The following cytochrome P450 (CYP)-enzymes are mainly involved in clozapine metabolism: CYP1A2 (30%), CYP2C19 (24%), CYP3A4 (22%), CYP2C9 (12%), and CYP2D6 (6%).103 Among them, CYP1A2 induction or inhibition can lead to clinically relevant changes in plasma clozapine levels.94,95 Inhibitors include caffeine,104 and C-reactive protein (CRP),105, –107 which can be triggered by infections. The gene discussed is CYP1A2; the disease is infection.