Pirfenex 200 mg tablet contains Pirfenidone as its active ingredient. It is used to treat a lung disease called Idiopathic Pulmonary Fibrosis (IPF). It is meant for use only in adults. It should be taken as directed by the doctor and in doses and duration as prescribed. It should be taken with or after food. You should avoid being in the sunlight for too long and do not smoke while on treatment with Pirfenex 200 mg tablet. Before using this medicine, inform the doctor if you are pregnant, planning a pregnancy or breastfeeding and about your detailed medical history.