METHOTREXATE

Code
900.2681
Name
METHOTREXATE
Category
None
Department
Send-Out
Start Date
Expiration Date
Synonyms
Amethopterin; Mexate
CPT Codes
80299
Site
SBMF
Reference Test
23070
ATLAS Test Code

Specimen Information

Type

Red, Plain

Volume

1.0 ml

Transport Info

Refrigerated
If specimen will not be sent to SBMF on day collected
– Clot 30 minutes
– Promptly centrifuge 15 minutes
– Immediately transfer serum to separate plastic tube
PROTECT FROM LIGHT (WRAP IN FOIL OR USE AMBER PLASTIC TUBE)
Refrigerated

Fasting Required?
False
Patient Instructions

Reference Range

See Report

Methodology

Fluorescence Polarization

Clinical Significance

Monitor therapeutic drug level. Evaluate toxicity.

Methotrexate is an antineoplastic drug used solely or in combination with other antineoplastic drugs for the treatment of leukemia and other diseases. Relatively low doses of methotrexate (approximately 7.5-25 mg/week) have been used in the treatment of nonmalignant diseases such as severe psoriasis, asthma, rheumatoid arthritis, sacroidosis, and transplantation therapy. Intermediate to high doses of methotrexate (approximately 35 mg/m2-12 g/m2) with leucovorin (citrovorum-factor) rescue have been used with favorable results in the treatment of osteogenic sarcoma, leukemia, non-Hodgkin’s lymphoma, lung and breast cancer. The efficacy of methotrexate in the treatment of other tumors such as prostatic cancer is being investigated.No precise relationship between methotrexate serum levels and antineoplastic efficacy has been established, although levels below approximately 0.02 µmol/L were seen as necessary for resumption of DNA synthesis. The correlation between serum methotrexate drug concentration and duration of tumor cell exposure in predicting methotrexate toxicity has been demonstrated. Following a 4-6 hour intravenous methotrexate infusion with dosages ranging from 50 mg/m2-15 g/m2, a patient with a 24-Hour serum concentration of greater than 0.5-1.0 µmol/L, and a 72-hour level greater than 0.2 µmol/L is at an increased risk of toxicity if conventional low-dose leucovorin rescue would be indicated. Toxicity is typically present in the form of myelosuppression, stomatitis, nausea, vomiting, convulsions, and liver and renal abnormalities. Anemia, leukopenia, thrombocytopenia, osteoporosis, skin and mucosal involvement with a fatal outcome have also been reported. Neurotoxicity and leukoencephalopathy are also reported as toxic effects involving methotrexate.

Back

Patients & Visitors

Make a First Appointment Maternity Pre-Registration Make a Donation Recognize a Sarah Bush Lincoln Employee