Low dose therapy: choriocarcinoma, lymphotic leukemia, breast carcinoma.
High dose therapy: malignant melanoma, osteogenic sarcoma, epidermoid carcinoma of neck and head, small cell carcinoma of lung.
Nononcology use: Psoriasis <2021/6/2>
#仿單變更2021

Methotrexate and its polyglutamate metabolites reversibly inhibit dihydrofolate reductase, the enzyme that reduces folic acid to tetrahydrofolic acid.

Psoriatic patients with severe renal or hepatic disorder, blood dyscrasia, pregnant women.

X/D in controversy

Contraindicated

Nausea, vomiting, leukopenia, thrombocytopenia, stomatitis, diarrhoea, hepatic and lung fibrosis.

2.5-5mg/day or 15-50mg/m2 every 1-2 weeks
Psoriasis: Initial 10 to 25 mg given once weekly, or 2.5 to 5 mg every 12 hours for 3 times /week; adjust dose gradually to optimal response; in general, doses >25 mg per week should not be exceeded. Consider a test dose in patients with risk factors for hematologic toxicity, hepatotoxicity, or renal impairment. <2021/6/2>

CrCl (30-59 mL/min): Reduce the therapeutic dose by 50% and avoid high-dose therapy.
CrCl (10-29 mL/min): Avoid use. If no suitable alternative therapy is available, reduce the dose by 50%.
CrCl (<10 mL/min): Avoid use.
<20240503>