Drug utilisation review of omeprazole

Objective: To assess the appropriateness of prescribing of omeprazole in a 100-bed Repatriation teaching hospital. Study Procedure: A drug utilisation review of omeprazole was retrospectively performed. The medical records of all 80 patients who had been prescribed omeprazole during 1991 were studied. The reasons for prescribing the drug were compared with the guidelines of the hospital (Pharmaceutical Benefits Scheme criteria).

Results: In general, the patients were elderly (median age: 71 years and range: 51-91 years; 59 males). The most common indications for using omeprazole were severe refractory ulcerating oesophagitis (31%) and refractory peptic ulcer (20%). According to data extracted from the medical records, the prescribing of omeprazole satisfied the hospital criteria in 51% of cases. Instances of usage that failed to meet these criteria included gastrointestinal bleeding of unknown origin (14%), inadequate duration of therapy with a H2-antagonist before commencing omeprazole for either ulcerating oesophagitis (6%) or peptic ulcer (3%), dyspepsia (4%), mild/moderate oesophageal reflux (4%), and to differentiate between chest pain of possible cardiac or gastrointestinal origin (6%). The duration of therapy exceeded 8 weeks in 50 patients (63%). The prescribed daily dosage of omeprazole was either 20 mg (84% of patients) or 40 mg (16%). Adverse effects had been documented for only two patients (constipation and severe rash).

Conclusions: While the prescribing of omeprazole generally appeared to comply with the hospital criteria, significant scope for improvement was also evident. Reasons for not satisfying the criteria mainly related to the use of omeprazole for other indications, rather than to an inadequate trial of H2-antagonists for peptic ulcer or ulcerating oesophagitis before commencing omeprazole. Until the cost of therapy with omeprazole approaches that for the H2-antagonists and until its long-term safety is established, the usage of omeprazole should be closely monitored and pharmacists should continue to endeavour to promote the rational use of the drug.