Some side effects of omeprazole, while occurring infrequently, are potentially serious and should be reported immediately to your healthcare provider. These include, but are not limited to:
Depression, agitation, aggression, hallucinations, or confusion
Signs of liver damage, such as yellowing in the whites of the eyes or skin, dark urine, or upper abdominal pain (or stomach pain)
Signs of an allergic reaction, including an unexplained rash, hives, itching, and unexplained swelling.
Rare Omeprazole Side Effects
Rare side effects of omeprazole occur in less than 1 percent of people taking the drug. Because these side effects are so uncommon, it can be difficult to tell whether they are actually caused by omeprazole or by factors unrelated to the medication.
Some of these rare side effects include, but are not limited to: