Drug General Information (ID: DDIOLXWYZ7)
  Drug Name Sulfasalazine Drug Info Leflunomide Drug Info
  Drug Type Small molecule Small molecule
  Therapeutic Class Antiinflammatory Agents Antiinflammatory Agents
  Structure

 Mechanism of Sulfasalazine-Leflunomide Interaction (Severity Level: Major)
     Additive immunosuppressive effects Click to Show/Hide Mechanism Graph
Could Not Find 2D Structure
      Drug Name Sulfasalazine Leflunomide
      Mechanism Immunosuppressive effects Immunosuppressive effects
      Key Mechanism Factor 1
Factor Name Immunosuppressive effects
Factor Description Immunosuppression is when your immune system is not functioning as it should. The immune system is made up of cells, tissues and organs that help the body fight off infections. If the immune system is suppressed, an infection that your body was able to control may become serious or even fatal.
      Mechanism Description
  • Additive immunosuppressive effects by the combination of Sulfasalazine and Leflunomide 

Recommended Action
      Management Concomitant use of leflunomide with other immuno- or myelosuppressive antirheumatic agents should generally be avoided. When switching from leflunomide to one of these agents, consideration should be given to administering a washout procedure with cholestyramine or activated charcoal to accelerate elimination of leflunomide's active metabolite from plasma, which otherwise may take up to two years. This will decrease the overlap of systemic exposure to both compounds and reduce the likelihood of additive hematologic toxicities. However, the washout procedure may also induce disease worsening if the patient had been responding to leflunomide treatment. Patients who do not receive the washout procedure prior to switching should be monitored closely for hematologic toxicity. All patients treated with leflunomide should be advised to contact their physician if they develop signs and symptoms of infection such as fever, chills, diarrhea, sore throat, muscle aches, shortness of breath, blood in phlegm, weight loss, red or inflamed skin, body sores, and pain or burning during urination. If evidence of serious infection or bone marrow suppression occurs, treatment with leflunomide should be stopped and washout procedure administered.

References
1 Cerner Multum, Inc. "UK Summary of Product Characteristics.".
2 Product Information. Arava (leflunomide). Hoechst Marion-Roussel Inc, Kansas City, MO.