Methotrexate and emerging therapies.

It is likely that all new therapeutic interventions will be used with methotrexate in combination therapy. These combinations may yield real therapeutic advances. The potential for end organ toxicity, opportunistic infection, and malignancy will need to be carefully monitored with long-term, meticulously conducted observational studies. Expense, ease of use, and perceived benefit-to-risk ratio will determine which new agents become most commonly prescribed with methotrexate.