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Quick facts
- Drug class
- Pyridone [EPC]
- How it is given
- oral
- Type
- human prescription drug
- RxNorm ID
- 1592279
We do not publish dosing. How much of this medicine to take, how often, and for how long depends on your age, weight, kidney and liver function, other conditions and other medicines. That is a decision for the person who prescribes or dispenses it. Follow the directions on your own pack and ask your pharmacist if anything is unclear.
What it is used to treat
Pirfenidone capsules are indicated for the treatment of idiopathic pulmonary fibrosis (IPF). Pirfenidone is a pyridone indicated for the treatment of idiopathic pulmonary fibrosis (IPF). (1)
About this medicine
Pirfenidone, USP belongs to the chemical class of pyridone. Pirfenidone capsules, USP are available as a opaque white to off-white hard gelatin capsule containing 267 mg of pirfenidone, USP for oral administration. Pirfenidone, USP has a molecular formula of C12H11NO and a molecular weight of 185.22 g/mol. Pirfenidone, USP has the following structural formula, which has been referred to as 5-methyl-1-phenylpyridin-2-one. Pirfenidone, USP is a white to pale yellow, non-hygroscopic, crystalline powder. It is sparingly soluble in water, freely soluble in ethanol (96%), and slightly soluble in heptane. The melting point range is 107°C to 111°C. Each pirfenidone capsule, USP contains pirfenidone USP, 267 mg as active ingredient and the following inactive ingredients: croscarmellose sodium, hypromellose, lactose monohydrate, and magnesium stearate. In addition, the capsule shell contains gelatin and titanium dioxide. The capsule is imprinted with black pharmaceutical ink which includes butyl alcohol, dehydrated alcohol, ferrosoferric oxide, isopropyl alcohol, potassium hydroxide, propylene glycol, purified water, shellac, and strong ammonia solution. 10
How it works
12.1 Mechanism of Action The mechanism of action of pirfenidone in the treatment of IPF has not been established.
Warnings and cautions
Elevated liver enzymes and drug-induced liver injury: ALT, AST, and bilirubin elevations have occurred with pirfenidone including cases of drug-induced liver injury. In the post-marketing setting, non-serious and serious cases of drug-induced liver injury, including severe liver injury with fatal outcomes, have been reported. Monitor ALT, AST, and bilirubin before and during treatment. Temporary dosage reductions or discontinuations may be required. ( 2.1 , 5.1 ) Photosensitivity and rash: Photosensitivity and rash have been noted with pirfenidone. Avoid exposure to sunlight and sunlamps. Wear sunscreen and protective clothing daily. Temporary dosage reductions or discontinuations may be required. ( 5.2 ) Severe Cutaneous Adverse Reactions (SCAR): Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reactions with eosinophilia and systemic symptoms (DRESS) have been reported in association with the use of pirfenidone in the post-marketing setting. Interrupt pirfenidone in case of signs or symptoms of SCAR. Permanently discontinue pirfenidone if a SCAR is confirmed. ( 5.3 ) Gastrointestinal disorders: Nausea, vomiting, diarrhea, dyspepsia, gastro-esophageal reflux disease, and abdominal pain have occurred with pirfenidone. Temporary dosage reductions or discontinuations may be required. ( 5.4 ) 5.1 Elevated Liver Enzymes and Drug-Induced Liver Injury Cases of drug-induced liver injury (DILI) have been observed with pirfenidone. In the post-marketing period, non-serious and serious cases of DILI, including severe liver injury with fatal outcome, have been reported. Patients treated with pirfenidone 2,403 mg/day in three Phase 3 trials had a higher incidence of elevations in ALT or AST ≥ 3 × ULN than placebo patients (3.7% vs. 0.8%, respectively). Elevations ≥ 10 × ULN in ALT or AST occurred in 0.3% of patients in the pirfenidone 2,403 mg/day group and in 0.2% of patients in the placebo group. Increases in ALT and AST ≥ 3 × ULN were reversible with dose modification or treatment discontinuation. […]
Reported side effects
The following adverse reactions are discussed in greater detail in other sections of the labeling: Liver Enzyme Elevations and Drug-Induced Liver Injury [see Warnings and Precautions (5.1) ] Photosensitivity Reaction or Rash [see Warnings and Precautions (5.2) ] Severe Cutaneous Adverse Reactions [see Warnings and Precautions (5.3) ] Gastrointestinal Disorders [see Warnings and Precautions (5.4) ] The most common adverse reactions (≥ 10%) are nausea, rash, abdominal pain, upper respiratory tract infection, diarrhea, fatigue, headache, decreased appetite, dyspepsia, dizziness, vomiting, gastro-esophageal reflux disease, sinusitis, insomnia, weight decreased, and arthralgia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact AvKARE at 1-855-361-3993 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of pirfenidone has been evaluated in more than 1,400 subjects with over 170 subjects exposed to pirfenidone for more than 5 years in clinical trials. Pirfenidone was studied in 3 randomized, double-blind, placebo-controlled trials (Studies 1, 2, and 3) in which a total of 623 patients received 2,403 mg/day of pirfenidone and 624 patients received placebo. Subjects ages ranged from 40 to 80 years (mean age of 67 years). Most patients were male (74%) and Caucasian (95%). The mean duration of exposure to pirfenidone was 62 weeks (range: 2 to 118 weeks) in these 3 trials. At the recommended dosage of 2,403 mg/day, 14.6% of patients on pirfenidone compared to 9.6% on placebo permanently discontinued treatment because of an adverse event. The most common (> 1%) adverse reactions leading to discontinuation were rash and nausea. The most common (> 3%) adverse reactions leading to dosage reduction or interruption were rash, nausea, diarrhea, and photosensitivity reaction. […]
Interactions with other medicines
Moderate (e.g., ciprofloxacin) and strong inhibitors of CYP1A2 (e.g., fluvoxamine) increase systemic exposure of pirfenidone and may alter the adverse reaction profile of pirfenidone. Discontinue fluvoxamine prior to administration of pirfenidone or reduce to 267 mg three times a day. Consider dosage reduction with use of ciprofloxacin. ( 7.1 ) 7.1 CYP1A2 Inhibitors Pirfenidone is metabolized primarily (70% to 80%) via CYP1A2 with minor contributions from other CYP isoenzymes including CYP2C9, 2C19, 2D6 and 2E1. Strong CYP1A2 Inhibitors The concomitant administration of pirfenidone and fluvoxamine or other strong CYP1A2 inhibitors (e.g., enoxacin) is not recommended because it significantly increases exposure to pirfenidone [see Clinical Pharmacology (12.3)]. Use of fluvoxamine or other strong CYP1A2 inhibitors should be discontinued prior to administration of pirfenidone and avoided during pirfenidone treatment. In the event that fluvoxamine or other strong CYP1A2 inhibitors are the only drug of choice, dosage reductions are recommended. Monitor for adverse reactions and consider discontinuation of pirfenidone as needed [ see Dosage and Administration (2.4) ] . Moderate CYP1A2 Inhibitors Concomitant administration of pirfenidone and ciprofloxacin (a moderate inhibitor of CYP1A2) moderately increases exposure to pirfenidone [see Clinical Pharmacology (12.3)] . If ciprofloxacin at the dosage of 750 mg twice daily cannot be avoided, dosage reductions are recommended [see Dosage and Administration (2.4) ]. Monitor patients closely when ciprofloxacin is used at a dosage of 250 mg or 500 mg once daily. Concomitant CYP1A2 and other CYP Inhibitors Agents or combinations of agents that are moderate or strong inhibitors of both CYP1A2 and one or more other CYP isoenzymes involved in the metabolism of pirfenidone (i.e. CYP2C9, 2C19, 2D6, and 2E1) should be discontinued prior to and avoided during pirfenidone treatment. 7.2 CYP1A2 Inducers The concomitant use of pirfenidone and a CYP1A2 inducer may decrease the exposure of pirfenidone and this may lead to loss of efficacy. […]
Use in specific groups
Hepatic Impairment: Monitor for adverse reactions and consider dosage modification or discontinuation of pirfenidone as needed. Pirfenidone is not recommended for use in patients with severe hepatic impairment. ( 8.6 , 12.3) Renal Impairment: Monitor for adverse reactions and consider dosage modification or discontinuation of pirfenidone as needed. Pirfenidone is not recommended for use in patients with end stage renal disease on dialysis. ( 8.7 , 12.3) Smokers: Decreased exposure has been noted in smokers which may alter the efficacy profile of pirfenidone. ( 8.8 ) 8.1 Pregnancy Risk Summary The data with pirfenidone use in pregnant women are insufficient to inform on drug associated risks for major birth defects and miscarriage. In animal reproduction studies, pirfenidone was not teratogenic in rats and rabbits at oral doses up to 3 and 2 times, respectively, the maximum recommended daily dose (MRDD) in adults [see Data] . In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data Animal reproductive studies were conducted in rats and rabbits. In a combined fertility and embryofetal development study, female rats received pirfenidone at oral doses of 0, 50, 150, 450, and 1,000 mg/kg/day from 2 weeks prior to mating, during the mating phase, and throughout the periods of early embryonic development from gestation days (GD) 0 to 5 and organogenesis from GD 6 to 17. In an embryofetal development study, pregnant rabbits received pirfenidone at oral doses of 0, 30, 100, and 300 mg/kg/day throughout the period of organogenesis from GD 6 to 18. In these studies, pirfenidone at doses up to 3 and 2 times, respectively, the maximum recommended daily dose (MRDD) in adults (on mg/m 2 basis at maternal oral doses up to 1,000 mg/kg/day in rats and 300 mg/kg/day in rabbits, respectively) revealed no evidence of impaired fertility or harm to the fetus due to pirfenidone. […]
If too much is taken
There is limited clinical experience with overdosage. Multiple-dosages of pirfenidone up to a maximum tolerated dose of 4,005 mg per day were administered as five 267 mg capsules three times daily to healthy adult volunteers over a 12-day dose escalation. In the event of a suspected overdosage, appropriate supportive medical care should be provided, including monitoring of vital signs and observation of the clinical status of the patient.
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This page is built from the openFDA record of the U.S. Food and Drug Administration's approved labelling for this product, effective 14 January 2026. Label text has been shortened and reformatted for readability; safety wording has not been altered in meaning. FDA labelling describes products approved in the United States — brand names, strengths, formulations and approved uses may differ in your country. Always read the leaflet that comes with your own pack. PocketsInfo is not affiliated with, and is not endorsed by, the FDA. Retrieved 2026-07-30.