Formulary
Pirfenidone: Indications, Dosing, Side Effects and Interactions
The exact mechanism of action of pirfenidone is not yet understood, but it is believed to slow down the progression of idiopathic pulmonary fibrosis by...
MedNext Academy | 3 min read
Pirfenidone: Indications, Dosing, Side Effects and Interactions
The exact mechanism of action of pirfenidone is not yet understood, but it is believed to slow down the progression of idiopathic pulmonary fibrosis by...
Drug action
The exact mechanism of action of pirfenidone is not yet understood, but it is believed to slow down the progression of idiopathic pulmonary fibrosis by exerting both antifibrotic and anti-inflammatory properties.
Indications and dose
**Treatment of mild to moderate idiopathic pulmonary fibrosis (initiated under specialist supervision)**
- **Adult** (By Mouth): Initially 267 mg 3 times a day for 7 days, then increased to 534 mg 3 times a day for 7 days, then increased to 801 mg 3 times a day.
Cautions
Cautions, further information Photosensitivity Manufacturer advises avoid exposure to direct sunlight-if photosensitivity reaction or rash occurs, dose adjustment or treatment interruption may be required (consult product literature). Treatment interruption If treatment is interrupted for 14 consecutive days or more, the initial 2 week titration regimen should be repeated; if treatment is interrupted for less than 14 consecutive days, the dose can be resumed at the previous daily dose without titration.
Side effects
Common or very common Appetite decreased; arthralgia; asthenia; constipation; diarrhoea; dizziness; drowsiness; gastrointestinal discomfort; gastrointestinal disorders; headache; hot flush; increased risk of infection; insomnia; musculoskeletal chest pain; myalgia; nausea; photosensitivity reaction; productive cough; skin reactions; sunburn; taste altered; vomiting; weight decreased Uncommon Agranulocytosis; angioedema; hepatic disorders; hyponatraemia Frequency not known Severe cutaneous adverse reactions (SCARs) Side-effects, further information Gastrointestinal side-effects may require dose reduction or treatment interruption-consult product literature.
Interactions
**Severe interactions:**
- Co-administration of medicinal products that act as potent inducers of both CYP1A2 and the other CYP isoenzymes involved in the metabolism of pirfenidone (e.g.
**Other interactions (16):**
- Approximately 70-80% of pirfenidone is metabolised via CYP1A2 with minor contributions from other CYP isoenzymes including CYP2C9, 2C19, 2D6, and 2E1.
- Consumption of grapefruit juice is associated with inhibition of CYP1A2 and should be avoided during treatment with pirfenidone.
- Fluvoxamine and inhibitors of CYP1A2 In a Phase 1 study, the co-administration of Esbriet and fluvoxamine (a strong inhibitor of CYP1A2 with inhibitory effects on other CYP isoenzymes [CYP2C9, 2C19,...
- Fluvoxamine should be discontinued prior to the initiation of Esbriet therapy and avoided during Esbriet therapy due to the reduced clearance of pirfenidone.
- Other therapies that are inhibitors of both CYP1A2 and one or more other CYP isoenzymes involved in the metabolism of pirfenidone (e.g.
- CYP2C9, 2C19, and 2D6) should be avoided during pirfenidone treatment.
Pregnancy
Manufacturer advises avoid-no information available.
Breast feeding
Manufacturer advises avoid-no information available.
Hepatic impairment
Manufacturer advises caution in mild to moderate impairment (risk of increased exposure); avoid in severe impairment (no information available).
Renal impairment
Caution if creatinine clearance 30-50 mL/minute; avoid if creatinine clearance less than 30 mL/minute. M See Prescribing in renal impairment .
Medicinal forms
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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