Omeprazole-induced blood dyscrasia in a clozapine-treated patient.

Proton pump inhibitors are among the world's most widely used therapeutic classes. Much of their use is attributed to their documented efficacy and apparent safety. For the most part, proton pump inhibitors are well tolerated with very few serious adverse events reported in the literature. Only a few previously identified case reports of severe neutropenia or agranulocytosis attributed to proton pump inhibitors use have been identified in the literature. However, agranulocytosis, neutropenia, and/or leukopenia are labeled as possible adverse events from post-marketing surveillance in the summary of product information for various proton pump inhibitors. In this report, we describe a case of probable omeprazole-induced blood dyscrasia in a clozapine-treated patient.