Effects of Omeprazole on the Pharmacokinetic Profiles of Lisdexamfetamine Dimesylate and Extended-Release Mixed Amphetamine Salts in Adults

Abstract

Total exposure was unaffected by omeprazole for both compounds. However, approximately 50% of subjects receiving MAS XR showed an earlier Tmax while on omeprazole, indicating unpredictable release of active drug by the second bead of MAS XR, most likely related to reduced stomach acid while on a PPI compromising the pulsed delivery of MAS XR. No clear trend was observed for LDX.