What it's for (Indications)
- Pirfenidone is indicated for the treatment of Idiopathic Pulmonary Fibrosis (IPF).
- IPF is a chronic, progressive, and ultimately fatal fibrotic lung disease of unknown etiology, characterized by a progressive decline in lung function.
- The disease typically affects adults, primarily those over 50 years of age, and leads to irreversible scarring of the lung tissue, impairing oxygen exchange and significantly reducing quality of life.
- Pirfenidone functions as an anti-fibrotic agent, aiming to slow the progression of the disease and preserve lung function, thereby improving clinical outcomes such as forced vital capacity (FVC) decline and reducing the risk of respiratory-related hospitalizations or mortality.
- It is not a cure for IPF but is a critical disease-modifying therapy.
Dosage Information
| Type | Guideline |
|---|---|
| Standard | The recommended dosage of pirfenidone involves a gradual dose escalation over a 14-day period to reach the full maintenance dose. Initial therapy begins with 267 mg orally, three times daily, for the first 7 days. During Week 2 (Days 8-14), the dose is increased to 534 mg orally, three times daily. From Week 3 (Day 15) onwards, the maintenance dose is 801 mg orally, three times daily, for a total daily dose of 2403 mg. Pirfenidone capsules must be taken with food to minimize gastrointestinal side effects. If therapy is interrupted for 14 days or longer, treatment should be re-initiated with the 267 mg three times daily dose and re-titrated over two weeks to the maintenance dose. Dose reductions or interruptions may be necessary to manage adverse reactions, particularly gastrointestinal or liver-related toxicities, based on clinical judgment and liver function test results. |
Safety & Warnings
Common Side Effects
- Pirfenidone is associated with several adverse effects, ranging from common and mild to serious and potentially life-threatening.
- Common side effects, frequently observed during clinical trials, include nausea, fatigue, rash, photosensitivity reactions, diarrhea, dyspepsia, abdominal pain, anorexia (decreased appetite), headache, dizziness, insomnia, and arthralgia.
- These are often manageable with supportive care, dose reduction, or temporary interruption.
- More serious adverse effects, though less frequent, necessitate careful monitoring and prompt medical intervention.
- These include severe hepatotoxicity, evidenced by significant elevations in liver enzymes (ALT, AST) and bilirubin, which can lead to drug-induced liver injury.
- Other serious concerns are severe cutaneous adverse reactions (SCARs), such as Stevens-Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN), and angioedema or other hypersensitivity reactions.
- Patients should be thoroughly counseled on recognizing and reporting any signs of severe adverse events.
Serious Warnings
- Black Box Warning: PIRFENIDONE DOES NOT CARRY AN OFFICIAL FDA BLACK BOX WARNING. However, healthcare professionals and patients should be aware of several serious safety concerns that warrant rigorous monitoring and management, often detailed as 'Serious Warnings' in prescribing information due to their potential for severe patient harm. These include: **1. Severe Hepatotoxicity:** Pirfenidone can cause significant and potentially life-threatening drug-induced liver injury. Elevations in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) enzymes, sometimes accompanied by hyperbilirubinemia, have been observed. Regular monitoring of liver function tests (ALT, AST, and bilirubin) is mandatory at baseline, monthly for the first six months of treatment, and every three months thereafter, or as clinically indicated. Patients should be advised to report symptoms suggestive of liver injury immediately, such as jaundice, dark urine, or right upper quadrant abdominal pain. Dose reductions, temporary interruptions, or permanent discontinuation of pirfenidone may be necessary based on the severity of liver enzyme elevations. **2. Photosensitivity and Severe Cutaneous Reactions:** Patients treated with pirfenidone are at increased risk of photosensitivity reactions and rash, which can range from mild to severe. Patients must be counselled on strict sun protection measures, including avoiding direct sun exposure, wearing protective clothing, and using broad-spectrum sunscreens with a high SPF. Rare but serious cutaneous adverse reactions (SCARs), including drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson Syndrome (SJS), and toxic epidermal necrolysis (TEN), have been reported globally. Any severe or widespread rash, blistering, or mucosal lesions should prompt immediate medical evaluation and potential discontinuation of pirfenidone. **3. Gastrointestinal Intolerance:** A high incidence of gastrointestinal adverse effects, including nausea, diarrhea, dyspepsia, and abdominal pain, has been observed with pirfenidone. These symptoms can be severe enough to necessitate dose reduction or discontinuation. Patients should be advised to take pirfenidone with food to mitigate these effects and should report persistent or severe gastrointestinal symptoms to their healthcare provider for appropriate management.
- Several critical warnings and precautions are associated with pirfenidone therapy.
- Patients are at risk of significant liver enzyme elevations (ALT, AST) and hyperbilirubinemia, necessitating vigilant monitoring of liver function tests (LFTs) at baseline, monthly for the first 6 months, and every 3 months thereafter, or as clinically indicated.
- Dose adjustments or discontinuations may be required based on LFT results.
- Photosensitivity reactions and rash are common, ranging from mild erythema to severe skin reactions.
- Patients must be advised to avoid direct sun exposure, use broad-spectrum sunscreens, and wear protective clothing while on therapy.
- Severe cutaneous adverse reactions (SCARs), including drug reaction with eosinophilia and systemic symptoms (DRESS), have been reported rarely.
- Gastrointestinal intolerance, including severe nausea, diarrhea, and dyspepsia, is frequently encountered and often managed by taking the medication with food, dose reduction, or symptomatic treatment.
- Hypersensitivity reactions, such as angioedema, have occurred; patients experiencing these symptoms should discontinue the drug immediately and seek emergency medical care.
- Concomitant use with strong CYP1A2 inhibitors can significantly increase pirfenidone exposure, elevating the risk of adverse reactions.
How it Works (Mechanism of Action)
Pirfenidone is a novel anti-fibrotic agent with demonstrated anti-inflammatory properties, though its precise mechanism of action in Idiopathic Pulmonary Fibrosis (IPF) is not fully elucidated. It is believed to exert its therapeutic effects by inhibiting the synthesis of various pro-fibrotic and pro-inflammatory mediators. Key targets include transforming growth factor-beta (TGF-beta), a crucial cytokine implicated in fibroblast proliferation, differentiation into myofibroblasts, and extracellular matrix production, which are central to the pathogenesis of fibrosis. Pirfenidone also appears to modulate the expression of tumor necrosis factor-alpha (TNF-alpha), another important inflammatory cytokine. By suppressing these pathways, pirfenidone is thought to reduce fibroblast proliferation, decrease collagen and other fibrotic protein production, and attenuate inflammation, thereby slowing the progressive scarring and decline in lung function characteristic of IPF. Its multifaceted action contributes to its disease-modifying capabilities.
Commercial Brands (Alternatives)
No other brands found for this formula.