Methotrax10 mg

Established / FDA-approved uses

• Oncology (high-dose or intensive regimens): acute lymphoblastic leukemia (including meningeal leukemia, given intrathecally), non-Hodgkin lymphoma, osteosarcoma (high-dose with leucovorin rescue), breast cancer (combination chemotherapy), advanced head and neck squamous cell carcinoma, lung cancer, and gestational trophoblastic neoplasia (choriocarcinoma, invasive mole).
• Rheumatology/Dermatology (low-dose weekly regimen): severe, active rheumatoid arthritis in adults; polyarticular-course juvenile idiopathic arthritis; severe, recalcitrant, disabling psoriasis not adequately responsive to other therapies.

Guideline-supported / commonly used (including off-label) uses

• Psoriatic arthritis and other inflammatory arthritides, as a disease-modifying agent, often in combination with other therapies.
• Maintenance of remission in Crohn's disease, as an adjunct/alternative when other agents are unsuitable.
• Medical management of early, unruptured ectopic pregnancy (single or multi-dose protocol), supported by obstetric practice guidelines, in appropriately selected patients.
• Adjunct treatment for selected autoimmune/inflammatory conditions (e.g. dermatomyositis, certain vasculitides, sarcoidosis) under specialist supervision.

Important: the dose, frequency and monitoring required differ enormously between the low-dose weekly autoimmune/dermatologic regimen and the much higher intermittent oncology regimens. See Dosage and Administration.

Each tablet/vial contains Methotrexate (as methotrexate sodium) as the active ingredient. Methotrexate is available as oral tablets (commonly 2.5 mg) and as sterile solution for injection (for intramuscular, intravenous, subcutaneous or intrathecal use) in various strengths, with standard pharmaceutical excipients.

Methotrax is a folate analogue (antimetabolite) that has been used for decades in two very different clinical contexts: as a component of high-dose, intensive cancer chemotherapy regimens, and as a low-dose, once-weekly disease-modifying agent for autoimmune and inflammatory conditions such as rheumatoid arthritis and severe psoriasis.

Because the two uses require dramatically different doses and dosing schedules, Methotrax is carried in pharmacies as either tablets (mainly for the low-dose weekly regimen) or injectable solutions (used in both settings). It carries several boxed warnings related to serious, potentially fatal toxicity, and it requires regular laboratory monitoring throughout treatment.

Antimetabolite / Folic acid antagonist (antineoplastic agent); Disease-modifying antirheumatic drug (DMARD) at low dose.

Methotrexate is a competitive inhibitor of dihydrofolate reductase (DHFR), the enzyme that converts dihydrofolate to the active tetrahydrofolate. By blocking this step, Methotrexate depletes intracellular folate cofactors needed for the synthesis of thymidylate and purine nucleotides, thereby inhibiting DNA, RNA and protein synthesis. This action is most pronounced in rapidly dividing cells (malignant cells, bone marrow, GI mucosa), which explains both its anticancer effect at high doses and its dose-limiting toxicities.

At the low weekly doses used for rheumatoid arthritis and psoriasis, the precise mechanism of anti-inflammatory action is not identical to the antiproliferative/cytotoxic mechanism at high dose; it is thought to involve increased extracellular adenosine release and other immunomodulatory effects, in addition to mild antifolate activity.

Pharmacokinetics: oral absorption is dose-dependent and may be incomplete/saturable at higher doses; bioavailability is variable between individuals. Methotrexate is partly protein-bound, distributes into third-space fluid (ascites, pleural effusions, prolonging elimination), and is eliminated primarily unchanged by the kidneys via glomerular filtration and active tubular secretion. Renal impairment substantially reduces clearance and increases toxicity risk.

Oral tablets are swallowed whole, on the prescribed day of the week, with a full glass of water. Injectable Methotrax is administered only by a trained healthcare professional via the intramuscular, subcutaneous, intravenous, or intrathecal route, according to the specific treatment protocol.

• NSAIDs and salicylates (e.g. ibuprofen, naproxen, aspirin): can reduce renal clearance of Methotrax and raise its blood levels, increasing the risk of serious, sometimes fatal, bone marrow suppression and GI toxicity. This is clinically important even at the low weekly doses used for rheumatoid arthritis; use only with close physician guidance and monitoring.
• Trimethoprim-sulfamethoxazole (co-trimoxazole) and other antifolate antibiotics: additive antifolate effect, increasing risk of severe bone marrow suppression/pancytopenia; generally avoided in patients on Methotrax.
• Proton pump inhibitors (e.g. omeprazole) and penicillins: can reduce renal elimination of Methotrax, raising blood levels, particularly relevant for high-dose regimens.
• Other hepatotoxic drugs and alcohol: increase the risk of liver injury; alcohol should be avoided during treatment (see Precautions and Contraindications).
• Live vaccines: should generally be avoided during Methotrax therapy because of immunosuppression; discuss vaccination timing with the physician.
• Folic acid/folinic acid: low-dose folic acid supplementation is standard practice with the autoimmune-disease regimen to reduce toxicity (does not reduce efficacy at these doses), but folate-containing products should not be self-adjusted; in cancer chemotherapy, folinic acid ("leucovorin rescue") is used specifically by the oncology team to reduce high-dose toxicity, and dietary folic acid supplementation is generally avoided unless directed.
• Other highly protein-bound drugs (e.g. certain sulfonamides, phenytoin): may displace Methotrax and transiently raise free drug levels.

Always tell the prescriber and pharmacist about all other medicines, supplements and herbal products being used before starting Methotrax.

Side effects depend heavily on dose. At low weekly doses (autoimmune/dermatologic use) the following are common: nausea, mouth sores/stomatitis, loss of appetite, fatigue, headache, and mild elevation of liver enzymes; these are part of why folic acid is co-prescribed.

Serious adverse effects, which are dose-related but can occur at any dose, include:

• Bone marrow suppression (low white cells, low platelets, anemia) increasing risk of infection and bleeding.
• Liver toxicity, including, with long-term low-dose use, risk of fibrosis or cirrhosis.
• Kidney toxicity, particularly with high doses.
• Serious or opportunistic infections due to immunosuppression.
• Severe gastrointestinal toxicity (mucositis, ulceration, bleeding), especially with concurrent NSAID use.
• Potentially fatal skin reactions (e.g. Stevens-Johnson syndrome, toxic epidermal necrolysis).
• Lung toxicity (interstitial pneumonitis/pulmonary fibrosis) — cough, shortness of breath or fever should be reported immediately.
• Rarely, tumor lysis syndrome in high-dose oncology use.

Patients should seek prompt medical attention for fever, unusual bruising/bleeding, mouth ulcers, yellowing of the skin/eyes, persistent cough or breathlessness, or severe skin rash.

Methotrax can cause serious birth defects, miscarriage, and fetal death, and is contraindicated in pregnancy for non-cancer indications. A pregnancy test is generally recommended before starting treatment in individuals who could become pregnant. Effective contraception should be used by patients during treatment with Methotrax and for at least 6 months after the last dose (females), and by male patients and their partners during treatment and for at least 3 months after the last dose, due to potential effects on sperm and possible genotoxicity. Anyone who becomes pregnant, or whose partner becomes pregnant, while taking Methotrax should contact their physician immediately.

In life-threatening cancer where Methotrax may sometimes still be used in pregnancy, this is only ever a specialist oncologist decision weighing maternal benefit against fetal risk.

Methotrax passes into breast milk and accumulates in infant tissues; breastfeeding is contraindicated during treatment. A physician should be consulted regarding when breastfeeding may safely resume after stopping treatment.

Boxed warnings (most serious risks)

• Dosing errors: confusing the once-weekly autoimmune/dermatologic dosing schedule with a daily schedule has caused fatal toxicity; confirm the correct weekly schedule at every prescription/refill (see Dosage and Administration).
• Hepatotoxicity: risk of liver enzyme elevation and, with long-term use, fibrosis/cirrhosis; regular liver function testing is required, and alcohol should be avoided.
• Bone marrow suppression: can be severe and unpredictable; regular complete blood counts are required.
• Serious, sometimes fatal, infections: Methotrax is immunosuppressive; report fever or signs of infection promptly.
• Gastrointestinal toxicity: mucosal ulceration and bleeding can occur, especially with concomitant NSAID use.
• Severe, potentially fatal skin reactions.
• Nephrotoxicity, especially with high-dose regimens; adequate hydration is important.
• Pulmonary toxicity (pneumonitis, fibrosis) can occur at any dose and at any time during treatment.

Monitoring

Regular blood counts, liver function tests, and renal function tests are required before starting and periodically throughout treatment with Methotrax; chest imaging may be needed if pulmonary symptoms occur.

Other precautions

Use with caution in patients with dehydration, pre-existing infections, peptic ulcer disease, or ulcerative colitis. Avoid live vaccines during treatment. Ensure adequate hydration, particularly with higher doses. Report any unusual bruising, bleeding, mouth sores, breathlessness, cough, jaundice, or rash to the physician immediately.

Overdose of Methotrax, or accidental daily instead of weekly dosing, is a medical emergency and can be fatal due to severe bone marrow suppression, mucosal/gastrointestinal ulceration, liver and kidney toxicity, and life-threatening infection. Seek immediate medical attention or contact emergency services / a poison control center if an overdose is suspected, even if the person feels well, because toxicity may be delayed.

Management is undertaken in a hospital setting and typically involves prompt administration of leucovorin (folinic acid) as an antidote, supportive care, IV fluids with urine alkalinization, monitoring of blood counts and organ function, and in severe cases with high Methotrax levels and renal impairment, specific enzymatic treatment or hemodialysis under specialist supervision. Do not attempt to manage a suspected overdose at home.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children. Injectable solutions may have specific storage requirements (some require refrigeration) — follow the instructions on the product label/pack insert.

Pregnancy and breastfeeding: see Pregnancy and Lactation — contraindicated for non-cancer use in pregnancy and during breastfeeding; effective contraception required as described.

Renal impairment: requires dose reduction and close monitoring; contraindicated in severe renal impairment because Methotrax is primarily renally cleared and toxicity risk rises sharply.

Hepatic impairment: contraindicated in significant hepatic impairment or chronic liver disease; liver function should be checked before and during therapy in all patients.

Elderly: increased susceptibility to toxicity due to age-related decline in renal/hepatic function and reduced folate stores; generally started at the lower end of the dose range with close monitoring.

Immunocompromised patients or those with active infection: Methotrax should not be used in patients with a serious active infection or significant immunodeficiency.

For autoimmune/dermatologic conditions, Methotrax is typically continued long-term (months to years) at the lowest effective once-weekly dose, with regular monitoring, as long as it remains effective and well tolerated, under ongoing physician supervision. For cancer, duration and number of cycles are determined by the specific chemotherapy protocol and response to treatment. Treatment should never be stopped or its schedule changed without consulting the prescribing physician.

Certain injectable powder-for-solution presentations of Methotrax require reconstitution with an appropriate diluent by a healthcare professional strictly according to the product's package insert before administration; oral tablets and pre-filled/ready-to-use injectable solutions do not require reconstitution.

Antimetabolites; Folate antagonists; Antineoplastic agents; Disease-modifying antirheumatic drugs (DMARDs).

Methotrexate competitively and reversibly inhibits dihydrofolate reductase, blocking conversion of folate to its active tetrahydrofolate form, thereby impairing synthesis of thymidylate and purines needed for DNA/RNA replication in rapidly dividing cells; at low weekly doses it also has folate-independent anti-inflammatory/immunomodulatory effects relevant to its use in autoimmune disease.

X (legacy FDA pregnancy category) for non-oncologic indications — contraindicated in pregnancy.

Methotrax is FDA-approved for polyarticular-course juvenile idiopathic arthritis, with dosing individualized by body surface area/weight and determined by a pediatric rheumatologist, generally given once weekly with the same critical weekly-dosing safety precautions that apply to adults. It is also used, under oncologist supervision, in pediatric cancer protocols (e.g. acute lymphoblastic leukemia).

Safety and efficacy for indications outside these established pediatric uses have not been established, and Methotrax should only be used in children under the direct supervision of a specialist experienced in its use, with the same rigorous monitoring (blood counts, liver and kidney function) as in adults. Caregivers must be clearly instructed on the once-weekly schedule to prevent dosing errors.