The potential benefits of disease-modifying antirheumatic drugs (DMARDs) should be weighed against possible side effects. The condition being treated will influence the choice and dosage of DMARDs. A physician should be consulted regularly during any treatment program involving DMARDs.

Patients who regularly use DMARDs are often carefully monitored for side effects in several ways, such as blood tests, urine tests, eye exams and chest x-ray. Depending on the disease, the DMARDs prescribed and the overall condition of the patient, certain side effects may occur. They include:  

• Stomach pain, diarrhea or constipation
• Nausea or vomiting
• Headache
• Joint pain or swelling
• Skin rash
• Increased sensitivity to sunlight
• Mouth or throat sores
• High blood pressure
• Increased vulnerability to infection, including in the eyes
• Cold or flu-like symptoms, such as fever
• Hair loss
• Low blood count, low white blood cell count

Rheumatoid arthritis (RA) has been linked to increased risk of developing lymphoma. Some studies have suggested that this could be due to use of certain DMARDs, but recent research indicates that the inflammation of RA may account for the cancer risk and that the medications do not appear to be a factor, with the possible exception of azathioprine, which is seldom used to treat RA.