Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
MEXATE-AQ vs CLOFARABINE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Methotrexate is a folate analog that inhibits dihydrofolate reductase (DHFR), blocking the conversion of dihydrofolate to tetrahydrofolate, which is required for the synthesis of purines and pyrimidines. This leads to inhibition of DNA, RNA, and protein synthesis, particularly in rapidly dividing cells. It also has immunosuppressive effects via inhibition of T cell activation and reduction of inflammatory cytokines.
Clofarabine is a purine nucleoside antimetabolite that inhibits DNA synthesis by reducing intracellular deoxynucleotide triphosphate pools via inhibition of ribonucleotide reductase, and by terminating DNA chain elongation through incorporation into DNA, leading to apoptosis.
FDA-approved: Chemotherapy for gestational choriocarcinoma, chorioadenoma destruens, hydatidiform mole, acute lymphocytic leukemia, meningeal leukemia, breast cancer, head and neck cancer, cutaneous T-cell lymphoma, lung cancer, non-Hodgkin's lymphoma, osteosarcoma, and mycosis fungoides.,FDA-approved: Severe, active rheumatoid arthritis (RA) in adults who have failed first-line therapy.,FDA-approved: Pediatric patients with polyarticular juvenile idiopathic arthritis (p JIA) who have failed first-line therapy.,FDA-approved: Psoriasis (severe, recalcitrant) in adults.,Off-label: Prevention of graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation.,Off-label: Crohn's disease (maintenance of remission in steroid-dependent patients).,Off-label: Ectopic pregnancy (medical management).
Treatment of relapsed or refractory acute lymphoblastic leukemia (ALL) in pediatric patients aged 1 to 21 years,Off-label: Treatment of acute myeloid leukemia (AML), myelodysplastic syndromes (MDS)
Methotrexate: 7.5-25 mg orally once weekly for rheumatoid arthritis; 30-40 mg/m2 IV weekly for mycosis fungoides; 50-75 mg/m2 IV over 4-6 hours weekly for osteosarcoma; 15-20 mg/m2 IM weekly for psoriasis.
52 mg/m^2 intravenously over 2 hours daily for 5 consecutive days, repeated every 28 days.
Terminal elimination half-life is approximately 3–10 hours for low doses (<30 mg/m²) and 8–15 hours for high doses (>80 mg/m²). Prolonged to 48–72 hours in patients with third-space effusions or renal impairment.
Terminal elimination half-life: 5.2 hours (range 4-6 hours) in adult patients; clinically, this supports a 5-day continuous infusion schedule
Metabolized primarily in the liver to polyglutamates (which are active metabolites) via folylpolyglutamate synthetase. Partial metabolism via aldehyde oxidase and xanthine oxidase to 7-hydroxymethotrexate. Methotrexate is also partially metabolized by intestinal flora. Elimination is primarily renal via glomerular filtration and active tubular secretion.
Hepatic; primarily metabolized by deamination via cytidine deaminase to 6-ketoclofarabine, a major metabolite. Also undergoes phosphorylation intracellularly. CYP450 involvement is minimal.
Renal excretion predominates (80-90% as unchanged drug) via glomerular filtration and active tubular secretion. Biliary/fecal elimination is minor (<10%).
Renal: 49-60% as unchanged drug; biliary/fecal: minimal (<1%)
Approximately 50–60% bound primarily to albumin. Weakly bound and readily displaceable by other drugs.
47% bound to plasma proteins (primarily albumin)
Vd: 0.4–0.8 L/kg (initial 0.18 L/kg, steady-state 0.4–0.8 L/kg). Distributes into third-space fluids (pleural, ascitic), leading to prolonged elimination.
Vd: 14.6 L/kg (range 10-20 L/kg); indicates extensive extravascular distribution and tissue binding
Oral: 30–60% (dose-dependent; saturable absorption at high doses). Intramuscular: 80–100%. Subcutaneous: approximately 90%.
IV: 100% (only IV route); oral: not approved
For GFR 40-59 m L/min: reduce dose by 20%; GFR 20-39 m L/min: reduce dose by 40%; GFR <20 m L/min: contraindicated.
Clcr ≥ 60 m L/min: no adjustment; Clcr 30-59 m L/min: reduce dose to 39 mg/m^2; Clcr < 30 m L/min: not recommended (no data).
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 25% (monitor toxicity); Child-Pugh C: not recommended (no data).
For acute lymphoblastic leukemia (ALL): 15-20 mg/m2 IM once weekly as maintenance; for osteosarcoma: 12 g/m2 IV over 4 hours with leucovorin rescue.
52 mg/m^2 intravenously over 2 hours daily for 5 days every 28 days (same as adult dosing per body surface area; safety and efficacy established in pediatric patients 1 year and older).
Start at lowest recommended dose (e.g., 5 mg orally once weekly) with careful monitoring for renal function, hepatic function, and folate levels; adjust based on tolerance.
No specific dose adjustment based solely on age; monitor renal function closely due to increased risk of nephrotoxicity; use same dosing as adults with renal adjustment as per GFR.
Boxed Warning: Methotrexate can cause fetal death or teratogenic effects when administered to pregnant women. It is contraindicated in pregnant women with psoriasis or RA. It also has a boxed warning for severe toxicity and death due to inadvertent daily (as opposed to weekly) dosing; hepatic toxicity, including acute hepatitis and chronic hepatic fibrosis; myelosuppression, including severe bone marrow suppression; and pulmonary toxicity, including acute or chronic interstitial pneumonitis. Additionally, anaphylactic reactions can occur. For patients with psoriasis, methotrexate should be used only for severe, recalcitrant cases unresponsive to other therapy.
Clofarabine causes severe bone marrow suppression, including neutropenia, anemia, thrombocytopenia, and increased risk of infection. Hemorrhage and severe infections have been reported. Monitor blood counts regularly.
Fatal toxicities (including hematologic, hepatic, pulmonary, renal, dermatologic, and GI) can occur with methotrexate; monitor closely.,Hepatic toxicity: Monitor liver function tests; avoid or use with caution in patients with active liver disease or alcohol abuse.,Pulmonary toxicity: Acute or chronic interstitial pneumonitis may occur; monitor for cough, fever, dyspnea, and hypoxia.,Myelosuppression: Monitor CBC and platelet counts regularly; severe pancytopenia can occur.,Renal toxicity: Adequate renal function is essential; avoid NSAIDs, salicylates, and other nephrotoxic drugs if possible.,Gastrointestinal toxicity: Mucositis, ulcerative stomatitis, diarrhea, and hemorrhagic enteritis may occur.,Dermatologic toxicity: Phototoxicity, radiation recall, and severe skin reactions (including Stevens-Johnson syndrome) can occur.,Immunosuppression: Increased risk of infections, including opportunistic infections; avoid live vaccines.,Carcinogenicity: Increased risk of lymphoproliferative disorders (may be reversible with discontinuation).,Concomitant use with proton pump inhibitors (PPIs) may increase methotrexate levels.
1) Myelosuppression: monitor CBCs; dose adjustment may be needed. 2) Infections: increased susceptibility. 3) Hemorrhagic cystitis: may occur; manage with hydration and monitoring. 4) Hepatic toxicity: monitor liver function tests; dose reduction in hepatic impairment. 5) Renal toxicity: monitor renal function; dose adjustment for creatinine clearance <60 m L/min. 6) Tumor lysis syndrome: hydrate and use prophylactic allopurinol. 7) Systemic inflammatory response syndrome (SIRS): monitor for signs; discontinue if occurs.
Hypersensitivity to methotrexate or any component of the formulation.,Pregnancy and breastfeeding (due to risk of fetal death/teratogenicity and excretion in breast milk).,Patients with psoriasis or RA who have alcoholism, alcoholic liver disease, chronic liver disease, or overt immunodeficiency.,Pre-existing blood dyscrasias (severe anemia, leukopenia, neutropenia, thrombocytopenia).,Concomitant use with live vaccines.
Hypersensitivity to clofarabine or any component of the formulation; severe hepatic impairment (Child-Pugh class C); severe renal impairment (creatinine clearance <30 m L/min).
Avoid folic acid-rich foods (leafy greens, fortified grains) in large amounts during methotrexate therapy as they may reduce efficacy. No specific food-drug interactions; maintain a well-balanced diet.
Grapefruit and grapefruit juice may affect liver enzymes and should be avoided. No specific food restrictions, but avoid alcohol due to potential hepatotoxicity. Maintain adequate hydration; no other known food interactions.
FDA Pregnancy Category X. First trimester: High risk of miscarriage, CNS defects, craniofacial anomalies. Second trimester: IUGR, skeletal abnormalities. Third trimester: Neonatal bone marrow suppression, immunosuppression.
Clofarabine is embryotoxic and teratogenic in animal studies. In humans, it is classified as Pregnancy Category D. First trimester exposure is associated with major congenital malformations including neural tube defects, skeletal anomalies, and cardiovascular defects. Second and third trimester exposure may cause fetal myelosuppression, intrauterine growth restriction, and premature delivery.
Contraindicated. Methotrexate is excreted in breast milk; accumulation may occur in nursing infants due to immature renal function. M/P ratio not established; theoretical risk of serious adverse effects.
It is unknown whether clofarabine is excreted in human breast milk. Due to the potential for serious adverse reactions in nursing infants, breastfeeding is contraindicated during therapy and for at least 1 week after the last dose. M/P ratio is not available.
Contraindicated in pregnancy; no dose adjustment recommended due to teratogenicity. In lactating females, discontinue breastfeeding or avoid use.
No specific pharmacokinetic studies have been conducted in pregnant women. Dose adjustments based on pregnancy-induced physiologic changes (increased plasma volume, renal clearance) are not established. Use with caution; the lowest effective dose based on tolerability and clinical response is recommended. Close monitoring for toxicity is essential.
Mexate-AQ (methotrexate) requires folic acid supplementation to reduce gastrointestinal and hematologic toxicity. Administer leucovorin rescue after high-dose therapy. Avoid NSAIDs, salicylates, and sulfonamides due to increased methotrexate toxicity. Monitor renal function, liver enzymes, and blood counts regularly. Contraindicated in pregnancy, breastfeeding, and active infections.
Clofarabine is a purine nucleoside antimetabolite used primarily in pediatric relapsed or refractory acute lymphoblastic leukemia (ALL). It is associated with significant myelosuppression; monitor absolute neutrophil count and platelets closely. Capillary leak syndrome and systemic inflammatory response syndrome (SIRS) are rare but serious adverse effects; consider prophylactic corticosteroids. Hepatic veno-occlusive disease (VOD) has been reported, especially in patients with prior stem cell transplant. Administer with adequate hydration and monitor for tumor lysis syndrome.
Take exactly as prescribed; do not change dose without consulting your doctor.,Avoid alcohol completely while on this medication.,Report any signs of infection (fever, sore throat), unusual bleeding, or mouth ulcers immediately.,Use effective contraception during treatment and for at least 3 months after stopping.,Do not take any over-the-counter medications, especially NSAIDs (ibuprofen, naproxen), without permission.,Drink plenty of fluids to prevent kidney damage.,Attend all scheduled blood tests and appointments.,Capsules should be swallowed whole; do not crush or chew.
Clofarabine is a chemotherapy drug that may lower your blood cell counts, increasing risk of infection, bleeding, and fatigue.,Report any signs of infection (fever, chills, sore throat), unusual bleeding or bruising, or shortness of breath immediately.,Drink plenty of fluids (8-10 glasses per day) to prevent kidney problems and tumor lysis syndrome.,Avoid live vaccines and close contact with people who have recently received oral polio vaccine.,Use effective contraception during treatment and for at least 6 months after the last dose.,Do not breastfeed while taking clofarabine.,You may experience nausea, vomiting, or diarrhea; your doctor can prescribe medications to manage these symptoms.
No interactions on record
"Clofarabine, a purine nucleoside antimetabolite used in hematologic malignancies, may reduce the metabolism of Eltrombopag, a thrombopoietin receptor agonist, via inhibition of UDP-glucuronosyltransferase (UGT) enzymes, particularly UGT1A1 and UGT1A3. This leads to increased systemic exposure of Eltrombopag, potentially elevating the risk of hepatotoxicity (e.g., elevated liver enzymes) and other adverse effects such as thrombosis. Clinical outcomes may include exacerbated liver injury, which is particularly concerning in patients with pre-existing hepatic impairment or those receiving other hepatotoxic agents."
"Concurrent use of clofarabine and mecamylamine may synergistically increase the risk of severe hypotension and syncope. Clofarabine is a purine nucleoside analog that can cause capillary leak syndrome and hypotension, while mecamylamine is a ganglionic blocker that inhibits sympathetic outflow, leading to orthostatic hypotension. The combined hypotensive effects may result in profound blood pressure reduction, dizziness, and potential falls, particularly in patients with impaired cardiovascular function."
"The combination of clofarabine and nifedipine may increase the risk of cardiotoxicity, particularly QT interval prolongation and left ventricular dysfunction. Clofarabine has been associated with pericardial effusion and cardiac tamponade, while nifedipine, a calcium channel blocker, can cause hypotension and reflex tachycardia, potentially compounding hemodynamic stress in patients with compromised cardiac function. Clinical outcomes may include arrhythmias, heart failure exacerbation, or sudden cardiac death, especially in patients with preexisting cardiovascular risk factors."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about MEXATE-AQ vs CLOFARABINE, answered by our medical review team.
MEXATE-AQ is a Antineoplastic Agent that works by Methotrexate is a folate analog that inhibits dihydrofolate reductase (DHFR), blocking the conversion of dihydrofolate to tetrahydrofolate, which is required for the synthesis of purines and pyrimidines. This leads to inhibition of DNA, RNA, and protein synthesis, particularly in rapidly dividing cells. It also has immunosuppressive effects via inhibition of T cell activation and reduction of inflammatory cytokines.. CLOFARABINE is a Antineoplastic Agent that works by Clofarabine is a purine nucleoside antimetabolite that inhibits DNA synthesis by reducing intracellular deoxynucleotide triphosphate pools via inhibition of ribonucleotide reductase, and by terminating DNA chain elongation through incorporation into DNA, leading to apoptosis.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between MEXATE-AQ and CLOFARABINE depend on the specific clinical indication. These are both Antineoplastic Agent agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of MEXATE-AQ is: Methotrexate: 7.5-25 mg orally once weekly for rheumatoid arthritis; 30-40 mg/m2 IV weekly for mycosis fungoides; 50-75 mg/m2 IV over 4-6 hours weekly for osteosarcoma; 15-20 mg/m2 IM weekly for psoriasis.. The standard adult dose of CLOFARABINE is: 52 mg/m^2 intravenously over 2 hours daily for 5 consecutive days, repeated every 28 days.. 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 MEXATE-AQ and CLOFARABINE 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. MEXATE-AQ is classified as Category C. FDA Pregnancy Category X. First trimester: High risk of miscarriage, CNS defects, craniofacial anomalies. Second trimester: IUGR, skeletal abnormalities. Third trimester: Neonatal . CLOFARABINE is classified as Category C. Clofarabine is embryotoxic and teratogenic in animal studies. In humans, it is classified as Pregnancy Category D. First trimester exposure is associated with major congenital malf. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.