Esomeprazole is a competitive inhibitor of the enzyme CYP2C19, and may therefore interact with drugs that depend on it for metabolism, such as diazepam and warfarin; the concentrations of these drugs may increase if they are used concomitantly with esomeprazole.[26] Conversely, clopidogrel (Plavix) is an inactive prodrug that partially depends on CYP2C19 for conversion to its active form; inhibition of CYP2C19 blocks the activation of clopidogrel, thus reducing its effects.[27][28]