Pirfenidone

How it works

It has antifibrotic and anti-inflammatory actions, attenuating fibroblast proliferation and the production of fibrosis-associated mediators and collagen, although its precise mechanism is not fully defined.

Prescribing in practice

• Photosensitivity and rash are common, so strict sun protection and avoidance of strong sunlight are essential.
• Hepatotoxicity can occur, requiring liver function testing before and during treatment with dose adjustment for derangement.
• Gastrointestinal upset is common; taking doses with food improves tolerability, and smoking can reduce drug exposure.

Monitoring

Check liver function before starting and periodically during treatment, and monitor for skin reactions, gastrointestinal effects and weight loss.

Counselling the patient

• Use high-factor sun cream, cover up and avoid sunbeds while taking this medicine.
• Take the capsules with food to reduce nausea and report yellowing of the skin or eyes.
• Tell your doctor if you smoke, as it can affect how this medicine works.

Evidence & guidelines

The ASCEND and CAPACITY trials showed that pirfenidone slows lung function decline in idiopathic pulmonary fibrosis, supporting NICE-recommended use.