Background: Immediate-release omeprazole has a more rapid absorption compared with delayed-release omeprazole in asymptomatic volunteers. However, effects of delayed gastric emptying on omeprazole absorption remain unknown.
Aim: To compare pharmacokinetics between immediate and delayed-release omeprazole in patients with GERD associated with gastroparesis.
Methods: Open-label, randomized, cross-over study was performed. Antireflux and prokinetic medications were discontinued. Subjects were randomized into: (i) Immediate-release omeprazole 40 mg suspension o.m. for 7 days, wash-out for 10-14 days, followed by delayed-release omeprazole 40 mg capsule o.m. for 7 days, or (ii) the same schedule in reverse order. On day 7, omeprazole concentrations were obtained before and up to 5 h after taking the study drug. Patient Assessment of GI Disorders-Symptom Severity Index was obtained.
Results: A total of 12 women (mean age 51 years) completed the protocol. Time to maximal omeprazole concentration was significantly shorter for omeprazole. Maximal concentration was significantly greater for omeprazole, but total area under concentration-time curves was similar. Pharmacokinetic profile was less variable for immediate compared with delayed-release omeprazole.
Conclusions: Immediate-release omeprazole was associated with a more rapid absorption and less variable pharmacokinetic profile compared with delayed-release omeprazole in reflux patients associated with gastroparesis.