Pirfenidone

Products

Pirfenidone is commercially available in the form of hard capsules and film-coated tablets (Esbriet). It was approved in Japan in 2008 (Pirespa), in the EU in 2011, in the United States in 2014, and in many countries in 2015.

Structure and properties

Pirfenidone or 5-methyl-1-phenyl-2-1(H)-pyridone (C12H11NO, Mr = 185.2 g/mol) is a phenylpyridone. It exists as a white to pale yellow, non-hygroscopic powder.

Effects

Pirfenidone (ATC L04AX05) has antifibrotic and anti-inflammatory properties. It has a short half-life of approximately 2.4 hours. Pirfenidone reduces:

  • The accumulation of inflammatory cells.
  • Fibroblast proliferation.
  • The formation of fibrosis-associated proteins and cytokines.
  • The increased biosynthesis and accumulation of extracellular matrix.

Indications

For the treatment of idiopathic pulmonary fibrosis.

Dosage

According to the SmPC.

Contraindications

  • Hypersensitivity
  • Concurrent administration of fluvoxamine
  • Severe hepatic impairment
  • Terminal hepatic failure
  • Severe renal dysfunction

Full precautions can be found in the drug label.

Interactions

Pirfenidone is metabolized primarily by CYP1A2. CYP1A2 inhibitors such as fluvoxamine and grapefruit juice may cause a relevant increase in plasma concentrations. Conversely, smoking may induce CYP1A2 and decrease levels.

Adverse effects

The most common potential adverse effects include nausea, rash, fatigue, diarrhea, dyspepsia, and photosensitization.