24-HOUR INTRAGASTRIC ACIDITY AND PLASMA GASTRIN DURING 3-MONTH TREATMENT WITH OMEPRAZOLE IN HEALTHY-SUBJECTS

Background: Prolonged treatment with omeprazole 20 or 40 mg/day is som etimes required, especially for severe oesophagitis. However, informat ion about long-term effects on intragastric acidity and plasma gastrin response with such drug regimens is scarce. Methods: Sixteen healthy subjects (11 men, 5 women, mean age 29 years) randomly received either 20 or 40 mg of omeprazole once daily (at 08.00 h) for 3 months. Gastr ic pH was recorded every 6 s for 24 h from noon to noon under standard ized conditions, and blood samples were collected hourly in order to d etermine the 24-h plasma gastrin response on day 0 (pre-entry), day 7, day 28 and day 90. Results: From day 0 to day 7, 24-h median pH incre ased from 1.7 to 4.6 and mean percentage of time at pH < 4 decreased f rom 89% to 35% with omeprazole 20 mg. Respective values with omeprazol e 40 mg were 1.9 to 4.3, and 89% to 34%. Inhibition of gastric acidity remained unchanged during the 3 months of treatment. Despite similar effects on the basis of 24-h analysis, the decrease in daytime acidity was slightly higher with omeprazole 40 mg than with omeprazole 20 mg. Twenty-four-hour integrated plasma gastrin significantly increased wi th both drug regimens between day 0 and day 7 (P < 0.01), and between day 7 and day 28 (P < 0.01) with omeprazole 40 mg; there was no signif icant increase between day 28 and day 90 with either of the drug regim ens. Conclusion: Omeprazole 20 and 40 mg/day provides long-term stable acid suppression with a progressive increase in gastrin response, sta bilizing after 2 months of treatment.