Most frequent adverse effects experienced with Omeprazole have been headache, diarrhea and skin rashes. They have sometimes been severe enough to discontinue the treatment. Other adverse effects include pruritus, dizziness, fatigue, constipation, nausea and vomiting, flatulence, abdominal pain, arthralgia and myalgia, urticaria and dry mouth. Isolated cases of photosensitivity, bullous eruption, erythema multiforme, angioedema and anaphylaxis have been reported. Effects on the CNS include occasional insomnia, somnolence and vertigo; reversible confusional states, agitation, depression, and hallucination have occurred in severely ill patients. Raised liver enzymes and isolated cases of hepatitis, jaundice and hepatic encephalopathy, have been reported. Other adverse effects reported rarely or in isolated cases include paraesthesia, blurred vision, alopecia, stomatitis, taste disturbance, peripheral edema, hyponatremia, blood disorders (including agranulocytosis, leucopenia and thrombocytopenia) and intestinal nephritis. Proton pump inhibitors may increase the risk of gastrointestinal infection because of their acid suppressive effects.