If you are taking methotrexate to treat rheumatoid arthritis, it may take to weeks for your symptoms to begin to improve, and 12 weeks or longer for you to feel the full benefit of methotrexate. Antineoplastic Agents may diminish the anticoagulant effect of Vitamin Antagonists. 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. Treatment in all stages methotrexate nakties laivybos usually consists of several courses of the drug interposed with to 10 day rest periods. Arthritis affects the musculoskeletal system, specifically the joints. Tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. What are the possible side effects of methotrexate? Get emergency medical help if you have any of these signs of an allergic reaction: difficulty swelling of your face, lips, tongue, or throat.