Xatmep Dosage

Important Administration Information

XATMEP is intended for oral use only. Use another formulation of methotrexate for alternative dosing in patients who require dosing via other routes of administration. Instruct patients and caregivers that the recommended dose should be taken weekly, as directed, and that mistaken daily use of the recommended dose has led to fatal toxicity [see Warnings and Precautions (5.15), Overdosage (10)].

It is important that XATMEP be measured with an accurate measuring device [see Warnings and Precautions (5.15), Patient Counseling Information (17)]. A household teaspoon is not an accurate measuring device. A pharmacist can provide an appropriate device and can provide instructions for measuring the correct dose.

Acute Lymphoblastic Leukemia

The recommended starting dose of XATMEP, in multi-agent combination chemotherapy maintenance regimens, is 20 mg/m2 given one time weekly. After initiating XATMEP, continuation of appropriate dosing requires periodic monitoring of absolute neutrophil count (ANC) and platelet count to assure sufficient drug exposure (that is to maintain ANC at a desirable level) and to adjust for excessive hematological toxicity.

Polyarticular Juvenile Idiopathic Arthritis

The recommended starting dose of XATMEP is 10 mg/m2 given one time weekly.

Dosages should be tailored to the individual patient and adjusted gradually to achieve an optimal response. Although there is experience with doses up to 30 mg/m2/week in pediatric patients, doses greater than 20 mg/m2/week may result in a significant increase in the incidence and severity of serious toxic reactions, especially bone marrow suppression. Doses between 20 and 30 mg/m2/week (0.65 to 1 mg/kg/week) may have better absorption and fewer gastrointestinal side effects if methotrexate is administered by an alternative route using another formulation.

Therapeutic response usually begins within 3 to 6 weeks and the patient may continue to improve for another 12 weeks or more.

Certain side effects such as mouth sores may be reduced by folate supplementation with methotrexate in pJIA.

Evaluations Prior to Starting Methotrexate

Assess hematologic, hepatic, and renal function before beginning, as well as periodically during and before reinstituting, therapy with XATMEP [see Warnings and Precautions (5.1, 5.3, 5.5, 5.7, 5.14)]. Exclude pregnancy in females of reproductive potential before starting XATMEP [see Contraindications (4), Warnings and Precautions (5.9), Use in Specific Populations (8.1, 8.3)].

Handling Information

XATMEP is a cytotoxic drug. Follow applicable special handling and disposal procedures.1