In FASS (The Swedish Catalogue of Approved Medical Products) the recommended dose of omeprazole is

Fråga: In FASS (The Swedish Catalogue of Approved Medical Products) the recommended dose of omeprazole is 20 mg when administrated perorally and 40 mg when administrated intravenously. Does this mean that peroral administration is more effective?

Sammanfattning: The reason why 40 mg is the recommended dose for intravenous omeprazole is that most studies of intravenous omeprazole have been performed using this dose. In two small studies 10 mg intravenous omeprazole was as effective (or nearly as effective) in lowering intragastric acidity as 20 mg of peroral omeprazole, indicating that intravenous administration is about twice as effective.

Svar: A search in Drugline, Medline and pharmacology literature gave two omeprazole studies comparing intravenous and peroral administration (1, 2). One of the studies was done in nine healthy volunteers and the other in nine patients with duodenal ulcer disease. Both compared 20 mg peroral omeprazole with 10 and 40 mg intravenous omeprazole. In both studies 10 mg intravenous omeprazole was as effective (or nearly as effective) as 20 mg peroral omeprazole in lowering the intragastric acidity on day one and five. A one day treatment of 40 mg intravenous omeprazole was as effective in lowering intragastric acidity, as a five day treatment of 20 mg peroral omeprazole daily. (The reduction in intragastric acidity was in the patient group 42.2 per cent, 54.8 per cent and 88.4 per cent on day one and 99.9 per cent, 95.7 per cent and 99.9 per cent on day 5 for the 20 mg peroral administration, the 10 mg and 40 mg intravenous administration respectively. In the volunteer group the reduction was 18 per cent, 15 per cent and 71 per cent on day one and 60 per cent, 53 per cent and 71 per cent on day 5 for the 20 mg peroral administration, the 10 mg and 40 mg intravenous administration respectively.) According to Astra Hässle the reason that the recommended intravenous omeprazole dose is higher than the peroral dose is that most studies of intravenous omeprazole were performed using 40 mg (3). The difference in dosage recommendation might also reflect differences in the clinical condition of patients for whom intravenous and oral treatments are prescribed.