Methotrexate Drug Information

Important Dosage and Safety Information

Verify pregnancy status in females of reproductive potential before starting methotrexate tablets. Instruct patients and caregivers to take the recommended dosage as directed, because medication errors have led to deaths. When switching the dosing regimen from oral administration to intravenous, intramuscular, or subcutaneous administration, an alternative dosing regimen may be necessary.

Do not administer to patients who are unable to swallow a tablet. Methotrexate tablets are a cytotoxic drug. Follow applicable special handling and disposal procedures. 1

Recommended Dosage for Neoplastic Diseases Acute Lymphoblastic Leukemia The recommended starting dosage of methotrexate tablets is 20 mg/m 2 orally once weekly, as part of a combination chemotherapy maintenance regimen. After initiating methotrexate tablets, periodically monitor absolute neutrophil count (ANC) and platelet count and adjust the dose to maintain ANC at a desirable level and for excessive myelosuppression. Mycosis Fungoides The recommended dosage of methotrexate tablets is 25 to 75 mg orally once weekly when administered as a single agent or 10 mg/m 2 orally twice weekly as part of a combination chemotherapy regimen.

Relapsed or Refractory Non-Hodgkin Lymphomas The recommended dosage of methotrexate tablets is 2.5 mg orally 2 to 4 times per week (maximum 10 mg per week) as part of a metronomic combination chemotherapy regimen.

Recommended Dosage for Rheumatoid Arthritis

The recommended starting dosage of methotrexate tablets is 7.5 mg orally once weekly with escalation to achieve optimal response. Dosages of more than 20 mg once weekly result in an increased risk of serious adverse reactions, including myelosuppression. When responses are observed, the majority occurred between 3 and 6 weeks from initiation of treatment; however, responses have occurred up to 12 weeks after treatment initiation.

Administer folic acid or folinic acid to reduce the risk of methotrexate adverse reactions.

Recommended Dosage for Psoriasis

The recommended dosage of methotrexate tablets is 10 to 25 mg orally once weekly until an adequate response is achieved. Adjust the dose gradually to achieve optimal clinical response; do not exceed a dose of 30 mg per week. Once optimal clinical response has been achieved, reduce the dosage to the lowest possible dosing regimen.

Dosage Modifications for Adverse Reactions

Discontinue methotrexate tablets for: • Anaphylaxis or other severe hypersensitivity reactions • Lymphoproliferative disease Withhold, dose reduce or discontinue methotrexate tablets as appropriate for: • Myelosuppression Withhold or discontinue methotrexate tablets as appropriate for: • Severe gastrointestinal toxicity • Hepatotoxicity • Pulmonary toxicity • Severe dermatologic reactions • Severe renal toxicity • Serious infections • Neurotoxicity

Clinical Trials Experience

Because clinical trials and other studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Common adverse reactions were: ulcerative stomatitis, leukopenia, nausea, and abdominal distress. Other clinically relevant adverse reactions were infection, malaise, fatigue, chills, fever, and dizziness.

Rheumatoid Arthritis The most common adverse reactions of methotrexate that exceeded the rate of placebo in 12- to 18-week double-blind studies in patients (n=128) with rheumatoid arthritis are listed below. Patients received methotrexate 7.5 to 15 mg orally once weekly. Most patients received concomitant nonsteroidal anti-inflammatory drugs (NSAIDs) and some also received corticosteroids.

Hepatic histology was not examined in these short-term studies. Psoriasis In two published series of adults with psoriasis (n=204, 248) who received methotrexate up to 25 mg per week for up to 4 years, adverse reaction rates were similar to those in patients with rheumatoid arthritis, except for alopecia, photosensitivity, and “burning of skin lesions” (3% to 10% each). Painful plaque erosions have been reported.

Postmarketing Experience

The following adverse reactions have been identified during postapproval use of methotrexate. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Cardiovascular: Thromboembolic events (including arterial thrombosis, cerebral thrombosis, deep vein thrombosis, retinal vein thrombosis, thrombophlebitis, and pulmonary embolus), pericarditis, pericardial effusion, hypotension, sudden death Endocrine: Diabetes Eye: Optic neuropathy, blurred vision, ocular pain, conjunctivitis, xerophthalmia Gastrointestinal: Hemorrhagic enteritis, intestinal perforation, gingivitis, pancreatitis, pharyngitis, hematemesis, melena, gastrointestinal ulceration Hematology: Aplastic anemia, lymphadenopathy, hypogammaglobulinemia Hepatobiliary: Acute hepatitis, decreased serum albumin, fibrosis, cirrhosis Immune system: Anaphylaxis, anaphylactoid reactions, vasculitis Metabolism: Hyperglycemia Musculoskeletal: Stress fracture, soft tissue and bone necrosis, arthralgia, myalgia, osteoporosis Nervous system: Headaches, drowsiness, blurred vision, speech impairment (including dysarthria and aphasia), transient cognitive dysfunction, mood alteration, unusual cranial sensations, paresis, encephalopathy, and convulsions.

Renal: Azotemia, hematuria, proteinuria, cystitis Reproductive: Defective oogenesis or spermatogenesis, loss of libido, impotence, gynecomastia, menstrual dysfunction Respiratory: Pulmonary fibrosis, respiratory failure, chronic interstitial obstructive pulmonary disease, pleuritic pain and thickening, alveolitis Skin: Toxic epidermal necrolysis, Stevens-Johnson syndrome, exfoliative dermatitis, skin necrosis, and erythema multiforme, erythematous rashes, pruritus, alopecia, skin ulceration, accelerated nodulosis, urticaria, pigmentary changes, ecchymosis, telangiectasia, photosensitivity, acne, furunculosis

Effects of Other Drugs on Methotrexate Drugs that Increase Methotrexate Exposure Coadministration of methotrexate with the following products may increase methotrexate plasma concentrations, which may increase the risk of methotrexate severe adverse reactions. In some cases, the coadministration of methotrexate with these products may also subsequently reduce active metabolite formation, which may decrease the clinical effectiveness of methotrexate. Increased organ specific adverse reactions may also occur when methotrexate is coadministered with hepatotoxic or nephrotoxic products.

If coadministration cannot be avoided, monitor closely for methotrexate adverse reactions when coadministered with: Nitrous Oxide Coadministration of methotrexate with nitrous oxide anesthesia potentiates the effect of methotrexate on folate-dependent metabolic pathways, which may increase the risk of severe methotrexate adverse reactions. Avoid nitrous oxide anesthesia in patients receiving methotrexate. Consider alternative therapies in patients who have received prior nitrous oxide anesthesia.

Folic Acid Coadministration of methotrexate with folic acid or its derivatives decreases the clinical effectiveness of methotrexate in patients with neoplastic diseases. Methotrexate competes with reduced folates for active transport across cell membranes. Instruct patients to take folic or folinic acid only as directed by their healthcare provider.

Pregnancy Risk Summary Methotrexate is contraindicated in pregnant women with non-neoplastic diseases. Based on published reports and its mechanism of action, methotrexate can cause embryo-fetal toxicity and fetal death when administered to a pregnant woman. There are no animal data that meet current standards for nonclinical developmental toxicity studies.

Advise pregnant women with neoplastic diseases of the potential risk to a fetus. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is respectively. Data Human Data Published data from case reports, literature reviews, and observational studies report that methotrexate exposure during pregnancy is associated with an increased risk of embryo-fetal toxicity and fetal death.

Methotrexate exposure during the first trimester of pregnancy is associated with an increased incidence of spontaneous abortions and multiple adverse developmental outcomes, including skull anomalies, facial dysmorphism, central nervous system abnormalities, limb abnormalities, and sometimes cardiac anomalies and intellectual impairment. Adverse outcomes associated with exposure during second and third trimesters of pregnancy include intrauterine growth restriction and functional abnormalities. Because methotrexate is widely distributed and persists in the body for a prolonged period, there is a potential risk to the fetus from preconception methotrexate exposure.

A prospective multicenter study evaluated pregnancy outcomes in women taking methotrexate less than or equal to 30 mg/week after conception. The rate of spontaneous abortion and miscarriage in pregnant women exposed to methotrexate was 42% (95% confidence interval 29, 59), which was higher than in unexposed patients with autoimmune disease and unexposed patients with nonautoimmune disease Of the live births, the rate of major birth defects in pregnant women exposed to methotrexate after conception was higher than in unexposed patients with autoimmune disease (adjusted odds ratio (OR) 1.8 ) and unexposed patients with non-autoimmune disease (adjusted OR 3.1 ) (2.9%). Major birth defects associated with pregnancies exposed to methotrexate after conception were not always consistent with methotrexate-associated adverse developmental outcomes.

Pediatric Use The safety and effectiveness of methotrexate in pediatric patients have been established for the treatment of ALL as part of the combination chemotherapy maintenance regimen and the treatment of pJIA. No new safety signals have been observed in pediatric patients in clinical studies. The safety and effectiveness of methotrexate have not been established in pediatric patients for the other indications.

• Methotrexate tablets are contraindicated in:
• Pregnant women receiving methotrexate tablets for treatment of non-neoplastic diseases.
• Patients with a history of severe hypersensitivity reactions, including anaphylaxis, to methotrexate.
• In pregnancy for non-neoplastic diseases
• History of severe hypersensitivity to methotrexate

Overdosage, including fatal overdosage, has occurred with methotrexate. Manifestations Manifestations of methotrexate overdosage include adverse reactions reported at pharmacologic doses, particularly hematologic and gastrointestinal reactions (e.g., leukopenia, thrombocytopenia, anemia, pancytopenia, myelosuppression, mucositis, stomatitis, oral ulceration, nausea, vomiting, gastrointestinal ulceration, or gastrointestinal bleeding). In some cases, no symptoms were reported; however, sepsis or septic shock, renal failure, and aplastic anemia were also reported.

Management Leucovorin and levoleucovorin are indicated for diminishing the methotrexate adverse reactions of methotrexate overdosage. Administer leucovorin or levoleucovorin as soon as possible after methotrexate overdosage. Monitor serum creatinine and methotrexate levels to guide leucovorin or levoleucovorin therapy.

Refer to the leucovorin or levoleucovorin prescribing information for additional dosage information. Glucarpidase is indicated for the treatment of toxic plasma methotrexate concentrations (>1 micromole per liter) in patients with delayed methotrexate clearance due to impaired renal function. Refer to the glucarpidase prescribing information for additional dosage information.

Administer concomitant hydration and urinary alkalinization. Neither hemodialysis nor peritoneal dialysis has been shown to improve methotrexate elimination; however, methotrexate has been effectively cleared with acute, intermittent hemodialysis using a high-flux dialyzer.