💉 DESCRIPTION
Methotrexate Injection 50 mg/mL is a cytotoxic antimetabolite used for treating various malignancies and autoimmune diseases. It is administered by intravenous (IV), intramuscular (IM), subcutaneous (SC), or intra-arterial (IA) routes depending on the indication.
- Generic Name: Methotrexate
- Strength: 50 mg/mL
- Form: Solution for Injection
- Class: Antimetabolite, Immunosuppressant, DMARD
- Common Brand Names: Trexall®, Methoblastin®, Rheumatrex®, Emthexate®
✅ ADVANTAGES
- Versatile administration (IV, IM, SC, intrathecal, intra-arterial)
- Preferred in high-dose regimens for cancers
- Avoids gastrointestinal side effects of oral methotrexate
- Can be used when oral administration is not feasible
- More predictable absorption and bioavailability
🌿 NATURE / MECHANISM OF ACTION
- Methotrexate inhibits dihydrofolate reductase (DHFR)
- This prevents the formation of tetrahydrofolate, needed for DNA, RNA, and protein synthesis
- Results in suppression of rapidly dividing cells, including cancer and immune cells
- At low doses, has anti-inflammatory and immunomodulatory effects
⚠️ PRECAUTIONS
- Cytotoxic: Handle with gloves; avoid skin or eye contact
- Monitor for:
- Bone marrow suppression (CBC regularly)
- Hepatotoxicity (LFTs), nephrotoxicity (RFTs)
- Pulmonary toxicity (pneumonitis)
- Intrathecal use requires preservative-free formulation
- Use leucovorin rescue after high-dose methotrexate to reduce toxicity
- Pregnancy Category X: Highly teratogenic
- Avoid in patients with active infections, renal impairment, or liver disease
💉 ROUTES OF ADMINISTRATION
- IV: For high-dose therapy in cancers (e.g., leukemia, lymphoma, osteosarcoma)
- IM / SC: For autoimmune conditions like rheumatoid arthritis, psoriasis
- Intra-thecal: For CNS leukemia (must be preservative-free)
- Intra-arterial: In specific regional chemotherapy protocols
🧊 STORAGE
- Store at 2°C to 8°C (refrigerated)
- Do not freeze
- Protect from light
- Single-use vial – discard unused portion
- Follow cytotoxic handling protocols for disposal
👨⚕️ PATIENT ADVICE
- Administered by healthcare professionals only
- Do not self-administer
- Report signs of toxicity:
- Fever, sore throat, mouth ulcers, bleeding, yellowing of eyes/skin, difficulty breathing
- Avoid alcohol, NSAIDs, and live vaccines
- Women and men must use effective contraception during and after therapy
- Regular blood and liver tests are mandatory
- Hydration and urine alkalinization are essential during high-dose therapy
📦 PACKAGING
- Supplied in amber glass vials, usually:
- 2 mL vial = 100 mg (50 mg/mL)
- 10 mL vial = 500 mg
- Labeled with:
- Product name: Methotrexate Injection 50 mg/mL
- Manufacturer details, batch number, expiry date
- Cytotoxic warning and dosage information
- Requires prescription and cytotoxic drug handling protocols