Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
AFATINIB vs AGRYLIN
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Afatinib is an irreversible, covalent-binding inhibitor of the Erb B family of tyrosine kinases, including EGFR (Erb B1), HER2 (Erb B2), Erb B3, and Erb B4. It blocks downstream signaling pathways such as PI3K/AKT and MAPK, leading to inhibition of tumor cell proliferation and survival.
Agrylin (anagrelide) inhibits cyclic nucleotide phosphodiesterase III (PDE3) and reduces platelet production by interfering with megakaryocyte maturation and proliferation, likely via inhibition of cyclic AMP phosphodiesterase and modulation of intracellular calcium levels.
First-line treatment of metastatic non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) exon 19 deletions or exon 21 (L858R) substitution mutations,Treatment of metastatic squamous NSCLC progressing after platinum-based chemotherapy,Off-label: Use in other EGFR-mutant cancers (e.g., head and neck cancer, colorectal cancer) with specific mutations
Essential thrombocythemia (ET) to reduce elevated platelet counts and the risk of thrombotic complications
40 mg orally once daily, continuously.
Adults: 0.5 mg orally once or twice daily, increased by 0.5 mg every 2 weeks to maintain platelet count <600,000/µL. Maximum dose: 10 mg/day.
Terminal half-life is approximately 37 hours; supports once-daily dosing with steady-state achieved within 8 days.
Terminal elimination half-life: 1.3–1.5 days (31–36 hours) in patients with ET; allows twice-daily dosing.
Primarily metabolized by CYP3A4 and to a lesser extent by CYP3A4-independent pathways including flavin-containing monooxygenase (FMO). Excretion mainly via feces (85%) and urine (4%) as unchanged drug and metabolites.
Primarily metabolized by CYP1A2 to the active metabolite 3-hydroxyanagrelide, and to a lesser extent by CYP2C19 and CYP2D6.
Primarily fecal (85%) as unchanged drug and metabolites; renal excretion accounts for <4% of the dose.
Renal: 80% (primarily unchanged drug), Biliary/Fecal: 5%
Approximately 95% bound to plasma proteins, primarily to albumin.
82–88% bound to plasma proteins (primarily albumin).
Volume of distribution is approximately 2300 L (about 33 L/kg for a 70 kg individual), indicating extensive tissue distribution.
30–36 L (approximately 0.45–0.5 L/kg for a 70 kg adult); indicates extensive tissue distribution.
Oral bioavailability is approximately 92% relative to an oral solution; food reduces exposure, so take on an empty stomach.
Oral: 65–80% (median 73%)
No starting dose adjustment required for mild to moderate renal impairment (Cr Cl ≥30 m L/min). Not recommended for severe renal impairment (Cr Cl <30 m L/min) due to safety concerns.
No specific GFR-based recommendations; use with caution in renal impairment (Cr Cl <50 m L/min) and monitor closely.
Child-Pugh A: 40 mg once daily. Child-Pugh B: Reduce dose to 30 mg once daily. Child-Pugh C: Not recommended due to lack of data.
Child-Pugh A: No adjustment. Child-Pugh B or C: Reduce initial dose by 50% and titrate cautiously.
Safety and efficacy not established in pediatric patients; no specific dosing recommendations.
Children ≥7 years: 0.5 mg orally once or twice daily; adjust based on platelet response. Maximum: 10 mg/day. Not established for <7 years.
No specific dose adjustment recommended based on age alone; monitor renal function and tolerability, as elderly patients may have decreased renal function or comorbidities.
No specific adjustment; start at lower end of dosing range (0.5 mg twice daily) and monitor renal function and platelet counts closely.
None.
None
Severe diarrhea (including dehydration and acute kidney injury),Interstitial lung disease (ILD)/pneumonitis,Severe hepatotoxicity (elevated liver enzymes, hepatitis),Left ventricular dysfunction (assess LVEF at baseline and during treatment),Severe bullous, blistering, and exfoliative skin reactions (e.g., Stevens-Johnson syndrome),Gastrointestinal perforation,Ocular toxicities (keratitis, conjunctivitis),Renal toxicity (proteinuria, nephrotic syndrome),Fetal harm (embryo-fetal toxicity),Drug interactions with CYP3A4 inducers or inhibitors
Cardiovascular risks: increased risk of ventricular tachycardia, QTc prolongation, and heart failure; use caution in patients with known cardiac disease.,Hematologic effects: monitor complete blood counts regularly due to risk of anemia, leukopenia, or thrombocytopenia.,Hepatic impairment: reduce dose in patients with moderate to severe hepatic impairment.,Renal impairment: use with caution in severe renal impairment.
None reported,Relative contraindications: pre-existing severe hepatic impairment, severe renal impairment, pregnancy, and breastfeeding
Severe hepatic impairment,Known hypersensitivity to anagrelide or any component of the formulation
Take on an empty stomach (at least 1 hour before or 2 hours after food). Avoid grapefruit, grapefruit juice, and Seville oranges as they may alter drug metabolism. High-fat meals reduce absorption.
Grapefruit and grapefruit juice should be avoided as they may increase anagrelide plasma concentrations. No other specific dietary restrictions; however, maintain adequate hydration to reduce risk of crystalluria.
Afatinib is classified as Pregnancy Category D. First trimester exposure is associated with increased risk of major congenital malformations, including cardiac, skeletal, and neural tube defects based on animal studies showing embryotoxicity and teratogenicity at doses below human exposure. Second and third trimester exposure may cause fetal growth restriction, oligohydramnios, and impaired renal function due to inhibition of EGFR signaling critical for fetal development.
Pregnancy Category C. Anagrelide is not recommended in pregnancy. Animal studies have shown embryotoxicity and teratogenicity (e.g., increased fetal resorptions, skeletal anomalies) at doses less than the human therapeutic dose. There are no adequate and well-controlled studies in pregnant women. Use only if potential benefit justifies potential risk to fetus. First trimester: Avoid due to organogenesis risk. Second and third trimesters: Unknown risks; consider alternative therapy.
No human data on afatinib excretion in breast milk; however, animal studies indicate drug presence in milk. M/P ratio is unknown. Due to potential for serious adverse effects in breastfed infants, breastfeeding is contraindicated during therapy and for at least 2 weeks after the last dose.
It is not known whether anagrelide is excreted in human milk. No M/P ratio is available. Due to potential for serious adverse reactions in breastfed infants (e.g., thrombocytopenia, cardiovascular effects), advise women not to breastfeed during treatment and for at least 7 days after last dose.
No specific dosing guidelines for pregnancy. Pharmacokinetic changes (increased volume of distribution, altered metabolism) may occur but studies have not established dose adjustments. The drug should be avoided in pregnancy unless benefit outweighs risk; if used, consider therapeutic drug monitoring if available.
No specific pharmacokinetic studies in pregnancy. Pregnancy-induced plasma volume expansion may lower drug concentrations, potentially requiring dose adjustment to maintain therapeutic effect. However, due to teratogenicity risks, avoid use in pregnancy. If necessary, start at lowest effective dose (0.5 mg/day) and titrate based on platelet count monitoring, not to exceed 10 mg/day.
Monitor for diarrhea, which can be severe; consider loperamide and hydration. Assess for interstitial lung disease (ILD) and hepatotoxicity. Dose reduction required for severe renal impairment (Cr Cl 15–29 m L/min). For patients with EGFR exon 19 deletion or exon 21 L858R mutation, first-line use improves PFS. Avoid P-glycoprotein strong inducers (e.g., rifampin) during treatment.
Agrylin (anagrelide) is a phosphodiesterase III inhibitor used to reduce platelet counts in essential thrombocythemia. Monitor platelet count weekly during titration; target <600,000/µL. Avoid in patients with severe hepatic impairment (Child-Pugh C). Use with caution in cardiac disease due to risk of QT prolongation and arrhythmias. Anagrelide may increase bleeding risk, especially when combined with anticoagulants or NSAIDs. Discontinue 4-5 days before elective surgery.
Take afatinib at least 1 hour before or 2 hours after a meal.,Do not crush, chew, or split tablets; swallow whole with water.,Seek medical help for severe or persistent diarrhea, cough, or difficulty breathing.,Avoid grapefruit and Seville oranges during treatment.,Report signs of liver problems (yellowing skin/eyes, dark urine).,Use effective contraception during and for 2 weeks after stopping therapy.,Avoid direct sunlight exposure; use sunscreen.
Take exactly as prescribed; do not skip doses or double up.,Report any signs of bleeding (easy bruising, nosebleeds, black/tarry stools) or palpitations immediately.,Avoid NSAIDs like ibuprofen and aspirin unless directed by your doctor.,Do not consume grapefruit or grapefruit juice while taking this medication.,Inform all healthcare providers (including dentists) that you are on anagrelide.,Store at room temperature away from moisture and heat.
"Afatinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, and fluvoxamine, a selective serotonin reuptake inhibitor (SSRI), both undergo metabolism via CYP450 enzymes. Afatinib is a moderate inhibitor of CYP2D6 and may also inhibit CYP1A2 and CYP3A4, while fluvoxamine is a known inhibitor of CYP1A2 and CYP2C19. Coadministration can lead to increased fluvoxamine concentrations due to inhibition of its metabolism, potentially resulting in enhanced serotonergic effects such as serotonin syndrome, as well as increased adverse effects like nausea, dizziness, or QT prolongation."
"The combination of afatinib, a tyrosine kinase inhibitor, with pantoprazole, a proton pump inhibitor (PPI), can lead to reduced absorption of afatinib due to elevated gastric pH. Afatinib exhibits pH-dependent solubility, and higher gastric pH decreases its dissolution and bioavailability, potentially reducing its therapeutic efficacy. This interaction may result in suboptimal plasma concentrations of afatinib, increasing the risk of treatment failure in patients with non-small cell lung cancer."
"Estrone, an estrogen hormone, may induce the expression of UDP-glucuronosyltransferase (UGT) enzymes, which are involved in the glucuronidation and subsequent clearance of afatinib. This induction can lead to a decrease in afatinib serum concentrations, potentially reducing its efficacy in the treatment of non-small cell lung cancer. Clinically, this interaction may result in suboptimal therapeutic outcomes unless the afatinib dose is adjusted."
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about AFATINIB vs AGRYLIN, answered by our medical review team.
AFATINIB is a Tyrosine Kinase Inhibitor Antineoplastic that works by Afatinib is an irreversible, covalent-binding inhibitor of the Erb B family of tyrosine kinases, including EGFR (Erb B1), HER2 (Erb B2), Erb B3, and Erb B4. It blocks downstream signaling pathways such as PI3K/AKT and MAPK, leading to inhibition of tumor cell proliferation and survival.. AGRYLIN is a Antineoplastic Agent that works by Agrylin (anagrelide) inhibits cyclic nucleotide phosphodiesterase III (PDE3) and reduces platelet production by interfering with megakaryocyte maturation and proliferation, likely via inhibition of cyclic AMP phosphodiesterase and modulation of intracellular calcium levels.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between AFATINIB and AGRYLIN 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 AFATINIB is: 40 mg orally once daily, continuously.. The standard adult dose of AGRYLIN is: Adults: 0.5 mg orally once or twice daily, increased by 0.5 mg every 2 weeks to maintain platelet count <600,000/µL. Maximum dose: 10 mg/day.. 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 AFATINIB and AGRYLIN 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. AFATINIB is classified as Category C. Afatinib is classified as Pregnancy Category D. First trimester exposure is associated with increased risk of major congenital malformations, including cardiac, skeletal, and neura. AGRYLIN is classified as Category C. Pregnancy Category C. Anagrelide is not recommended in pregnancy. Animal studies have shown embryotoxicity and teratogenicity (e.g., increased fetal resorptions, skeletal anomalies. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.