(oh MEP ra zole)
- Omeprazole Magnesium
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule Delayed Release, Oral:
PriLOSEC: 10 mg, 20 mg, 40 mg
Generic: 10 mg, 20 mg, 40 mg
Capsule Delayed Release, Oral, as magnesium [strength expressed as base]:
Generic: 20 mg
Packet, Oral, as magnesium [strength expressed as base]:
PriLOSEC: 2.5 mg (30 ea); 10 mg (30 ea)
First-Omeprazole: 2 mg/mL (90 mL, 150 mL, 300 mL) [contains benzyl alcohol, fd&c red #40, saccharin sodium; strawberry flavor]
Omeprazole+Syrspend SF Alka: 2 mg/mL (120 mL, 240 mL)
Omeprazole+Syrspend SF Alka: 2 mg/mL (100 mL) [cherry flavor]
Tablet Delayed Release, Oral:
Generic: 20 mg
Tablet Delayed Release, Oral, as magnesium [strength expressed as base]:
PriLOSEC OTC: 20 mg
PriLOSEC OTC: 20 mg [contains fd&c blue #2 aluminum lake, fd&c red #40 aluminum lake, saccharin sodium]
PriLOSEC OTC: 20 mg [contains fd&c blue #2 aluminum lake, fd&c red #40 aluminum lake, saccharin sodium; wild berry flavor]
Brand Names: U.S.
- Omeprazole+Syrspend SF Alka
- PriLOSEC OTC [OTC]
- Proton Pump Inhibitor
- Substituted Benzimidazole
Proton pump inhibitor; suppresses gastric basal and stimulated acid secretion by inhibiting the parietal cell H+/K+ ATP pump
Hepatic via CYP2C19 primarily and (to a lesser extent) via 3A4 to hydroxy, desmethyl, and sulfone metabolites (all inactive); saturable first-pass effect
Urine (~77% as metabolites, very small amount as unchanged drug); feces
Onset of Action
Antisecretory: ~1 hour; Peak effect: Within 2 hours
Time to Peak
Plasma: 0.5 to 3.5 hours
Duration of Action
Up to 72 hours; 50% of maximum effect at 24 hours; after stopping treatment, secretory activity gradually returns over 3 to 5 days
0.5 to 1 hour; hepatic impairment: ~3 hours
Special Populations: Renal Function Impairment
There is slight increase in bioavailability in patients with chronic renal impairment.
Special Populations: Hepatic Function Impairment
In patients with chronic hepatic disease, bioavailability is increased to ~100%, plasma half-life is increased, and plasma clearance is decreased.
Special Populations: Elderly
The elimination rate is decreased. Bioavailability is increased.
Special Populations: Children
Children 2 to 5 years of age have lower AUCs than children 6 to 16 years and adults.
Special Populations: Race
AUC is increased approximately fourfold in Asian patients.
Use: Labeled Indications
Short-term (4 to 8 weeks) treatment of active duodenal ulcer disease or active benign gastric ulcer; treatment of heartburn and other symptoms associated with gastroesophageal reflux disease (GERD) (up to 4 weeks); short-term (4 to 8 weeks) treatment of endoscopically-diagnosed erosive esophagitis; maintenance healing of erosive esophagitis; long-term treatment of pathological hypersecretory conditions (eg, Zollinger-Ellison syndrome); as part of a multidrug regimen for H. pylori eradication to reduce the risk of duodenal ulcer recurrence
OTC labeling: Short-term treatment of frequent, uncomplicated heartburn occurring ≥2 days/week
Healing NSAID-induced ulcers; prevention of NSAID-induced ulcer; stress ulcer prophylaxis in the critically-ill
Hypersensitivity (eg, anaphylaxis, anaphylactic shock, angioedema, bronchospasm, acute interstitial nephritis, urticaria) to omeprazole, other substituted benzimidazole proton pump inhibitors, or any component of the formulation
Children 1 to 16 years: Oral: GERD or other acid-related disorders:
5 kg to <10 kg: 5 mg once daily
10 kg to <20 kg: 10 mg once daily
≥20 kg: 20 mg once daily
Active duodenal ulcer: 20 mg once daily for 4 to 8 weeks
Gastric ulcers: 40 mg once daily for 4 to 8 weeks
Symptomatic GERD (without esophageal lesions): 20 mg once daily for up to 4 weeks
Erosive esophagitis: 20 mg once daily for 4 to 8 weeks; maintenance of healing: 20 mg once daily for up to 12 months total therapy (including treatment period of 4 to 8 weeks)
Helicobacter pylori eradication: Dose varies with regimen:
Manufacturer labeling: 40 mg once daily administered with clarithromycin 500 mg 3 times daily for 14 days or 20 mg twice daily administered with amoxicillin 1000 mg and clarithromycin 500 mg twice daily for 10 days. Note: Presence of ulcer at time of therapy initiation may necessitate an additional 14 to 18 days of omeprazole 20 mg daily (monotherapy) after completion of combination therapy.
American College of Gastroenterology guidelines (Chey, 2007):
Nonpenicillin allergy: 20 mg twice daily administered with amoxicillin 1000 mg and clarithromycin 500 mg twice daily for 10 to 14 days
Penicillin allergy: 20 mg twice daily administered with clarithromycin 500 mg and metronidazole 500 mg twice daily for 10 to 14 days or 20 mg once or twice daily administered with bismuth subsalicylate 525 mg and metronidazole 250 mg plus tetracycline 500 mg 4 times daily for 10 to 14 days
Pathological hypersecretory conditions: Initial: 60 mg once daily; doses up to 120 mg 3 times daily have been administered; administer daily doses >80 mg in divided doses
NSAID-induced ulcer treatment (off-label use): 20 mg once daily for 4 to 8 weeks; Maintenance: 20 mg once daily for up to 6 months (Hawkey, 1998)
NSAID-induced ulcer prophylaxis (off-label use): 20 mg once daily for up to 6 months (Cullen, 1998)
Stress ulcer prophylaxis, ICU patients (off-label use): 40 mg once daily (Levy, 1997) or may administer 40 mg loading dose followed by 20 to 40 mg once daily (ASHP, 1999). Note: Intended for patients with associated risk factors (eg, coagulopathy, mechanical ventilation for ≥48 hours, severe sepsis); discontinue use once risk factors have resolved (Dellinger, 2013). Omeprazole 20 mg via NG tube once daily may be less effective in some critically ill populations compared to 40 mg via NG tube once daily (Balaban, 1997).
Frequent heartburn (OTC labeling): 20 mg once daily for 14 days; treatment may be repeated after 4 months if needed
Dosage adjustment in renal impairment: No dosage adjustment necessary.
Dosage adjustment in hepatic impairment: There are no dosage adjustments provided in the manufacturer’s labeling. However, based on increased bioavailability, a dosage reduction should be considered, especially for maintenance of healing of erosive esophagitis.
Granules for oral suspension: For oral administration, empty the contents of the 2.5 mg packet into 5 mL of water (10 mg packet into 15 mL of water); stir. For NG administration, add 5 mL of water into a catheter-tipped syringe, and then add the contents of a 2.5 mg packet (15 mL water for the 10 mg packet); shake. Note: Regardless of the route of administration, the suspension should be left to thicken for 2 to 3 minutes prior to administration.
Note: More palatable omeprazole (2 mg/mL) suspensions are commercially available as compounding kits (First-Omeprazole, Omeprazole+Syrspend SF Alka Cherry Kit).
A 2 mg/mL oral omeprazole solution (Simplified Omeprazole Solution) may be made with five omeprazole 20 mg delayed release capsules and 50 mL sodium bicarbonate 8.4%. Empty capsules into beaker. Add sodium bicarbonate solution. Gently stir (about 15 minutes) until a white suspension forms. Transfer to amber-colored syringe or bottle. Stable for 14 days at room temperature or for 30 days refrigerated.DiGiacinto JL, Olsen KM, Bergman KL, et al, “Stability of Suspension Formulations of Lansoprazole and Omeprazole Stored in Amber-Colored Plastic Oral Syringes,” Ann Pharmacother, 2000, 34(5):600-5. 10852086Quercia R, Fan C, Liu X, et al, “Stability of Omeprazole in an Extemporaneously Prepared Oral Liquid,” Am J Health Syst Pharm, 1997, 54(16):1833-6. 9269520Sharma V, “Comparison of 24-hour Intragastric pH Using Four Liquid Formulations of Lansoprazole and Omeprazole,” Am J Health Syst Pharm, 1999, 56(23 Suppl 4):18-21.10597120
Oral: Best if administered before breakfast.
Capsule: Should be swallowed whole; do not chew or crush. Delayed release capsule may be opened and contents added to 1 tablespoon of applesauce (use immediately after adding to applesauce); mixture should not be chewed or warmed.
Oral suspension: Following reconstitution, the suspension should be left to thicken for 2 to 3 minutes and administered within 30 minutes. If any material remains after administration, add more water, stir, and administer immediately.
Tablet: Should be swallowed whole; do not crush or chew.
Nasogastric/orogastric (NG/OG) tube administration:
Oral suspension (using packets): After removing a catheter-tip syringe plunger, add 5 mL of water to the syringe and the contents of a 2.5 mg packet (or 15 mL of water for the 10 mg packet). Immediately shake syringe and leave to thicken for 2 to 3 minutes; shake syringe again and within 30 minutes administer via NG or gastric tube (French size 6 or larger). Refill syringe with an equal amount of water, shake, and flush remaining contents through NG or gastric tube
Oral suspension (using capsules): The manufacturer of Prilosec® does not give recommendations for extemporaneous preparation of omeprazole capsules for NG/OG administration. Consider using the packets for oral suspension. If packets are unavailable, methods of preparation of capsules for NG/OG administration have been described (Balaban, 1997; Phillips, 1996). An extemporaneously prepared suspension with extended stability may also be used (DiGiacinto, 2000; Quercia, 1997; Sharma, 1999).
Should be taken on an empty stomach; best if taken before breakfast.
Capsules, tablets: Store at 15°C to 30°C (59°F to 86°F). Protect from light and moisture.
Granules for oral suspension: Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).
Powder for suspension (compounding kit): Prior to compounding, store at 15°C to 30°C (59°F to 86°F). Once compounded, the product is stable for 30 days under refrigeration [2°C to 8°C (36°F to 46°F)]; protect from light; protect from freezing.
OTC capsules: Store at 20°C to 25°C (68°F to 77°F); protect from moisture.
Amphetamine: Proton Pump Inhibitors may increase the absorption of Amphetamine. Monitor therapy
Antihepaciviral Combination Products: May decrease the serum concentration of Omeprazole. Monitor therapy
ARIPiprazole: CYP2D6 Inhibitors (Weak) may increase the serum concentration of ARIPiprazole. Management: Monitor for increased aripiprazole pharmacologic effects. Aripiprazole dose adjustments may or may not be required based on concomitant therapy and/or indication. Consult full interaction monograph for specific recommendations. Monitor therapy
Atazanavir: Proton Pump Inhibitors may decrease the serum concentration of Atazanavir. Management: See full drug interaction monograph for details. Consider therapy modification
Bisphosphonate Derivatives: Proton Pump Inhibitors may diminish the therapeutic effect of Bisphosphonate Derivatives. Monitor therapy
Bosentan: CYP2C9 Inhibitors (Moderate) may increase the serum concentration of Bosentan. Management: Concomitant use of both a CYP2C9 inhibitor and a CYP3A inhibitor or a single agent that inhibits both enzymes with bosentan is likely to cause a large increase in serum concentrations of bosentan and is not recommended. See monograph for details. Monitor therapy
Bosutinib: Proton Pump Inhibitors may decrease the serum concentration of Bosutinib. Management: Consider alternatives to proton pump inhibitors, such as antacids or H2 receptor antagonists. Administer alternative agents more than 2 hours before or after bosutinib. Consider therapy modification
Cannabis: CYP2C9 Inhibitors (Moderate) may increase the serum concentration of Cannabis. More specifically, tetrahydrocannabinol serum concentrations may be increased. Monitor therapy
Carvedilol: CYP2C9 Inhibitors (Moderate) may increase the serum concentration of Carvedilol. Specifically, concentrations of the S-carvedilol enantiomer may be increased. Monitor therapy
Cefditoren: Proton Pump Inhibitors may decrease the serum concentration of Cefditoren. Management: If possible, avoid use of cefditoren with proton pump inhibitors (PPIs). Consider alternative methods to minimize/control acid reflux (eg, diet modification) or alternative antimicrobial therapy if use of PPIs can not be avoided. Consider therapy modification
Cilostazol: CYP2C19 Inhibitors may increase the serum concentration of Cilostazol. Management: Consider reducing the cilostazol dose to 50 mg twice daily in patients who are also receiving inhibitors of CYP2C19. Consider therapy modification
Citalopram: CYP2C19 Inhibitors (Moderate) may increase the serum concentration of Citalopram. Management: Limit citalopram dose to a maximum of 20 mg/day if used with a moderate CYP2C19 inhibitor. Patients using this combination should be monitored closely for evidence of citalopram toxicity (e.g., serotonin syndrome, QT prolongation, etc.). Consider therapy modification
Clopidogrel: Omeprazole may diminish the antiplatelet effect of Clopidogrel. Omeprazole may decrease serum concentrations of the active metabolite(s) of Clopidogrel. Avoid combination
CloZAPine: Omeprazole may decrease the serum concentration of CloZAPine. Omeprazole may increase the serum concentration of CloZAPine. Monitor therapy
CycloSPORINE (Systemic): Omeprazole may increase the serum concentration of CycloSPORINE (Systemic). Monitor therapy
CYP2C19 Inducers (Strong): May increase the metabolism of CYP2C19 Substrates. Management: Consider an alternative for one of the interacting drugs. Some combinations may be specifically contraindicated. Consult appropriate manufacturer labeling. Consider therapy modification
CYP2C19 Substrates: CYP2C19 Inhibitors (Moderate) may decrease the metabolism of CYP2C19 Substrates. Monitor therapy
CYP2C9 Substrates: CYP2C9 Inhibitors (Moderate) may decrease the metabolism of CYP2C9 Substrates. Monitor therapy
Cysteamine (Systemic): Proton Pump Inhibitors may diminish the therapeutic effect of Cysteamine (Systemic). Monitor therapy
Dabigatran Etexilate: Proton Pump Inhibitors may decrease serum concentrations of the active metabolite(s) of Dabigatran Etexilate. Monitor therapy
Dabrafenib: May decrease the serum concentration of CYP2C19 Substrates. Management: Seek alternatives to the CYP2C19 substrate when possible. If concomitant therapy cannot be avoided, monitor clinical effects of the substrate closely (particularly therapeutic effects). Consider therapy modification
Dabrafenib: Proton Pump Inhibitors may decrease the serum concentration of Dabrafenib. Dabrafenib may decrease the serum concentration of Proton Pump Inhibitors. Management: Seek alternatives to the proton pump inhibitor when possible. If concomitant therapy cannot be avoided, monitor for diminished effects of both drugs. Consider therapy modification
Dasatinib: Proton Pump Inhibitors may decrease the serum concentration of Dasatinib. Management: Antacids (taken 2 hours before or after dasatinib administration) can be used in place of the proton pump inhibitor if some acid-reducing therapy is needed. Avoid combination
Delavirdine: Proton Pump Inhibitors may decrease the serum concentration of Delavirdine. Management: Chronic therapy with proton pump inhibitors (PPIs) should be avoided in patients treated with delavirdine. The clinical significance of short-term PPI therapy with delavirdine is uncertain, but such therapy should be undertaken with caution. Avoid combination
Dexmethylphenidate: Proton Pump Inhibitors may increase the absorption of Dexmethylphenidate. Specifically, proton pump inhibitors may interfere with the normal release of drug from the extended-release capsules (Focalin XR brand), which could result in both increased absorption (early) and decreased delayed absorption. Monitor therapy
Dextroamphetamine: Proton Pump Inhibitors may increase the absorption of Dextroamphetamine. Specifically, the dextroamphetamine absorption rate from mixed amphetamine salt extended release (XR) capsules may be increased in the first hours after dosing. Monitor therapy
Dronabinol: CYP2C9 Inhibitors (Moderate) may increase the serum concentration of Dronabinol. Monitor therapy
Enzalutamide: May decrease the serum concentration of CYP2C19 Substrates. Conversely, concentrations of active metabolites may be increased for those drugs activated by CYP2C19. Management: Concurrent use of enzalutamide with CYP2C19 substrates that have a narrow therapeutic index should be avoided. Use of enzalutamide and any other CYP2C19 substrate should be performed with caution and close monitoring. Consider therapy modification
Erlotinib: Proton Pump Inhibitors may decrease the serum concentration of Erlotinib. Avoid combination
Escitalopram: Omeprazole may increase the serum concentration of Escitalopram. Management: Monitor for increased escitalopram toxicity with concomitant use of omeprazole. Recommendations for management of this interaction found in product labeling may differ by country. Consult appropriate labeling. Consider therapy modification
Fluconazole: May increase the serum concentration of Proton Pump Inhibitors. Monitor therapy
Fosphenytoin: Omeprazole may increase the serum concentration of Fosphenytoin. Fosphenytoin may decrease the serum concentration of Omeprazole. Monitor therapy
Gefitinib: Proton Pump Inhibitors may decrease the serum concentration of Gefitinib. Management: Avoid use of proton pump inhibitors (PPIs) with gefitinib when possible. If required, administer gefitinib 12 hours after administration of the PPI or 12 hours before the next dose of the PPI. Consider therapy modification
Indinavir: Proton Pump Inhibitors may decrease the serum concentration of Indinavir. Monitor therapy
Iron Salts: Proton Pump Inhibitors may decrease the absorption of Iron Salts. Exceptions: Ferric Carboxymaltose; Ferric Citrate; Ferric Gluconate; Ferric Pyrophosphate Citrate; Ferumoxytol; Iron Dextran Complex; Iron Sucrose. Monitor therapy
Itraconazole: Proton Pump Inhibitors may decrease the serum concentration of Itraconazole. Consider therapy modification
Ketoconazole (Systemic): Proton Pump Inhibitors may decrease the serum concentration of Ketoconazole (Systemic). Ketoconazole (Systemic) may increase the serum concentration of Proton Pump Inhibitors. Consider therapy modification
Ledipasvir: Proton Pump Inhibitors may decrease the serum concentration of Ledipasvir. Management: Avoid the use of PPIs at doses greater than the equivalent of omeprazole 20 mg, avoid administration of PPIs within 2 hours prior to ledipasvir dosing, and avoid use of PPIs in combination with food. Consider therapy modification
Lumacaftor: May decrease the serum concentration of CYP2C19 Substrates. Monitor therapy
Mesalamine: Proton Pump Inhibitors may diminish the therapeutic effect of Mesalamine. Proton pump inhibitor-mediated increases in gastrointestinal pH may cause the premature release of mesalamine from specific sustained-release mesalamine products. Management: Consider avoiding concurrent administration of high-dose proton pump inhibitors (PPIs) with sustained-release mesalamine products. Consider therapy modification
Methotrexate: Proton Pump Inhibitors may increase the serum concentration of Methotrexate. Monitor therapy
Methylphenidate: Proton Pump Inhibitors may increase the absorption of Methylphenidate. Specifically, proton pump inhibitors may interfere with the normal release of drug from the extended-release capsules (Ritalin LA brand), which could result in both increased absorption (early) and decreased delayed absorption. Monitor therapy
Multivitamins/Minerals (with ADEK, Folate, Iron): Proton Pump Inhibitors may decrease the serum concentration of Multivitamins/Minerals (with ADEK, Folate, Iron). Specifically, the absorption of iron may be decreased. Monitor therapy
Mycophenolate: Proton Pump Inhibitors may decrease the serum concentration of Mycophenolate. Specifically, concentrations of the active mycophenolic acid may be reduced. Monitor therapy
Nelfinavir: Proton Pump Inhibitors may decrease serum concentrations of the active metabolite(s) of Nelfinavir. Proton Pump Inhibitors may decrease the serum concentration of Nelfinavir. Avoid combination
Nilotinib: Proton Pump Inhibitors may decrease the serum concentration of Nilotinib. Management: Avoid this combination when possible since separation of doses is not likely to be an adequate method of minimizing the interaction. Consider therapy modification
PAZOPanib: Proton Pump Inhibitors may decrease the serum concentration of PAZOPanib. Avoid combination
Phenytoin: May decrease the serum concentration of Omeprazole. Omeprazole may increase the serum concentration of Phenytoin. Monitor therapy
Posaconazole: Proton Pump Inhibitors may decrease the serum concentration of Posaconazole. Consider therapy modification
Raltegravir: Proton Pump Inhibitors may increase the serum concentration of Raltegravir. Monitor therapy
Rifampin: May decrease the serum concentration of Omeprazole. Avoid combination
Rilpivirine: Proton Pump Inhibitors may decrease the serum concentration of Rilpivirine. Avoid combination
Riociguat: Proton Pump Inhibitors may decrease the serum concentration of Riociguat. Monitor therapy
Risedronate: Proton Pump Inhibitors may diminish the therapeutic effect of Risedronate. Proton Pump Inhibitors may increase the serum concentration of Risedronate. This applies specifically to use of delayed-release risedronate. Avoid combination
Saquinavir: Proton Pump Inhibitors may increase the serum concentration of Saquinavir. Monitor therapy
St Johns Wort: May decrease the serum concentration of Omeprazole. Avoid combination
Tacrolimus (Systemic): Proton Pump Inhibitors may increase the serum concentration of Tacrolimus (Systemic). Management: Tacrolimus dose adjustment may be required. Rabeprazole, pantoprazole, or selected H2-receptor antagonists (i.e., ranitidine or famotidine) may be less likely to interact. Genetic testing may predict patients at highest risk. Consider therapy modification
Tetrahydrocannabinol: CYP2C9 Inhibitors (Moderate) may increase the serum concentration of Tetrahydrocannabinol. Monitor therapy
Tipranavir: May decrease the serum concentration of Proton Pump Inhibitors. These data are derived from studies with Ritonavir-boosted Tipranavir. Monitor therapy
TiZANidine: CYP1A2 Inhibitors (Weak) may increase the serum concentration of TiZANidine. Management: Avoid these combinations when possible. If combined use cannot be avoided, initiate tizanidine at an adult dose of 2 mg and increase in 2-4 mg increments based on patient response. Monitor for increased effects of tizanidine, including adverse reactions. Consider therapy modification
Vitamin K Antagonists (eg, warfarin): Omeprazole may increase the serum concentration of Vitamin K Antagonists. Monitor therapy
Voriconazole: May increase the serum concentration of Proton Pump Inhibitors. Proton Pump Inhibitors may increase the serum concentration of Voriconazole. Management: In patients receiving omeprazole 40 mg/day or greater, reduce omeprazole dose by half when initiating voriconazole. Monitor therapy
Omeprazole may falsely elevate serum chromogranin A (CgA) levels. The increased CgA level may cause false-positive results in the diagnosis of a neuroendocrine tumor. Temporarily stop omeprazole ≥14 days prior to assessing CgA level; repeat level if initially elevated; use the same laboratory for all testing of CgA levels.
1% to 10%:
Central nervous system: Headache (7%), dizziness (2%)
Dermatologic: Skin rash (2%)
Gastrointestinal: Abdominal pain (5%), diarrhea (4%), nausea (4%), flatulence (3%), vomiting (3%), acid regurgitation (2%), constipation (2%)
Neuromuscular & skeletal: Back pain (1%), weakness (1%)
Respiratory: Upper respiratory infection (2%), cough (1%)
<1% (Limited to important or life-threatening; adverse event occurrence may vary based on formulation): Abdominal swelling, abnormal dreams, aggression, agranulocytosis, allergic reactions, alopecia, anaphylaxis, anemia, angina pectoris, angioedema, anorexia, apathy, arthralgia, atrophic gastritis, benign gastric polyps, blurred vision, bone fracture, bradycardia, bronchospasm, chest pain, cholestatic hepatitis, chronic renal disease (Lazarus 2016), Clostridium difficile-associated diarrhea (CDAD), confusion, depression, dermatitis, diplopia, drowsiness, epistaxis, erythema multiforme, esophageal candidiasis, fecal discoloration, gastroduodenal carcinoids, glycosuria, gynecomastia, hallucinations, hematuria, hemolytic anemia, hepatic disease (hepatocellular, cholestatic, mixed), hepatic encephalopathy, hepatic failure, hepatic necrosis, hepatitis, hepatocellular hepatitis, hepatotoxicity (idiosyncratic) (Chalasani 2014), hyperhidrosis, hypersensitivity, hypertension, hypocalcemia, hypoglycemia, hypokalemia, hypomagnesemia, hyponatremia, increased gamma glutamyl transferase, increased serum alkaline phosphatase, increased serum bilirubin, increased serum creatinine, increased serum transaminases, insomnia, interstitial nephritis, irritable bowel syndrome, jaundice, leg pain, leukocytosis, leukopenia, malaise, microscopic colitis, microscopic pyuria, mucosal atrophy (tongue), muscle cramps, myalgia, myasthenia, nervousness, neutropenia, ocular irritation, optic atrophy, optic neuritis, optic neuropathy (anterior ischemic), osteoporosis-related fracture, pain, palpitation, pancreatitis, pancytopenia, paresthesia, peripheral edema, petechiae, photophobia, pneumonia, proteinuria, pruritus, psychiatric disturbance, purpura, sleep disturbance, sore throat, Stevens-Johnson syndrome, stomatitis, tachycardia, testicular pain, thrombocytopenia, toxic epidermal necrolysis, tremor, urinary tract infection, urticaria, weight gain, xeroderma, xerophthalmia, xerostomia
Concerns related to adverse effects:
• Atrophic gastritis: Long-term omeprazole therapy has caused atrophic gastritis (identified by biopsy).
• Carcinoma: 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.
• Clostridium difficile-associated diarrhea (CDAD): Use of proton pump inhibitors (PPIs) may increase risk of CDAD, especially in hospitalized patients; consider CDAD diagnosis in patients with persistent diarrhea that does not improve. Use the lowest dose and shortest duration of PPI therapy appropriate for the condition being treated.
• Fractures: Increased incidence of osteoporosis-related bone fractures of the hip, spine, or wrist may occur with proton pump inhibitor (PPI) therapy. Patients on high-dose (multiple daily doses) or long-term (≥1 year) therapy should be monitored. Use the lowest effective dose for the shortest duration of time, use vitamin D and calcium supplementation, and follow appropriate guidelines to reduce risk of fractures in patients at risk.
• Hypomagnesemia: Reported rarely, usually with prolonged PPI use of >3 months (most cases >1 year of therapy). May be symptomatic or asymptomatic; severe cases may cause tetany, seizures, and cardiac arrhythmias. Consider obtaining serum magnesium concentrations prior to beginning long-term therapy, especially if taking concomitant digoxin, diuretics, or other drugs known to cause hypomagnesemia; and periodically thereafter. Hypomagnesemia may be corrected by magnesium supplementation, although discontinuation of omeprazole may be necessary; magnesium levels typically return to normal within 1 week of stopping.
• Interstitial nephritis: Acute interstitial nephritis has been observed in patients taking PPIs; may occur at any time during therapy and is generally due to an idiopathic hypersensitivity reaction. Discontinue if acute interstitial nephritis develops.
• Vitamin B12 deficiency: Prolonged treatment (≥2 years) may lead to vitamin B12 malabsorption and subsequent vitamin B12 deficiency. The magnitude of the deficiency is dose-related and the association is stronger in females and those younger in age (<30 years); prevalence is decreased after discontinuation of therapy (Lam, 2013).
• Gastric malignancy: Relief of symptoms does not preclude the presence of a gastric malignancy.
• Gastrointestinal infection (eg, Salmonella, Campylobacter): Use of PPIs may increase risk of these infections.
• Hepatic impairment: Bioavailability may be increased in patients with hepatic dysfunction; consider dosage reductions, especially for maintenance healing of erosive esophagitis.
Concurrent drug therapy issues:
• Clopidogrel: Proton pump inhibitors (PPIs) may diminish the therapeutic effect of clopidogrel, thought to be due to reduced formation of the active metabolite of clopidogrel. The manufacturer of clopidogrel recommends either avoidance of both omeprazole (even when scheduled 12 hours apart) and esomeprazole or use of a PPI with comparatively less effect on the active metabolite of clopidogrel (eg, pantoprazole). In contrast to these warnings, others have recommended the continued use of PPIs, regardless of the degree of inhibition, in patients with a history of GI bleeding or multiple risk factors for GI bleeding who are also receiving clopidogrel since no evidence has established clinically meaningful differences in outcome; however, a clinically significant interaction cannot be excluded in those who are poor metabolizers of clopidogrel (Abraham, 2010; Levine, 2011).
• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.
• Asian ethnicity: Bioavailability may be increased in patients of Asian descent; consider dosage reductions, especially for maintenance healing of erosive esophagitis.
• Elderly: Bioavailability may be increased in the elderly.
Dosage form specific issues:
• Benzyl alcohol and derivatives: Some dosage forms may contain benzyl alcohol; large amounts of benzyl alcohol (≥99 mg/kg/day) have been associated with a potentially fatal toxicity (“gasping syndrome”) in neonates; the “gasping syndrome” consists of metabolic acidosis, respiratory distress, gasping respirations, CNS dysfunction (including convulsions, intracranial hemorrhage), hypotension, and cardiovascular collapse (AAP ["Inactive" 1997]; CDC, 1982); some data suggests that benzoate displaces bilirubin from protein binding sites (Ahlfors, 2001); avoid or use dosage forms containing benzyl alcohol with caution in neonates. See manufacturer’s labeling.
• Appropriate use: Helicobacter pylori eradication: Short-term combination therapy (≤7 days) has been associated with a higher incidence of treatment failure. The American College of Gastroenterology recommends 10 to 14 days of therapy (triple or quadruple) for eradication of H. pylori (Chey, 2007).
• Self-medication (OTC use): When used for self-medication (OTC), do not use for >14 days; treatment should not be repeated more often than every 4 months.
Susceptibility testing is recommended in patients who fail H. pylori-eradication regimen.
Pregnancy Risk Factor
Adverse events have been observed in some animal reproduction studies. An increased risk of hypospadias was reported following maternal use of proton pump inhibitors (PPIs) during pregnancy (Anderka, 2012), but this was based on a small number of exposures and the same association was not found in another study (Erichsen, 2012). Most available studies have not shown an increased risk of major birth defects following maternal use of omeprazole during pregnancy (Diav-Citrin, 2005; Källén, 2001; Lalkin, 1998; Matok, 2012; Pasternak, 2010). When treating GERD in pregnancy, PPIs may be used when clinically indicated (Katz, 2013).
• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
• Patient may experience headache, nausea, or flatulence. Have patient report immediately to prescriber signs of hypomagnesemia, severe dizziness, syncope, considerable dyspepsia, osteodynia, chills, pharyngitis, excessive weight loss, significant diarrhea, melena, or signs of Stevens-Johnson syndrome/toxic epidermal necrolysis (HCAHPS).
• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.
Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.
More about omeprazole
- Other brands: Prilosec