Pfizer Methotrexate Injection 25mg/mL

Adult dosage

1. Leukemia: Administer 5～10 mg of methotrexate orally per day for 3～6 days per week. 2. Trophoblastic disease: Administer 10～30 mg orally per day. Use a 5-day treatment cycle, and repeat after a drug-free period of 7～12 days. 3. Rheumatoid arthritis: Administer 7.5～20 mg orally once weekly, or administer 2.5 mg orally 3 times at 12-hour intervals. The total weekly dose should not exceed 20 mg. 4. Psoriasis: Administer 7.5～20 mg orally once weekly, or orally in 3 divided doses at 12-hour intervals. Adult dosing for injectable formulation: It is recommended to administer a test dose of 5～10 mg orally once, 1 week before treatment, to test for idiosyncratic adverse reactions. For patients with severe, refractory psoriasis, 10～25 mg may be administered orally once weekly or by intravenous/intramuscular injection. Adjust the dose according to the patient's response.

Children's dosage

1. Leukemia: Administer 1.25～2.5 mg per day to infants and 2.5～5 mg per day to children orally for 3～6 days per week. Pediatric dosing for injectable formulation: - Meningeal leukemia: Administer 12～15 mg/㎡ (0.4～0.5 mg per kg of body weight) by intrathecal injection at 1-week intervals until the cerebrospinal fluid returns to normal. - Trophoblastic disease: Administer 10～30 mg/㎡ per day by intramuscular injection for 5 days, followed by a drug-free period of 7～12 days. The cycle may be repeated 3～5 times.

This drug should only be taken once a week for the treatment of rheumatoid arthritis or psoriasis, as dosing errors can lead to serious side effects. Combination therapy with certain anticancer drugs is risky, so caution is advised under a doctor's supervision. High-dose use with proton pump inhibitors may increase toxicity, so caution is necessary. Patients who are hypersensitive to any component of this drug, have poor kidney or liver function, are pregnant or may become pregnant, and nursing mothers should not be administered this medication. Patients with diarrhea, stomatitis, gastric ulcers, blood disorders, infections, etc., should be administered with caution, and children and elderly patients should also be closely monitored. During administration, various severe adverse reactions such as shock, gastrointestinal bleeding, pneumonia, hepatitis, and renal failure can occur, so symptoms should be reported to medical staff immediately. Regular monitoring of bone marrow function, liver and kidney function, and blood tests is essential to detect any abnormalities early and respond accordingly. This drug affects reproductive function and poses a serious risk to the fetus during pregnancy; hence, women who are pregnant or planning to become pregnant should avoid use, and men should also use contraception for a certain period during and after treatment. This drug interacts with many other medications, so caution is required when taken together, especially when drugs that may delay renal excretion and increase toxicity are involved. In case of overdose, an antidote should be administered immediately, and appropriate medical treatment is necessary; it cannot be removed by hemodialysis, so careful management is required. This medication should be stored out of reach of children and should not be transferred to another container.

• Shock
• symptoms of anaphylaxis
• hemorrhagic colitis
• necrotizing colitis
• abdominal pain
• diarrhea
• nausea
• vomiting
• stomatitis
• loss of appetite

This medication should be stored in a sealed container to prevent air entry and kept in a cool place below 25 degrees Celsius, protected from direct sunlight.

Appearance

A clear vial containing a yellow clear liquid injection.

Package unit

50mg/2mL x 5 vials, 500mg/20mL x 1 vial