Centers for Education &
Research on Therapeutics™
Cytochrome P450 2C19
§Absent in 20–30% of Asians,
 3–5% Caucasians
§Primary metabolism of:
–Diazepam
–Phenytoin
–Omeprazole
§Inhibited by:
–Omeprazole
–Isoniazid
–Ketoconazole