Intravenously, intramuscularly, intraarterially, intrathecally. The contents of the vial are dissolved with a sterile isotonic sodium chloride solution immediately before use. 1 gram (1000 milligrams) methotrexate diluted 0.9% isotonic saline, 20 ml to a concentration of 50 mg / ml.The resulting solution methotrexate if necessary may be further diluted in an isotonic sodium chloride solution or 5% dextrose solution.
Doses above 100 mg / m2 administered only intravenously, the pre-diluted lyophilizate methotrexate, further diluted with 5% dextrose. When prescribing high doses of the drug (above 100 mg / m2) necessarily the subsequent introduction of calcium folinata.
For the intrathecal administration of methotrexate solution was diluted lyophilisate 50 mg / ml, further diluted to a concentration of 1 mg / ml in 0.9% isotonic sodium chloride solution.
Malignant neoplasms
Vero-methotrexate is a part of many chemotherapy regimens, therefore, when selecting the route of administration, regimen and dosage in each individual case, one should be guided by the data of specialized literature.The following dosing regimens are used in adults and children: Trophoblastic tumors: 15-30 mg intramuscularly, daily for 5 days with an interval of one or more weeks (depending on signs of toxicity). Treatment rates are usually repeated 3 to 5 times to a total dose of 300-400 mg.
Leukemia and lymphoma: 200-500 mg / m2 by intravenous infusion once every 2-4 weeks.
Neuroleukemia: 12 mg / m2 for 15-30 seconds intrathecally 1 or 2 times a week.
When treating children, the dose is selected depending on the age of the child: children under the age of 1 year are prescribed 6 mg, children aged 1 year 8 mg, children 2 years 10 mg, children 3 years and over -12 mg.
Before administration, it is necessary to remove cerebrospinal fluid in a volume approximately equal to the volume of the drug to be injected.
With caution, enter intrathecally. Exceeding the recommended dose with intrathecal administration significantly increases the risk of significant manifestations of toxicity. Caution: do not enter calcium folinate intrathecally!
Solid tumors: in combination with other antitumor drugs 30-40 mg / m2 intravenously sprayed once a week.
When high-dose therapy is administered from 2 to 15 g / m2 a 4-6 hour intravenous infusion at intervals of 1-5 weeks followed by optional introduction of calcium folinate which typically begin 24 hours after the start of infusion and methotrexate administered every 6 hours in a dose of 3-40 mg / m2 (usually 15 mg / m2) and above, depending on the concentration of methotrexate in the blood serum for 48-72 hours (see instructions for the use of calcium folinate).
Precautions for use.
Methotrexate is a cytotoxic drug, so care must be taken when handling it.
When high doses of methotrexate are administered, careful monitoring of the patient's condition is necessary to detect early signs of toxic reactions early.
With care, enter intertecally. Exceeding the recommended dose with intrathecal administration significantly increases the risk of significant manifestations of toxicity.
High-dose therapy (at a dose of 2 g / m2 and above) should be performed only by an experienced chemotherapist under the control of methotrexate concentration in plasma under steady-state conditions.Normal decrease in the content of methotrexate in blood plasma is considered 2 times as compared to the initial value in 22 hours after the administration. Increase in plasma concentrations of creatinine (by 50% or more from the original) and / or bilirubin requires intensive detoxification therapy.
During therapy with methotrexate in elevated and high doses, it is necessary to monitor the pH of the urine: on the day of administration and in the next 2-3 days, the urine reaction should be alkaline. This is achieved by intravenous drip injection of a mixture consisting of 40 ml of 4.2% sodium bicarbonate solution and 400-800 ml of 0.9% sodium chloride solution on the eve, on the day of treatment and subsequent 2-3 days. Treatment with methotrexate in high and high doses should be combined with enhanced hydration (up to 2 liters of fluid per day).
For the treatment of psoriasis methotrexate appoint only patients with severe disease that can not be treated by other types of therapy.
To timely detect symptoms of intoxication during treatment with methotrexate, it is necessary to monitor the parameters of peripheral blood (1 time per week), the functional state of the liver and kidneys.
With the development of diarrhea and ulcerative stomatitis, methotrexate therapy must be interrupted due to the high risk of developing hemorrhagic enteritis and perforation of the intestinal wall, which can lead to the death of the patient.
In patients with impaired liver function, the period of excretion of methotrexate is increased, therefore, in such patients therapy should be carried out with extreme caution, with the use of reduced doses.
Impaired renal function is dose dependent. Risk of impairment is elevated in patients with reduced renal function or with dehydration, as well as in patients taking other nephrotoxic drugs.
Men and women of childbearing age should be treated with methotrexate and at least 3 months after the use of reliable methods of contraception.