Drugs for rheumatoid arthritis work by blocking parts of the immune system from wreaking havoc. Most people with rheumatoid arthritis start with the disease-modifying antirheumatic drug (DMARD) methotrexate, usually taken as a pill (but is also available as an injection). It has a proven track record as an effective medication. There are other DMARDs as well. Methotrexate doesn't work well enough for everyone, and some people have side effects.