Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
MEXATE-AQ vs CLOLAR
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.
Clolar (clofarabine) is a purine nucleoside antimetabolite that inhibits DNA synthesis and RNA transcription. It is phosphorylated intracellularly to its active triphosphate form, which competes with adenosine triphosphate for incorporation into DNA, leading to chain termination and inhibition of DNA polymerase and ribonucleotide reductase, resulting in 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).
FDA: 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), chronic myeloid leukemia (CML) in blast crisis.
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.
5 mg/m2 intravenously over 2 hours daily for 5 consecutive days. Repeat 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 approximately 5.2 hours in patients with normal renal function; prolonged in renal impairment (up to 9.8 hours with Cr Cl <60 m L/min) and in elderly; clinical context: supports once-daily dosing adjustment for renal function.
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.
Clofarabine is partially metabolized by deamination via cytidine deaminase (CDA) to inactive 6-keto-clofarabine. Approximately 50-60% of the drug is excreted unchanged in urine.
Renal excretion predominates (80-90% as unchanged drug) via glomerular filtration and active tubular secretion. Biliary/fecal elimination is minor (<10%).
Renal: 50-60% as unchanged drug; biliary/fecal: minimal (<5%)
Approximately 50–60% bound primarily to albumin. Weakly bound and readily displaceable by other drugs.
47% bound to human 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.
Central Vd approximately 172 L/m² (extensive tissue distribution); in L/kg: ~4.6 L/kg (assuming 70 kg patient with BSA 1.73 m²). Clinical meaning: indicates wide distribution into total body water and tissues, exceeding total body water.
Oral: 30–60% (dose-dependent; saturable absorption at high doses). Intramuscular: 80–100%. Subcutaneous: approximately 90%.
Intravenous: 100% (only route of administration); oral: not available (no oral formulation).
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.
Cr Cl >= 60 m L/min: no adjustment. Cr Cl 30-59 m L/min: reduce dose by 20%. Cr Cl < 30 m L/min: contraindicated.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated.
No specific guidelines; use caution in severe hepatic impairment (Child-Pugh class C) and consider dose reduction based on tolerability.
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.
1-21 years: 5 mg/m2 IV over 2 hours daily for 5 days every 28 days; reduce dose by 50% in patients with renal impairment.
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, but monitor renal function closely due to age-related decline and increased risk of toxicity.
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.
WARNING: HEMATOLOGIC TOXICITY, INFECTION, AND HEPATIC TOXICITY. Clolar suppresses bone marrow function, causing severe neutropenia, thrombocytopenia, and anemia. Fatal infections have occurred. Hepatic toxicity, including hepatic failure and death, has been reported. Monitor blood counts and liver function frequently.
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.
Bone marrow suppression: severe neutropenia, thrombocytopenia, and anemia require close monitoring. Infections: serious and fatal infections (bacterial, fungal, viral) may occur. Hepatic toxicity: elevation of liver enzymes, bilirubin, and hepatic veno-occlusive disease. Renal toxicity: increased creatinine, hematuria, and hemolytic uremic syndrome-like reactions. Cardiac toxicity: pericardial effusion, hypotension, and ventricular dysfunction. Tumor lysis syndrome. Hypersensitivity reactions. Use in pregnancy: embryo-fetal toxicity. Vaccination: avoid live vaccines.
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.
Absolute: Hypersensitivity to clofarabine or any component of the formulation. Relative: Severe hepatic impairment (bilirubin >3 mg/d L or transaminases >5x ULN). 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.
No specific food interactions are documented. However, maintain adequate hydration to reduce risk of nephrotoxicity and tumor lysis syndrome. Avoid grapefruit and grapefruit juice as they may affect metabolism via CYP3A4 (theoretical concern, though clofarabine is primarily renally excreted).
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 contraindicated in pregnancy. Based on its mechanism of action (inhibitor of DNA synthesis) and animal studies, there is a high risk of fetal harm if administered during pregnancy. In the first trimester, there is a significant risk of embryolethality and teratogenicity (structural anomalies). In the second and third trimesters, fetal growth restriction and central nervous system damage may occur. Pregnancy must be excluded before initiation.
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.
No data available on the excretion of clofarabine into breast milk or its effects on the nursing infant. Due to potential for serious adverse reactions (e.g., myelosuppression, gastrointestinal toxicity), breastfeeding is contraindicated during therapy and for at least 3 months after the last dose. M/P ratio is unknown.
Contraindicated in pregnancy; no dose adjustment recommended due to teratogenicity. In lactating females, discontinue breastfeeding or avoid use.
There are no established dose adjustments for clofarabine during pregnancy, as use is contraindicated. Physiological changes in pregnancy (e.g., increased plasma volume, altered renal clearance) may affect pharmacokinetics, but no dosing guidelines exist. If inadvertent exposure occurs, immediate discontinuation is recommended and the pregnancy should be managed by a maternal-fetal medicine specialist.
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.
Clolar (clofarabine) is a purine nucleoside analog indicated for pediatric relapsed/refractory acute lymphoblastic leukemia. Key pearls: (1) Monitor for systemic inflammatory response syndrome (SIRS) and capillary leak syndrome; premedicate with corticosteroids. (2) Requires aggressive hydration and allopurinol for tumor lysis prophylaxis. (3) Dose reductions needed for renal impairment (Cr Cl < 60 m L/min). (4) Avoid live vaccines during and after treatment.
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.
Clolar is a chemotherapy drug used to treat a type of leukemia in children that has not responded to other treatments.,You may experience side effects like fever, nausea, vomiting, diarrhea, and skin rashes. Report any signs of infection or unusual bleeding.,Drink plenty of fluids as directed to prevent kidney problems. You may receive IV fluids before and after treatment.,Avoid vaccinations without doctor approval, as live vaccines are not safe during treatment.,This drug can cause severe reactions including organ inflammation and fluid retention; seek immediate medical help if you have difficulty breathing, rapid weight gain, or swelling.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about MEXATE-AQ vs CLOLAR, 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.. CLOLAR is a Antineoplastic Agent that works by Clolar (clofarabine) is a purine nucleoside antimetabolite that inhibits DNA synthesis and RNA transcription. It is phosphorylated intracellularly to its active triphosphate form, which competes with adenosine triphosphate for incorporation into DNA, leading to chain termination and inhibition of DNA polymerase and ribonucleotide reductase, resulting in apoptosis.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between MEXATE-AQ and CLOLAR 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 CLOLAR is: 5 mg/m2 intravenously over 2 hours daily for 5 consecutive days. Repeat 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 CLOLAR 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 . CLOLAR is classified as Category C. Clofarabine is contraindicated in pregnancy. Based on its mechanism of action (inhibitor of DNA synthesis) and animal studies, there is a high risk of fetal harm if administered du. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.