Esbriet (Pirfenidone) may be used to treat adults with idiopathic pulmonary fibrosis (IPF), a lung condition that causes inflammation and scarring in the lungs. Esbriet’s mechanism of action involves slowing down the build-up of scar tissue in the lungs. The exact way it works for IPF is not known, but it does have anti-inflammatory, antioxidant, and anti-fibrotic properties.