Omeprazole side effects

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

List of side effects

Occurrence in ≥ 1% of patients

• U.S. clinical trial
• International clinical trial

Occurrence in < 1% of patients

Combination therapy for H. pylori eradication

• Triple therapy (omeprazole/clarithromycin/amoxicillin)
• Dual therapy (omeprazole/clarithromycin)

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Occurrence in ≥ 1% of patients

Omeprazole was generally well tolerated during domestic and international clinical trials in 3096 patients. The incidence of clinical adverse experiences in patients greater than 65 years of age was similar to that in patients 65 years of age or less. Return to top

U.S. clinical trial

In the U.S. clinical trial population of 465 patients (including duodenal ulcer, Zollinger-Ellison syndrome and resistant ulcer patients), the following adverse experiences were reported to occur in 1% or more of patients on therapy with Omeprazole: headache, diarrhea, abdominal pain, nausea, URI, dizziness, vomiting, rash, constipation, cough, asthenia, back pain. Return to top

International clinical trial

The following adverse reactions which occurred in 1% or more of Omeprazole-treated patients have been reported in international double-blind, and open-label, clinical trials in which 2,631 patients and subjects received Omeprazole: abdominal pain, asthenia, constipation, diarrhea, flatulence, nausea, vomiting, acid regurgitation, headache. Return to top

Occurrence in < 1% of patients

Additional adverse experiences occurring in < 1% of patients or subjects in domestic and/or international trials, or occurring since the drug was marketed, are shown below within each body system. In many instances, the relationship to Omeprazole was unclear.

• Body As a Whole: Allergic reactions, including, rarely, anaphylaxis (see also Skin below), fever, pain, fatigue, malaise, abdominal swelling
• Cardiovascular: Chest pain or angina, tachycardia, bradycardia, palpitation, elevated blood pressure, peripheral edema
• Gastrointestinal: Pancreatitis (some fatal), anorexia, irritable colon, flatulence, fecal discoloration, esophageal candidiasis, mucosal atrophy of the tongue, dry mouth, stomatitis. During treatment with Omeprazole, gastric fundic gland polyps have been noted rarely. These polyps are benign and appear to be reversible when treatment is discontinued.
• Gastro-duodenal 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: Mild and, rarely, marked elevations of liver function tests [ALT (SGPT), AST (SGOT), γ-glutamyl transpeptidase, alkaline phosphatase, and bilirubin (jaundice)]. In rare instances, overt liver disease has occurred, including hepatocellular, cholestatic, or mixed hepatitis, liver necrosis (some fatal), hepatic failure (some fatal), and hepatic encephalopathy.
• Metabolic/Nutritional: Hyponatremia, hypoglycemia, weight gain
• Musculoskeletal: Muscle cramps, myalgia, muscle weakness, joint pain, leg pain
• Nervous System/Psychiatric: Psychic disturbances including depression, agitation, aggression, hallucinations, confusion, insomnia, nervousness, tremors, apathy, somnolence, anxiety, dream abnormalities; vertigo; paresthesia; hemifacial dysesthesia
• Respiratory: Epistaxis, pharyngeal pain
• Skin: Rash and, rarely, cases of severe generalized skin reactions including toxic epidermal necrolysis (TEN; some fatal), Stevens-Johnson syndrome, and erythema multiforme (some severe); purpura and/or petechiae (some with rechallenge); skin inflammation, urticaria, angioedema, pruritus, photosensitivity, alopecia, dry skin, hyperhidrosis
• Special Senses: Tinnitus, taste perversion
• Ocular: Blurred vision, ocular irritation, dry eye syndrome, optic atrophy, anterior ischemic optic neuropathy, optic neuritis, double vision
• Urogenital: Interstitial nephritis (some with positive rechallenge), urinary tract infection, microscopic pyuria, urinary frequency, elevated serum creatinine, proteinuria, hematuria, glycosuria, testicular pain, gynecomastia
• Hematologic: Rare instances of pancytopenia, agranulocytosis (some fatal), thrombocytopenia, neutropenia, leukopenia, anemia, leucocytosis, and hemolytic anemia have been reported.

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Combination therapy for H. pylori eradication

In clinical trials using either dual therapy with Omeprazole and clarithromycin, or triple therapy with Omeprazole, clarithromycin, and amoxicillin, no adverse experiences peculiar to these drug combinations have been observed. Adverse experiences that have occurred have been limited to those that have been previously reported with Omeprazole, clarithromycin, or amoxicillin. Return to top

Triple therapy (omeprazole/clarithromycin/amoxicillin)

The most frequent adverse experiences observed in clinical trials using combination therapy with Omeprazole, 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 the antimicrobial drugs alone. Return to top

Dual therapy (omeprazole/clarithromycin)

Adverse experiences observed in controlled clinical trials using combination therapy with Omeprazole and clarithromycin (n = 346) which differed from those previously described for Omeprazole alone were: Taste perversion (15%), tongue discoloration (2%), rhinitis (2%), pharyngitis (1%) and flu syndrome (1%). Return to top

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Adapted from the FDA Package Insert.