Methotrexate 2.5 mg Dosage/Direction for Use

Single doses, not exceeding 30 mg/m², on not more than 5 successive days are recommended. A rest period of 2 weeks is recommended between treatments, in order to allow normal functioning of the bone marrow.
Methotrexate may be used alone or in combination chemotherapy with radiotherapy or surgery. Dosage regimens may therefore vary considerably.
Folinic acid (Leucovorin) is used to counteract the folate antagonist action of Methotrexate and thus speed recovery from Methotrexate induced mucositis or myelosuppression. Dosage regimens for Leucovorin rescue vary, depending on the dose of Methotrexate administered. In general up to 120 mg in divided doses over 12 to 24 hours by intramuscular or intravenous injection or infusion, followed by 12 to 15 mg intramuscularly or 15 mg by mouth every 6 hours for the next 48 hours are recommended. The dosage of Methotrexate should be reduced during combination chemotherapy.
Single weekly doses of 10 to 25 mg may be given by mouth in the treatment of psoriasis. Dosage should be adjusted according to the patient's response and the haematological toxicity.