When Methotrexate is discontinued, the arthritis usually worsens within 3 to 6 weeks. Therapeutic response usually begins within 3 to 6 weeks and the patient may continue to improve for another 12 weeks or more.
Dose reduction or cessation is guided by patient response and hematologic monitoring.
As the time interval between Methotrexate administration and leucovorin initiation increases, the effectiveness of leucovorin in counteracting toxicity decreases.
Dosages ranged up to 25 mg per week and treatment was administered for up to four years.
Close attention to renal function including adequate hydration, urine alkalinization and measurement of serum Methotrexate and creatinine levels are essential for safe administration. This lesion can occur at all dosages.
When a patient presents with pulmonary symptoms, the possibility of Pneumocystis carinii pneumonia should be considered. Immunization may be ineffective when given during Methotrexate therapy.
