Mtx
Generic Name
Methotrexate 50 mg Injection
Manufacturer
Various generic manufacturers globally
Country
Multiple countries (Global production)
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Price Details
Current market pricing information
| Variant | Unit Price | Strip Price |
|---|---|---|
| mtx 50 mg injection | ৳ 130.00 | N/A |
Description
Overview of the medicine
Methotrexate is an antimetabolite and antifolate drug used in the treatment of various cancers, autoimmune diseases like severe psoriasis, rheumatoid arthritis, and Crohn's disease. It works by interfering with the growth of certain cells, particularly rapidly multiplying cells like cancer cells, and by suppressing the immune system.
Uses & Indications
Dosage
Adults
Varies widely based on indication, severity, and patient factors. For rheumatoid arthritis/psoriasis, typically 7.5-25 mg once weekly (oral or parenteral). For oncological uses, doses can range from low (e.g., 20-50 mg/m² weekly) to very high (e.g., >1000 mg/m² with leucovorin rescue).
Elderly
Use with caution; dosage adjustments may be necessary due to decreased renal function and reduced hepatic reserve. Close monitoring is essential.
Renal_impairment
Significant dosage reduction or discontinuation is required based on creatinine clearance, as methotrexate is primarily renally excreted. High risk of toxicity with impaired renal function.
How to Take
For injection, it can be administered intravenously (IV), intramuscularly (IM), subcutaneously (SC), or intrathecally (IT), depending on the specific indication and formulation. High doses typically require IV infusion. Administer under the supervision of a physician experienced in chemotherapy/immunosuppression.
Mechanism of Action
Methotrexate works by reversibly inhibiting dihydrofolate reductase (DHFR), an enzyme that participates in the tetrahydrofolate synthesis. This prevents the reduction of dihydrofolate to tetrahydrofolate, which is a crucial cofactor in the synthesis of purine nucleotides and thymidylate. This inhibition leads to the depletion of nucleotide precursors, thereby inhibiting DNA, RNA, and protein synthesis, particularly in rapidly dividing cells (e.g., cancer cells, activated immune cells).
Pharmacokinetics
Onset
Variable depending on indication; for RA, effects may be seen within 3-6 weeks; for cancer, effects are more acute.
Excretion
Primarily excreted unchanged by the kidneys via glomerular filtration and active tubular secretion. Biliary excretion is minimal.
Half life
Approximately 3-10 hours in low doses (e.g., for RA/psoriasis) and 8-15 hours in high doses (e.g., for cancer).
Absorption
Rapidly and completely absorbed after parenteral administration (IM, IV, SC). Bioavailability is nearly 100% with injection.
Metabolism
Partially metabolized in the liver to 7-hydroxymethotrexate (minor active metabolite) and polyglutamated forms (intracellularly).
Side Effects
Contraindications
- •Severe renal impairment
- •Severe hepatic impairment
- •Pre-existing blood dyscrasias (e.g., bone marrow hypoplasia, leukopenia, thrombocytopenia, significant anemia)
- •Active infectious diseases
- •Immunodeficiency syndromes
- •Alcoholism
- •Pregnancy and breastfeeding (except for specific indications like ectopic pregnancy)
- •Known hypersensitivity to methotrexate
Drug Interactions
Probenecid
Decreases renal excretion of methotrexate, potentially increasing toxicity.
Live vaccines
Risk of severe adverse reactions due to immunosuppression. Avoid concurrent administration.
Folic acid/Folates
Can reduce the efficacy of methotrexate; usually given as leucovorin rescue after high-dose methotrexate, or as a supplement (e.g., folic acid) on non-methotrexate days to reduce side effects in low-dose therapy.
Penicillins/Sulfonamides
May reduce renal clearance of methotrexate, leading to increased plasma concentrations and toxicity.
Proton Pump Inhibitors (PPIs)
Omeprazole and other PPIs may reduce the renal elimination of methotrexate, leading to elevated and prolonged serum methotrexate levels, especially with high doses.
NSAIDs (e.g., Ibuprofen, Naproxen)
May increase methotrexate levels and toxicity, especially with high-dose methotrexate. Use with caution or avoid.
Storage
Store at room temperature (20-25°C) or as specified by manufacturer, protected from light. Do not freeze. Keep out of reach of children.
Overdose
Symptoms of overdose include severe bone marrow suppression, mucositis, gastrointestinal toxicity, and liver damage. Treatment involves immediate administration of leucovorin (folinic acid) in escalating doses, and hydration with alkalinization of urine to promote methotrexate excretion. Glucarpidase may be used in cases of very high plasma methotrexate concentrations and renal impairment.
Pregnancy & Lactation
Pregnancy Category X (contraindicated due to high risk of fetal death and severe birth defects), except in specific life-threatening oncological indications where benefits may outweigh risks, or for medical termination of ectopic pregnancy. Breastfeeding is contraindicated due to excretion in breast milk and potential for serious adverse effects in the infant.
Frequently Asked Questions
Common questions about this medicine
Pack Sizes
Shelf Life
Typically 24-36 months from manufacture, when stored as directed.
Availability
Hospitals, specialist clinics, retail pharmacies (with prescription)
Approval Status
Approved by major regulatory bodies (e.g., FDA, EMA, DGDA)
Patent Status
Off-patent (Generic available)
WHO Essential Medicine
YesAlternative Medicines in Bangladesh
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Global Brand Names
International brand names for this medicine
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