Co-administration of nelfinavir with inhibitors of CYP2C19 (e.g., fluconazole, fluoxetine, paroxetine, lansoprazole, imipramine, amitriptyline and diazepam) may be expected to reduce the conversion of nelfinavir to its major active metabolite M8 (tert-butyl hydroxy nelfinavir) with a concomitant increase in plasma nelfinavir levels (see section 5.2).