Methotrexate is used as maintenance therapy for childhood acute lymphoblastic leukaemia. Other uses include choriocarcinoma, and a number of solid tumours.. Methotrexate is used alone or in combination with other anticancer agents in the treatment of breast cancer, epidermoid cancers of the head and neck, advanced mycosis fungoides, and lung cancer, particularly squamous cell and small cell types. Methotrexate is also used in combination with other chemotherapeutic agents in the treatment of advanced stage non-Hodgkin\\\'s lymphomas. Methotrexate can be used for Crohn\\\'s disease and severe psoriasis. Also used in moderate to severe active rheumatoid arthritis.
Dosage & Administration
Choriocarcinoma and similar trophoblastic diseases: Methotrexate is administered orally in doses of 15 to 30 mg daily for a five-day course. In acute lymphoblastic leukemia in children methotrexate in doses of 3.3 mg/m2 in combination with 60 mg/m2 of prednisone, given daily, produced remissions in 50% of patients treated usually within a period of 4 to 6 weeks. In Burkitt\\\'s tumor, Stages I-II, recommended dosage is 10 to 25 mg/day orally for 4 to 8 days. In Stage III, methotrexate is commonly given concomitantly with other antitumor agents. Treatment in all stages usually consists of several courses of the drug interposed with 7 to 10 day rest periods. Lymphosarcomas in Stage llI may respond to combined drug therapy with methotrexate given in doses of 0.625 to 2.5 mg/kg daily. In mycosis fungoides Dosage in early stages is usually 5 to 50 mg once weekly. Methotrexate has also been administered twice weekly in doses ranging from 15 to 37.5 mg in patients who have responded poorly to weekly therapy. Adult Rheumatoid Arthritis: Recommended Starting Dosage Schedules Single oral doses of 7.5 mg once weekly. Divided oral dosages of 2.5 mg at 12 hour intervals for 3 doses given as a course once weekly. Psoriasis: Recommended Starting Dose Schedules Weekly single oral, IM or IV dose schedule: 10 to 25 mg per week until adequate response is achieved. Divided oral dose schedule: 2.5 mg at 12-hour intervals for three doses. Dosages in each schedule may be gradually adjusted to achieve optimal clinical response; 30 mg/week should not ordinarily be exceeded.
it is necessary to follow patients on methotrexate closely. Most adverse reactions are reversible if detected early. When such reactions do occur, the drug should be reduced in dosage or discontinued and appropriate corrective measures should be taken. If necessary, this could include the use of leucovorin calcium. If methotrexate therapy is reinstituted, it should be carried out with caution, with adequate consideration of further
need for the drug and with increased alertness as to possible recurrence of toxicity. The clinical pharmacology of methotrexate has not been well studied in older individuals. Due to diminished hepatic and renal function as well as decreased folate stores in this population, relatively low doses should be considered, and these patients should be closely monitored for early signs of toxicity. Baseline assessment should include a complete blood count with differential and platelet counts, hepatic enzymes, renal function tests, and a chest X-ray. During therapy of rheumatoid arthritis and psoriasis, monitoring of these parameters is recommended: hematology at least monthly, renal function and liver function every 1 to 2 months. More frequent monitoring is usually indicated during antineoplastic therapy. During initial or changing doses, or during periods of increased risk of elevated methotrexate blood levels (eg, dehydration), more frequent monitoring may also be indicated.
Transient liver function test abnormalities are observed frequently after methotrexate administration and are usually not cause for modification of methotrexate therapy. Persistent liver function test abnormalities, and/or depression of serum albumin may be indicators of serious liver toxicity and require evaluation.In pregnancy and lactation.