Prilosec Side Effects Center

Last updated on RxList: 3/22/2022
Prilosec Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

What Is Prilosec?

Prilosec (omeprazole) is a proton pump inhibitor (PPI) used for the treatment of conditions such as ulcers, gastroesophageal reflux disease (GERD), and Zollinger-Ellison syndrome, which are all caused by stomach acid. Prilosec is available in generic form.

What Are Side Effects of Prilosec?

Side effects of Prilosec include:

Dosage for Prilosec

The recommended adult oral dose of Prilosec ranges from 20 mg to 60 mg once daily, depending on the condition being treated. For maximal efficacy, Prilosec tablets should be taken before meals, swallowed whole and should not be crushed, chewed or opened.

What Drugs, Substances, or Supplements Interact with Prilosec?

Prilosec potentially can increase the concentrations in blood of diazepam (Valium), warfarin (Coumadin), and phenytoin (Dilantin) by decreasing the elimination of these drugs by the liver. The absorption of certain drugs may be affected by stomach acidity, and, as a result, Prilosec and other PPIs that reduce stomach acid also reduce the absorption and concentration in blood of ketoconazole (Nizoral) and increase the absorption and concentration in blood of digoxin (Lanoxin).

Prilosec During Pregnancy and Breastfeeding

Tell your doctor if you are pregnant or plan to become pregnant while using Prilosec; it is unknown if it will harm a fetus. Prilosec passes into breast milk and may harm a nursing baby. Breastfeeding while taking Prilosec is not recommended.

Additional Information

Our Prilosec Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

SLIDESHOW

Digestive Disorders: Common Misconceptions See Slideshow
Prilosec Consumer Information

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Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using omeprazole and call your doctor at once if you have:

  • severe stomach pain, diarrhea that is watery or bloody;
  • new or unusual pain in your wrist, thigh, hip, or back;
  • seizure (convulsions);
  • kidney problems--fever, rash, nausea, loss of appetite, joint pain, urinating less than usual, blood in your urine, weight gain;
  • low magnesium--dizziness, irregular heartbeats, feeling jittery, muscle cramps, muscle spasms, cough or choking feeling; or
  • new or worsening symptoms of lupus--joint pain, and a skin rash on your cheeks or arms that worsens in sunlight.

Taking omeprazole long-term may cause you to develop stomach growths called fundic gland polyps. Talk with your doctor about this risk.

If you use omeprazole for longer than 3 years, you could develop a vitamin B-12 deficiency. Talk to your doctor about how to manage this condition if you develop it.

Common side effects may include:

  • cold symptoms such as stuffy nose, sneezing, sore throat (especially in children);
  • fever (especially in children);
  • stomach pain, gas;
  • nausea, vomiting, diarrhea; or
  • headache.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Prilosec (Omeprazole)

Prilosec Professional Information

SIDE EFFECTS

The following serious adverse reactions are described below and elsewhere in labeling:

  • Acute Tubulointerstitial Nephritis [see WARNINGS AND PRECAUTIONS]
  • Clostridium difficile-Associated Diarrhea [see WARNINGS AND PRECAUTIONS]
  • Bone Fracture [see WARNINGS AND PRECAUTIONS]
  • Severe Cutaneous Adverse Reactions [see WARNINGS AND PRECAUTIONS]
  • Cutaneous and Systemic Lupus Erythematosus [see WARNINGS AND PRECAUTIONS]
  • Cyanocobalamin (Vitamin B-12) Deficiency [see WARNINGS AND PRECAUTIONS]
  • Hypomagnesemia and Mineral Metabolism [see WARNINGS AND PRECAUTIONS]
  • Fundic Gland Polyps [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience With PRILOSEC

Monotherapy

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The safety data described below reflects exposure to omeprazole magnesium delayed-release capsules in 3096 patients from worldwide clinical trials (465 patients from US studies and 2631 patients from international studies). Indications clinically studied in US trials included duodenal ulcer, resistant ulcer, and Zollinger-Ellison syndrome. The international clinical trials were double blind and open-label in design. The most common adverse reactions reported (i.e., with an incidence rate ≥2%) from PRILOSEC-treated patients enrolled in these studies included headache (7%), abdominal pain (5%), nausea (4%), diarrhea (4%), vomiting (3%), and flatulence (3%).

Additional adverse reactions that were reported with an incidence ≥1% included acid regurgitation (2%), upper respiratory infection (2%), constipation (2%), dizziness (2%), rash (2%), asthenia (1%), back pain (1%), and cough (1%).

The clinical trial safety profile in patients greater than 65 years of age was similar to that in patients 65 years of age or less.

The clinical trial safety profile in pediatric patients who received omeprazole magnesium delayed-release capsules was similar to that in adult patients. Unique to the pediatric population, however, adverse reactions of the respiratory system were frequently reported in the 1 month to <1 year age group, the 1 to <2 year age group, and the 2 to 16 year age group (42%, 75%, and 19%, respectively). In addition, otitis media was frequently reported in the 1 month to <1 year age group (22%), fever was frequently reported in the 1 to <2 year age group (33%), and accidental injuries were frequently reported in the 2 to 16 year age group (4%) [see Use In Specific Populations].

Clinical Trials Experience With PRILOSEC In Combination Therapy For H. pylori Eradication

In clinical trials using either dual therapy with omeprazole magnesium delayed-release capsules and clarithromycin, or triple therapy with omeprazole magnesium delayed-release capsules, clarithromycin, and amoxicillin, no adverse reactions unique to these drug combinations were observed. Adverse reactions observed were limited to those previously reported with omeprazole, clarithromycin, or amoxicillin alone.

Dual Therapy (omeprazole magnesium delayed-release capsules/clarithromycin)

Adverse reactions observed in controlled clinical trials using combination therapy with omeprazole magnesium delayed-release capsules and clarithromycin (n = 346) that differed from those previously described for omeprazole magnesium delayed-release capsules alone were taste perversion (15%), tongue discoloration (2%), rhinitis (2%), pharyngitis (1%) and flu-syndrome (1%). (For more information on clarithromycin, refer to the clarithromycin prescribing information, Adverse Reactions section.)

Triple Therapy (omeprazole magnesium delayed-release capsules/clarithromycin/amoxicillin)

The most frequent adverse reactions observed in clinical trials using combination therapy with omeprazole magnesium delayed-release capsules, clarithromycin, and amoxicillin (n = 274) were diarrhea (14%), taste perversion (10%), and headache (7%). None of these occurred at a higher frequency than that reported by patients taking antimicrobial agents alone. (For more information on clarithromycin or amoxicillin, refer to the respective prescribing information, Adverse Reactions sections.)

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of omeprazole. Because these reactions are voluntarily reported from a population of uncertain size, it is not always possible to reliably estimate their actual frequency or establish a causal relationship to drug exposure.

Body As a Whole: Hypersensitivity reactions including anaphylaxis, anaphylactic shock, angioedema, bronchospasm, interstitial nephritis, urticaria, (see also Skin below); fever; pain; fatigue; malaise; systemic lupus erythematosus

Cardiovascular: Chest pain or angina, tachycardia, bradycardia, palpitations, elevated blood pressure, peripheral edema

Endocrine: Gynecomastia

Gastrointestinal: Pancreatitis (some fatal), anorexia, irritable colon, fecal discoloration, esophageal candidiasis, mucosal atrophy of the tongue, stomatitis, abdominal swelling, dry mouth, microscopic colitis, fundic gland polyps.

Gastroduodenal carcinoids have been reported in patients with ZE syndrome on long-term treatment with omeprazole. This finding is believed to be a manifestation of the underlying condition, which is known to be associated with such tumors.

Hepatic: Liver disease including hepatic failure (some fatal), liver necrosis (some fatal), hepatic encephalopathy hepatocellular disease, cholestatic disease, mixed hepatitis, jaundice, and elevations of liver function tests [ALT, AST, GGT, alkaline phosphatase, and bilirubin]

Infections and Infestations: Clostridium difficile-associated diarrhea

Metabolism and Nutritional disorders: Hypomagnesemia, hypocalcemia, hypokalemia [Warnings and Precautions 5.9], hyponatremia, hypoglycemia, weight gain

Musculoskeletal: Muscle weakness, myalgia, muscle cramps, joint pain, leg pain, bone fracture

Nervous System/Psychiatric: Psychiatric and sleep disturbances including depression, agitation, aggression, hallucinations, confusion, insomnia, nervousness, apathy, somnolence, anxiety, and dream abnormalities; tremors, paresthesia; vertigo

Respiratory: Epistaxis, pharyngeal pain

Skin: Severe generalized skin reactions including toxic SJS/TEN (some fatal), DRESS, AGEP, cutaneous lupus erythematosus and erythema multiforme; photosensitivity; urticaria; rash; skin inflammation; pruritus; petechiae; purpura; alopecia; dry skin; hyperhidrosis

Special Senses: Tinnitus, taste perversion

Ocular: Optic atrophy, anterior ischemic optic neuropathy, optic neuritis, dry eye syndrome, ocular irritation, blurred vision, double vision

Urogenital: Interstitial nephritis, hematuria, proteinuria, elevated serum creatinine, microscopic pyuria, urinary tract infection, glycosuria, urinary frequency, testicular pain

Hematologic: Agranulocytosis (some fatal), hemolytic anemia, pancytopenia, neutropenia, anemia, thrombocytopenia, leukopenia, leukocytosis

DRUG INTERACTIONS

Tables 3 and 4 include drugs with clinically important drug interactions and interaction with diagnostics when administered concomitantly with omeprazole and instructions for preventing or managing them.

Consult the labeling of concomitantly used drugs to obtain further information about interactions with PPIs.

Table 3: Clinically Relevant Interactions Affecting Drugs Co-Administered with Omeprazole and Interaction with Diagnostics

Antiretrovirals
Clinical Impact: The effect of PPIs on antiretroviral drugs is variable. The clinical importance and the mechanisms behind these interactions are not always known.
  • Decreased exposure of some antiretroviral drugs (e.g., rilpivirine, atazanavir and nelfinavir) when used concomitantly with omeprazole may reduce antiviral effect and promote the development of drug resistance [see CLINICAL PHARMACOLOGY].
  • Increased exposure of other antiretroviral drugs (e.g., saquinavir) when used concomitantly with omeprazole may increase toxicity [see CLINICAL PHARMACOLOGY].
  • There are other antiretroviral drugs which do not result in clinically relevant interactions with omeprazole.
Intervention: Rilpivirine-containing products: Concomitant use with PRILOSEC is contraindicated [see CONTRAINDICATIONS].
Atazanavir: Avoid concomitant use with PRILOSEC. See prescribing information for atazanavir for dosing information.
Nelfinavir: Avoid concomitant use with PRILOSEC. See prescribing information for nelfinavir.
Saquinavir: See the prescribing information for saquinavir for monitoring of potential saquinavir-related toxicities.
Other antiretrovirals: See prescribing information for specific antiretroviral drugs.
Warfarin
Clinical Impact: Increased INR and prothrombin time in patients receiving PPIs, including omeprazole, and warfarin concomitantly. Increases in INR and prothrombin time may lead to abnormal bleeding and even death.
Intervention: Monitor INR and prothrombin time and adjust the dose of warfarin, if needed, to maintain target INR range.
Methotrexate
Clinical Impact: Concomitant use of omeprazole with methotrexate (primarily at high dose) may elevate and prolong serum concentrations of methotrexate and/or its metabolite hydroxymethotrexate, possibly leading to methotrexate toxicities. No formal drug interaction studies of high-dose methotrexate with PPIs have been conducted [see WARNINGS AND PRECAUTIONS].
Intervention: A temporary withdrawal of PRILOSEC may be considered in some patients receiving high-dose methotrexate.
CYP2C19 Substrates (e.g., clopidogrel, citalopram, cilostazol, phenytoin, diazepam)
Clopidogrel
Clinical Impact: Concomitant use of omeprazole 80 mg results in reduced plasma concentrations of the active metabolite of clopidogrel and a reduction in platelet inhibition [see CLINICAL PHARMACOLOGY]. There are no adequate combination studies of a lower dose of omeprazole or a higher dose of clopidogrel in comparison with the approved dose of clopidogrel.
Intervention: Avoid concomitant use with PRILOSEC. Consider use of alternative anti-platelet therapy [see WARNINGS AND PRECAUTIONS].
Citalopram
Clinical Impact: Increased exposure of citalopram leading to an increased risk of QT prolongation [see CLINICAL PHARMACOLOGY].
Intervention: Limit the dose of citalopram to a maximum of 20 mg per day. See prescribing information for citalopram.
Cilostazol
Clinical Impact: Increased exposure of one of the active metabolites of cilostazol (3,4-dihydro-cilostazol) [see CLINICAL PHARMACOLOGY].
Intervention: Reduce the dose of cilostazol to 50 mg twice daily. See prescribing information for cilostazol.
Phenytoin
Clinical Impact: Potential for increased exposure of phenytoin.
Intervention: Monitor phenytoin serum concentrations. Dose adjustment may be needed to maintain therapeutic drug concentrations. See prescribing information for phenytoin.
Diazepam
Clinical Impact: Increased exposure of diazepam [see CLINICAL PHARMACOLOGY].
Intervention: Monitor patients for increased sedation and reduce the dose of diazepam as needed.
Digoxin
Clinical Impact: Potential for increased exposure of digoxin [see CLINICAL PHARMACOLOGY].
Intervention: Monitor digoxin concentrations. Dose adjustment may be needed to maintain therapeutic drug concentrations. See digoxin prescribing information.
Drugs Dependent on Gastric pH for Absorption (e.g., iron salts, erlotinib, dasatinib, nilotinib, mycophenolate mofetil, ketoconazole/itraconazole)
Clinical Impact: Omeprazole can reduce the absorption of other drugs due to its effect on reducing intragastric acidity.
Intervention: Mycophenolate mofetil (MMF): Co-administration of omeprazole in healthy subjects and in transplant patients receiving MMF has been reported to reduce the exposure to the active metabolite, mycophenolic acid (MPA), possibly due to a decrease in MMF solubility at an increased gastric pH. The clinical relevance of reduced MPA exposure on organ rejection has not been established in transplant patients receiving PRILOSEC and MMF. Use PRILOSEC with caution in transplant patients receiving MMF [see CLINICAL PHARMACOLOGY].
See the prescribing information for other drugs dependent on gastric pH for absorption.
Combination Therapy with Clarithromycin and Amoxicillin
Clinical Impact: Concomitant administration of clarithromycin with other drugs can lead to serious adverse reactions, including potentially fatal arrhythmias, and are contraindicated.
Amoxicillin also has drug interactions.
Intervention: See Contraindications, Warnings and Precautions in prescribing information for clarithromycin.
See Drug Interactions in prescribing information for amoxicillin.
Tacrolimus
Clinical Impact: Potential for increased exposure of tacrolimus, especially in transplant patients who are intermediate or poor metabolizers of CYP2C19.
Intervention: Monitor tacrolimus whole blood concentrations. Dose adjustment may be needed to maintain therapeutic drug concentrations. See prescribing information for tacrolimus.
Interactions with Investigations of Neuroendocrine Tumors
Clinical Impact: Serum chromogranin A (CgA) levels increase secondary to PPI-induced decreases in gastric acidity. The increased CgA level may cause false positive results in diagnostic investigations for neuroendocrine tumors [see WARNINGS AND PRECAUTIONS, CLINICAL PHARMACOLOGY].
Intervention: Temporarily stop PRILOSEC treatment at least 14 days before assessing CgA levels and consider repeating the test if initial CgA levels are high. If serial tests are performed (e.g., for monitoring), the same commercial laboratory should be used for testing, as reference ranges between tests may vary.
Interaction with Secretin Stimulation Test
Clinical Impact: Hyper-response in gastrin secretion in response to secretin stimulation test, falsely suggesting gastrinoma.
Intervention: Temporarily stop PRILOSEC treatment at least 14 days before assessing to allow gastrin levels to return to baseline [see CLINICAL PHARMACOLOGY].
False Positive Urine Tests for THC
Clinical Impact: There have been reports of false positive urine screening tests for tetrahydrocannabinol (THC) in patients receiving PPIs.
Intervention: An alternative confirmatory method should be considered to verify positive results.
Other
Clinical Impact: There have been clinical reports of interactions with other drugs metabolized via the cytochrome P450 system (e.g., cyclosporine, disulfiram).
Intervention: Monitor patients to determine if it is necessary to adjust the dosage of these other drugs when taken concomitantly with PRILOSEC.

Table 4: Clinically Relevant Interactions Affecting Omeprazole When Co-Administered with Other Drugs

CYP2C19 or CYP3A4 Inducers
Clinical Impact: Decreased exposure of omeprazole when used concomitantly with strong inducers [see CLINICAL PHARMACOLOGY].
Intervention: St. John’s Wort, rifampin: Avoid concomitant use with PRILOSEC [see WARNINGS AND PRECAUTIONS]. Ritonavir-containing products: see prescribing information for specific drugs.
CYP2C19 or CYP3A4 Inhibitors
Clinical Impact: Increased exposure of omeprazole [see CLINICAL PHARMACOLOGY].
Intervention: Voriconazole: Dose adjustment of PRILOSEC is not normally required. However, in patients with Zollinger-Ellison syndrome, who may require higher doses, dose adjustment may be considered.
See prescribing information for voriconazole.

Read the entire FDA prescribing information for Prilosec (Omeprazole)

© Prilosec Patient Information is supplied by Cerner Multum, Inc. and Prilosec Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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