Omed: The adverse effects reported most frequently with omeprazole have been gastrointestinal disturbances, in particular diarrhea, constipation, abdominal pain, nausea and vomiting and flatulence. Skin rash, pruritus and urticaria have also been reported, usually resolving after discontinuation of treatment.
Central nervous system disorders reported so far include paresthesia, dizziness, light-headedness and feeling faint, all of these usually resolved on cessation of therapy. Somnolence, insomnia, and vertigo have been reported rarely. Reversible mental confusion, agitation, depression and hallucinations have occurred predominantly in severely ill patients.
Other adverse events reported rarely include arthralgias and myalgia, blurred vision, taste disturbances, peripheral edema, hyponatremia, blood disorders including agranulocytosis, leucopenia, thrombocytopenia, pancytopenia, anaphylactic shock, malaise, fever, bronchospasm, encephalopathy in patients with preexisting severe liver disease, hepatitis with or without jaundice, rarely hepatic failure and interstitial nephritis which has resulted in acute renal failure.
Omed 20: The most common side effects are diarrhea, skin rashes, and headache. Other adverse effects reported rarely include arthralgia, and myalgia, blood disorders including leucopenia and thrombocytopenia, interstitial nephritis, and hepatotoxicity.