeneca hopes the court case will help it keep cheap generic versions of Losec away from the US markets.
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