MTX
Generic Name
Methotrexate 25 mg Tablet
Manufacturer
Various Generic Manufacturers
Country
Global
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Price Details
Current market pricing information
| Variant | Unit Price | Strip Price |
|---|---|---|
| mtx 25 mg tablet | ৳ 5.40 | N/A |
Description
Overview of the medicine
Methotrexate is an antimetabolite and antifolate drug used in the treatment of various cancers (e.g., leukemia, lymphoma, osteosarcoma), autoimmune diseases (e.g., rheumatoid arthritis, psoriasis, psoriatic arthritis), and for medical abortions. It works by interfering with the metabolism of folic acid, thereby inhibiting DNA synthesis and cell proliferation, particularly in rapidly dividing cells.
Uses & Indications
Dosage
Adults
Dosage varies significantly based on indication. For rheumatoid arthritis and psoriasis, typical oral doses are 7.5 mg to 25 mg once weekly, adjusted based on patient response and toxicity. For oncologic indications, doses are often much higher and administered on different schedules, sometimes with leucovorin rescue.
Elderly
Use with caution. Dosage reduction may be necessary due to age-related decrease in renal function and potential for increased susceptibility to adverse effects.
Renal_impairment
Significant dose reduction or discontinuation is required in patients with renal impairment due to the drug's primary renal excretion. Consult specific guidelines based on creatinine clearance.
How to Take
For non-oncologic indications (e.g., RA, psoriasis), methotrexate tablets are typically taken orally once weekly on the same designated day each week. It is crucial to administer exactly as prescribed due to potential for severe toxicity if taken daily or more frequently than advised. For oncologic indications, administration schedules vary widely and may include daily, weekly, or intermittent regimens.
Mechanism of Action
Methotrexate works by inhibiting dihydrofolate reductase (DHFR), an enzyme critical for the synthesis of tetrahydrofolate. Tetrahydrofolate is necessary for purine and pyrimidine nucleotide synthesis, which are essential components of DNA and RNA. By inhibiting DHFR, methotrexate depletes folate cofactors, thereby disrupting DNA replication, RNA transcription, and protein synthesis, leading to antiproliferative and cytotoxic effects. This action is particularly pronounced in rapidly dividing cells, such as cancer cells and immune cells.
Pharmacokinetics
Onset
Varies by indication. For rheumatoid arthritis, clinical effects may take 3-6 weeks. For oncologic indications, onset is much faster depending on the regimen.
Excretion
Primarily renal excretion (50-90% of unchanged drug excreted in urine within 24 hours). Minor biliary excretion also occurs.
Half life
Biphasic elimination: initial half-life of 2-4 hours, terminal phase of 8-15 hours. Can be significantly prolonged in high doses or impaired renal function.
Absorption
Well absorbed orally at low doses (up to 30 mg/m²), but bioavailability decreases with increasing dose. Peak plasma concentrations (Tmax) usually reached within 1-2 hours after oral administration.
Metabolism
Methotrexate is minimally metabolized by the liver. A small amount is converted to 7-hydroxymethotrexate, which is less active. Intracellularly, it is polyglutamated to active forms.
Side Effects
Contraindications
- •Pregnancy and Breastfeeding
- •Severe renal impairment
- •Severe hepatic impairment (including alcoholic liver disease)
- •Significant bone marrow depression/blood dyscrasias
- •Active severe infection
- •Immunodeficiency syndromes
- •Hypersensitivity to methotrexate
Drug Interactions
Alcohol
Increases the risk of hepatotoxicity. Patients should avoid or limit alcohol consumption.
Folic Acid Supplements
While often co-administered to reduce side effects, high doses or inappropriate timing can reduce methotrexate efficacy.
NSAIDs and Salicylates
Concomitant use can increase methotrexate levels and enhance toxicity, particularly at higher methotrexate doses. Use with caution or avoid.
Proton Pump Inhibitors (PPIs)
May increase methotrexate plasma concentrations, especially at high doses, leading to potential toxicity.
Antibiotics (e.g., Trimethoprim/Sulfamethoxazole, Penicillins, Ciprofloxacin)
Certain antibiotics can reduce renal clearance of methotrexate or displace it from plasma proteins, increasing toxicity.
Storage
Store at controlled room temperature between 20°C to 25°C (68°F to 77°F). Protect from light and moisture. Keep out of reach of children. Do not freeze.
Overdose
Symptoms of methotrexate overdose include severe myelosuppression, mucositis, gastrointestinal toxicity (e.g., stomatitis, diarrhea, vomiting), hepatotoxicity, and renal toxicity. Management involves immediate administration of leucovorin (folinic acid) rescue, which counteracts the effects of methotrexate by providing the necessary reduced folates. Aggressive hydration and urinary alkalinization may be used to promote excretion, especially in high-dose therapy. Dialysis is generally not effective unless active metabolites are present.
Pregnancy & Lactation
Methotrexate is contraindicated during pregnancy due to its teratogenic effects and potential for fetal death or congenital anomalies (Pregnancy Category X). Women of childbearing potential should use effective contraception during treatment and for a specified period after discontinuation (at least 6 months for women, 3 months for men). It is also contraindicated during breastfeeding as it is excreted into breast milk and can cause serious adverse effects in the infant.
Frequently Asked Questions
Common questions about this medicine
Pack Sizes
Shelf Life
24 to 36 months from the date of manufacture when stored under recommended conditions.
Availability
Pharmacies, Hospitals
Approval Status
FDA Approved
Patent Status
Off-patent
WHO Essential Medicine
YesAlternative Medicines in Bangladesh
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Global Brand Names
International brand names for this medicine
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