The anti-secretory effect and pharmacokinetics of omeprazole in chronic liver disease.

The anti-secretory effects and pharmacokinetics of omeprazole were investigated in ten patients with chronic liver disease. Plasma omeprazole concentrations were measured after a 10-mg intravenous dose of omeprazole and on the first and seventh days of a 7-day course of 10 mg oral omeprazole daily. Pentagastrin tests were performed on the day before oral omeprazole was commenced and 24 h after the last oral dose. The pre-treatment basal and peak gastric acid outputs were low (mean rates of 1.44 mmol/h and 9.26 mmol/h, respectively) and following 7 days of oral 10 mg omeprazole daily, were lowered by 95% and 90% respectively. Following 10 mg intravenous omeprazole, plasma clearance was reduced, and plasma half-life and area under the concentration curve were increased, in comparison with previous studies in healthy subjects. The plasma concentration curves for oral and intravenous doses were very similar. After both the first and seventh oral doses, maximum plasma concentration and area under the curve were higher than in healthy subjects. No accumulation of omeprazole was demonstrated. The pharmacokinetics of omeprazole in chronic liver disease could be influenced by low gastric acidity, poor liver function and/or portasystemic shunting. A dose of 10 mg omeprazole daily has been shown to be an effective anti-secretory agent in chronic liver disease.