[Evaluation of unexpected and toxic effects of omeprazole (Mopral) reported to the regional centers of pharmacovigilance during the first 22 postmarketing months].

Omeprazole has been marketed in France since 1989, for the healing of peptic ulcers, erosive reflux esophagitis and the Zollinger Ellison syndrome. It is a proton pump inhibitor which inhibits the acid secretion in the stomach. In the majority of the clinical trials, omeprazole has been found to be well tolerated: headache, dizziness, skin rash, constipation have just been noted. Since September 1989, 143 adverse reactions have been reported to pharmacovigilance centres and Astra France: 37 neurological and psychiatric side effects, especially confusion in patients with hepatic diseases and/or advanced age; 35 cutaneous reactions, generally rash and urticaria; 22 hematological effects: leucopenia and agranulocytosis have been reported but the relation with omeprazole is very uncertain; 10 gastrointestinal effects, generally diarrhoea, nausea, vomiting and abdominal pain; 8 hepatic disorders, especially moderate elevation of aminotransferases. This study confirms the safety of this drug, during short treatment; the frequency of notified adverse effects is about 1/12 200 treatments of 4 weeks. The ministry of health, has decided, in november 1991, to inform the prescribers of this potential toxicity of omeprazole, particularly, of the risk of confusion, hepatotoxicity and leucopenia.