Proton pump inhibitors such as omeprazole and esomeprazole can interact with SSRI antidepressants like citalopram and escitalopram. These effects may be fairly minor compared to other medication interactions, but they are useful to be aware of in case they cause problems for patients. These interactions include:
1. Omeprazole increases plasma concentrations of (+)-(S)-citalopram by approximately 120%.
2. Omeprazole leads to a 51% increase in escitalopram exposure.
3. Omeprazole increases t(1/2) of escitalopram from 26.5 to 34.8 h.
Omeprazole preferentially inhibits the metabolism of (+)-(S)-citalopram in healthy volunteers. (Link)
The clinical pharmacokinetics of escitalopram. (Link)
The effect of cimetidine or omeprazole on the pharmacokinetics of escitalopram in healthy subjects. (Link)