Omeprazole was generally well tolerated during domestic and international clinical trials in 3096 patients.
In the U.S. clinical trial population of 465 patients, the adverse experiences summarized in Table 11 were reported to occur in 1% or more of patients on therapy with omeprazole. Numbers in parentheses indicate percentages of the adverse experiences considered by investigators as possibly, probably or definitely related to the drug.
Table 11: Adverse Experiences Occurring in 1% or More of Patients on Omeprazole Therapy
| Omeprazole |
(n = 465)
| Placebo |
(n = 64)
| Ranitidine |
(n = 195)
|Headache||6.9 (2.4)||6.3||7.7 (2.6)|
|Diarrhea||3.0 (1.9)||3.1 (1.6)||2.1 (0.5)|
|Abdominal Pain||2.4 (0.4)||3.1||2.1|
|Nausea||2.2 (0.9)||3.1||4.1 (0.5)|
|Dizziness||1.5 (0.6)||0.0||2.6 (1.0)|
|Vomiting||1.5 (0.4)||4.7||1.5 (0.5)|
|Asthenia||1.1 (0.2)||1.6 (1.6)||1.5 (1.0)|
Table 12 summarizes the adverse reactions that occurred in 1% or more of omeprazole-treated patients from international double-blind, and open-label clinical trials in which 2,631 patients and subjects received omeprazole.
Table 12: Incidence of Adverse Experiences ≥ 1%; Causal Relationship not Assessed
| Omeprazole |
(n = 2631)
| Placebo |
(n = 120)
|Body as a Whole, site unspecified|
| Abdominal pain||5.2||3.3|
| Vomiting||3.2||10.0 |
| Acid regurgitation||1.9||3.3|
Additional adverse experiences occurring in < 1% of patients or subjects in domestic and/or international trials conducted with omeprazole, 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.
Chest pain or angina, tachycardia, bradycardia, palpitation, elevated blood pressure, and peripheral edema.
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.
Gastroduodenal carcinoids have been reported in patients with Zollinger-Ellison 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.
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.
Hyponatremia, hypoglycemia, and weight gain.
Muscle cramps, myalgia, muscle weakness, joint pain, and leg pain.
Psychic disturbances including depression, agitation, aggression, hallucinations, confusion, insomnia, nervousness, tremors, apathy, somnolence, anxiety, dream abnormalities; vertigo; paresthesia; and hemifacial dysesthesia.
Epistaxis, pharyngeal pain.
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, and hyperhidrosis.
Tinnitus, taste perversion.
Blurred vision, ocular irritation, dry eye syndrome, optic atrophy, anterior ischemic optic neuropathy, optic neuritis and double vision.
Interstitial nephritis (some with positive rechallenge), urinary tract infection, microscopic pyuria, urinary frequency, elevated serum creatinine, proteinuria, hematuria, glycosuria, testicular pain, and gynecomastia.
Rare instances of pancytopenia, agranulocytosis (some fatal), thrombocytopenia, neutropenia, leukopenia, anemia, leucocytosis, and hemolytic anemia have been reported.
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.
Additional adverse reactions that could be caused by sodium bicarbonate include metabolic alkalosis, seizures, and tetany.
The use of magnesium hydroxide is associated with diarrhea, abdominal cramping, chalky taste, diuresis, dehydration, nausea, and vomiting.