Omexac-20: The side effects reported most frequently with Omeprazole capsule have been diarrhoea, skin rashes, and headache; they have been sometimes been severe enough to require discontinuation of treatment. Effects on the central nervous system, including reversible states in severely ill patients, have occurred. Other adverse effects reported rarely include arthralgia and myalgia, blood disorder including leukopenia and thrombocytopenia, interstitial, nephritis, and hepatotoxicity.
Omexac-40: The most common side effects (1-10% of patients) are headache, abdominal pain, constipation, diarrhea, flatulence and nausea/vomiting. Irreversible visual impairment has been reported in isolated cases of critically ill patients who have received Omeprazole intravenous injection, especially at high doses, but no causal relationship has been established.