On one hand, the pharmacist suggested to the physician at the outpatient clinic that the decrease in vitamin K intake due to anorexia and the change from bosentan to macitentan resulted in the cancellation of CYP2C9 and CYP3A4 enzyme induction by bosentan, enhancing the anticoagulant effect of warfarin, and the patient’s PT-INR could be prolonged. The gene discussed is CYP2C9; the disease is Anorexia.