ontinue to improve for another 12 weeks or more.
The optimal duration of therapy is unknown. Limited data available from long-term studies in adults indicate that the initial clinical improvement is maintained for at least two years with continued therapy. When methotrexate is discontinued, the arthritis usually worsens within 3 to 6 weeks.
The patient should be fully informed of the risks involved and should be under constant supervision of the physician. (See Information for Patients under PRECAUTIONS.) Assessment of hematologic, hepatic, renal, and pulmonary function should be made by history, physical examination, and laboratory tests before beginning, periodically during, and before reinstituting methotrexate therapy (see PRECAUTIONS). Appropriate steps should be taken to avoid conception during methotrexate therapy (see PRECAUTIONS and CONTRAINDICATIONS).
All schedules should be continually tailored to the individual patient. An initial test dose may be given prior to the regular dosing schedule to detect any extreme sensitivity to adverse effects (see ADVERSE REACTIONS). Maximal myelosuppression usually occurs in 7 to 10 days.
Psoriasis: Recommended Starting Dose Schedules
Weekly single oral, IM or IV dosage schedule: 10 to 25 mg per week until adequate response is achieved.†
Divided oral dosage schedule: 2.5 mg at 12 hour intervals for three doses.†
†Methotrexate Sodium Tablets for oral administration are available.
Dosages in each schedule may be gradually adjusted to achieve optimal clinical response; 30 mg/week should not ordinarily be exceeded. Once optimal clinical response has been achieved, each dosage schedule should be reduced to the lowest possible amount of drug and to the longest possible rest period. The use of methotrexate may permit the return to conventional topical therapy, which should be encouraged.
Handling and Disposal: Procedures for proper handling and disposal of anticancer drugs should be considered. Several guidelines on this subject have been published.1-7 There is no general agreement that all of the procedures recommended in the guidelines are necessary or appropriate.
Reconstitution of Lyophilized Powders: Reconstitute immediately prior to use.
Methotrexate for injection should be reconstituted with an appropriate sterile, preservative free medium such as 5% dextrose solution, USP or sodium chloride injection, USP. The 1 gram vial should be reconstituted with 19.4 mL to a concentration of 50 mg/mL. When high doses of methotrexate are administered by IV infusion, the total dose is diluted in 5% dextrose solution, USP.
For intrathecal injection, reconstitute to a concentration of 1 mg/mL with an appropriate sterile, preservative free medium such as sodium chloride injection, USP.
Dilution Instructions for Liquid Methotrexate Injection: Isotonic liquid, preservative free, for single use only.
If desired, the solution may be further diluted immediately prior to use with an appropriate sterile, preservative free medium such as 5% dextrose solution,USP or sodium chloride injection, USP.
Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
HOW SUPPLIED
Methotrexate Injection, USP (preservative free) is supplied in a single-dose vial containing 25 mg/mL of methotrexate as the basein the following packagestrengths:
