Dexlansoprazole (Jemtesa) and Quetiapine (Seroquel): No Clinically Significant Interaction
There is no clinically significant drug-drug interaction between dexlansoprazole and quetiapine, and these medications can be safely coadministered without dose adjustment or special monitoring beyond standard clinical care.
Pharmacokinetic Basis for Safety
The lack of interaction is supported by the distinct metabolic pathways and mechanisms of these agents:
Dexlansoprazole does not inhibit CYP3A4 or CYP2C19 at clinically relevant concentrations. Multiple drug interaction studies demonstrated that dexlansoprazole MR 90 mg (higher than typical therapeutic doses) had no effect on drugs metabolized by CYP2C19, CYP2C9, CYP1A2, or CYP3A, with 90% confidence intervals for AUC and Cmax ratios remaining within the bioequivalency range of 0.80-1.25 1.
Quetiapine is primarily metabolized by CYP3A4, but dexlansoprazole has been specifically studied and shown not to affect CYP3A4 substrates 1. This distinguishes dexlansoprazole from omeprazole, which does cause clinically significant interactions with certain drugs like benzodiazepines 2.
Dexlansoprazole's dual delayed release formulation achieves peak concentrations at different times (2 and 5 hours post-dose) but maintains a low risk of drug interactions compared to other proton pump inhibitors 3, 4.
Clinical Management
When prescribing these medications together:
No dose adjustment is required for either medication based on the coadministration 1.
Standard monitoring for each drug's individual adverse effects remains appropriate: sedation and metabolic effects for quetiapine 5, and typical PPI-related concerns for dexlansoprazole 3.
Timing of administration is flexible since dexlansoprazole can be taken without regard to meals or other medications 4, and quetiapine dosing is independent of PPI administration.
Important Caveats
Hepatic impairment requires caution with quetiapine due to inter-subject variability in clearance, though this is unrelated to dexlansoprazole coadministration 5. Start quetiapine at 25 mg and titrate carefully in cirrhotic patients 5.
The evidence base specifically addresses dexlansoprazole, not other PPIs. Omeprazole, for example, has documented interactions with drugs metabolized by CYP2C19 2, so this safety profile should not be extrapolated to all proton pump inhibitors.
Elderly patients and those with multiple comorbidities warrant closer monitoring due to polypharmacy risks generally 2, but this is not specific to the dexlansoprazole-quetiapine combination.