Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ESBRIET vs PIRFENIDONE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Pirfenidone inhibits TGF-β stimulated collagen production and reduces fibroblast proliferation, exhibiting anti-inflammatory and antifibrotic effects in pulmonary fibrosis.
Pirfenidone is a pyridone derivative that inhibits TGF-β1-mediated collagen synthesis, reduces fibroblast proliferation, and downregulates the production of pro-inflammatory cytokines (e.g., TNF-α, IL-1β) and growth factors. Its exact mechanism in idiopathic pulmonary fibrosis (IPF) is not fully elucidated, but it is thought to exert antifibrotic and anti-inflammatory effects.
Idiopathic pulmonary fibrosis (IPF)
Idiopathic pulmonary fibrosis (IPF)
801 mg three times daily orally with food.
801 mg orally three times daily with food, total daily dose 2403 mg. Starting dose: 267 mg three times daily for first 7 days, then 534 mg three times daily for 7 days, then maintenance 801 mg three times daily.
Terminal elimination half-life is approximately 3 hours (range 1.5-5 hours) in healthy adults. In patients with idiopathic pulmonary fibrosis, half-life is similar but exhibits interindividual variability.
Terminal elimination half-life: ~2.5 hours (range 1.5–3.5 h); clinical context: no accumulation with twice-daily dosing; steady-state reached within 2–3 days.
Primarily hepatic via CYP1A2 (major), with minor contributions from CYP2C9, CYP2C19, CYP2D6, and CYP2E1.
Primarily hepatic metabolism via CYP1A2, with minor contributions from other CYP enzymes (CYP2C9, CYP2C19, CYP2D6, CYP2E1).
Renal excretion of parent drug and metabolites accounts for approximately 99% of elimination, with about 82% recovered in urine and 1% in feces. Pirfenidone is extensively metabolized, with less than 1% excreted unchanged.
Renal: ~80% (mostly as unchanged drug and metabolites); fecal: ~20%.
Protein binding is approximately 50-58%, primarily to albumin.
~60–70% bound to plasma proteins (primarily albumin).
Volume of distribution is approximately 1.0 L/kg, indicating extensive tissue distribution.
Vd: ~1 L/kg (range 0.8–1.2 L/kg); clinical meaning: extensive tissue distribution.
Oral bioavailability is approximately 80% (range 70-90%) under fed conditions; food reduces peak concentration but increases total exposure.
Oral: ~80–85% (high bioavailability with minimal first-pass metabolism).
GFR 30-50 m L/min: 267 mg three times daily; GFR < 30 m L/min: not recommended.
Contraindicated in GFR < 30 m L/min. For GFR 30-50 m L/min: reduce to 267 mg three times daily; monitor for adverse effects. No adjustment for GFR > 50 m L/min.
Child-Pugh A: 801 mg three times daily; Child-Pugh B: 267 mg three times daily; Child-Pugh C: contraindicated.
Child-Pugh Class A: no adjustment. Child-Pugh Class B: contraindicated (insufficient data). Child-Pugh Class C: contraindicated.
Not established; safety and efficacy in pediatric patients have not been studied.
Not approved for pediatric patients; safety and efficacy not established. No weight-based dosing guidelines available.
No specific dose adjustment recommended; monitor renal function and consider lower starting dose due to age-related decline in renal function.
No specific dose adjustment required; use caution due to potential increased sensitivity and higher incidence of renal impairment. Monitor renal function and gastrointestinal tolerability.
None
No FDA black box warnings.
Hepatotoxicity: monitor liver function tests before and during treatment; discontinue if significant elevation.,Photosensitivity and rash: avoid sun exposure; use sunscreen.,Gastrointestinal effects: nausea, diarrhea, dyspepsia; take with food.,Elevated liver enzymes: dose reduction or interruption may be required.
Hepatotoxicity: Elevations in liver enzymes and potential drug-induced liver injury; monitor LFTs regularly.,Photosensitivity: Avoid sun exposure; use broad-spectrum sunscreen.,Gastrointestinal effects: Nausea, diarrhea, dyspepsia; may require dose adjustment.,Drug interactions: Coadministration with strong CYP1A2 inhibitors (e.g., fluvoxamine) increases pirfenidone exposure; use with caution.,Smoking: Tobacco smoking induces CYP1A2, reducing pirfenidone exposure; advise smoking cessation.
Severe hepatic impairment (Child-Pugh Class C),Severe renal impairment requiring dialysis,History of hypersensitivity to pirfenidone or any excipient
Severe hepatic impairment (Child-Pugh Class C),History of hypersensitivity to pirfenidone or any excipient,Coadministration with strong CYP1A2 inhibitors (e.g., fluvoxamine) due to potential toxicity
Take with meals to reduce GI intolerance. Grapefruit and grapefruit juice may increase pirfenidone blood levels and should be avoided. Avoid smoking as it induces CYP1A2 and may reduce drug efficacy.
Avoid grapefruit juice (CYP3A4 interaction). Take with food to minimize GI upset. No other significant food interactions.
Pirfenidone is teratogenic in animal studies, causing fetal malformations and embryotoxicity at clinically relevant exposures. There are no adequate human studies. Use during pregnancy is contraindicated; effective contraception is required before and during treatment. First trimester carries the highest risk for major congenital anomalies; second and third trimester risks include fetal growth restriction and potential pulmonary toxicity.
Pirfenidone is classified as FDA Pregnancy Category C. In animal studies, it caused fetal toxicity (reduced fetal weight, increased skeletal variations) at doses below human exposure. There are no adequate and well-controlled studies in pregnant women. The risk of major birth defects is unknown; use only if potential benefit justifies potential risk to the fetus. First trimester: potential for teratogenicity. Second and third trimester: possible fetal toxicity from maternal exposure.
No human data on milk excretion; animal studies show drug and metabolites present in breast milk. Unknown M/P ratio. Risk of infant toxicity cannot be excluded. Breastfeeding is not recommended during therapy and for 2 weeks after last dose.
It is unknown if pirfenidone is excreted in human breast milk. The M/P ratio has not been determined. Due to potential for serious adverse reactions in nursing infants, breastfeeding is not recommended during treatment and for at least 2 weeks after the last dose.
No established dosing guidelines for pregnancy. Significant pharmacokinetic changes (increased volume of distribution, renal clearance) may reduce drug exposure. Theoretical adjustments are not recommended due to unknown safety; therapy should be discontinued if pregnancy occurs. If continuation is deemed unavoidable, dose individualization based on therapeutic drug monitoring is suggested but unvalidated.
No specific dosing adjustments for pregnancy have been established. Due to changes in volume of distribution and renal clearance during pregnancy, therapeutic drug monitoring is not possible. Use lowest effective dose if absolutely necessary.
Pirfenidone (Esbriet) is an antifibrotic agent approved for idiopathic pulmonary fibrosis (IPF). It reduces decline in lung function but does not reverse fibrosis. Monitor liver function tests (LFTs) monthly for 6 months then every 3 months due to risk of hepatotoxicity. Photosensitivity is common; advise strict sun avoidance and broad-spectrum sunscreen. Dosage titration over 14 days reduces GI side effects. Avoid use with strong CYP1A2 inhibitors (e.g., fluvoxamine, ciprofloxacin) as they increase pirfenidone exposure.
Monitor liver function tests monthly for first 6 months, then every 3 months. Avoid use in moderate to severe hepatic impairment (Child-Pugh B/C). Photosensitivity is common; advise sun avoidance and broad-spectrum sunscreen. May cause gastrointestinal issues; take with food. Dose reduction required with strong CYP1A2 inhibitors (e.g., fluvoxamine). Smoking induces CYP1A2 and reduces exposure.
Take with food to reduce nausea and upset stomach.,Avoid sun exposure; wear protective clothing and apply sunscreen daily due to risk of severe sunburn.,Do not stop or change dose without consulting your doctor; taper is not required but missed doses should be skipped.,Report any signs of liver problems: yellowing of skin/eyes, dark urine, fatigue, or abdominal pain.,Avoid smoking and grapefruit products as they may affect drug levels.
Take with food to reduce stomach upset.,Avoid sun exposure; use sunscreen and protective clothing.,Report any signs of liver problems: jaundice, dark urine, abdominal pain.,Do not smoke while taking this medication.,Avoid grapefruit juice.,Complete blood tests as scheduled.
No interactions on record
"Pirfenidone, an antifibrotic agent used for idiopathic pulmonary fibrosis, may reduce the vasodilatory efficacy of alprostadil, a prostaglandin E1 analog. This interaction likely results from pirfenidone-induced downregulation of prostaglandin receptors or modulation of cyclic AMP signaling pathways, leading to diminished smooth muscle relaxation and reduced therapeutic response to alprostadil. Consequently, patients may experience suboptimal vasodilation, potentially compromising treatment for conditions like erectile dysfunction or peripheral arterial disease."
"Pirfenidone, an antifibrotic agent, may reduce the ocular hypotensive efficacy of bimatoprost, a prostaglandin analog used for glaucoma. This interaction is postulated to occur via pirfenidone's inhibitory effects on prostaglandin synthesis or signaling pathways, potentially attenuating bimatoprost-mediated enhancement of uveoscleral outflow. Clinically, patients may experience inadequate intraocular pressure (IOP) reduction, increasing the risk of glaucoma progression."
"Pindolol, a non-selective beta-blocker with intrinsic sympathomimetic activity, may antagonize the vasodilatory effects of pirfenidone, an antifibrotic agent known to reduce systemic vascular resistance. This pharmacodynamic interaction can blunt the antihypertensive efficacy of pirfenidone, potentially leading to inadequate blood pressure control in patients with pulmonary fibrosis and concurrent hypertension. Clinically, this may necessitate dose adjustments or alternative therapies to maintain optimal cardiovascular outcomes."
Common clinical questions about ESBRIET vs PIRFENIDONE, answered by our medical review team.
ESBRIET is a Antifibrotic that works by Pirfenidone inhibits TGF-β stimulated collagen production and reduces fibroblast proliferation, exhibiting anti-inflammatory and antifibrotic effects in pulmonary fibrosis.. PIRFENIDONE is a Antifibrotic Agent that works by Pirfenidone is a pyridone derivative that inhibits TGF-β1-mediated collagen synthesis, reduces fibroblast proliferation, and downregulates the production of pro-inflammatory cytokines (e.g., TNF-α, IL-1β) and growth factors. Its exact mechanism in idiopathic pulmonary fibrosis (IPF) is not fully elucidated, but it is thought to exert antifibrotic and anti-inflammatory effects.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ESBRIET and PIRFENIDONE depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of ESBRIET is: 801 mg three times daily orally with food.. The standard adult dose of PIRFENIDONE is: 801 mg orally three times daily with food, total daily dose 2403 mg. Starting dose: 267 mg three times daily for first 7 days, then 534 mg three times daily for 7 days, then maintenance 801 mg three times daily.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between ESBRIET and PIRFENIDONE in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. ESBRIET is classified as Category C. Pirfenidone is teratogenic in animal studies, causing fetal malformations and embryotoxicity at clinically relevant exposures. There are no adequate human studies. Use during pregn. PIRFENIDONE is classified as Category C. Pirfenidone is classified as FDA Pregnancy Category C. In animal studies, it caused fetal toxicity (reduced fetal weight, increased skeletal variations) at doses below human exposu. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.