How the interaction occurs:
Your body process leflunomide to its active form. Rifampin may speed up this process.
What might happen:
The amount of active drug in your blood may increase and it may cause more side effects than expected.
What you should do about this interaction:
Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together or if you have used rifampin in the previous two weeks. Let your doctor know right away if you develop any signs of an infection such as a fever, cough, chills, or sore throat; numbness/tingling of hands/feet; hair loss; chest pain; fast/pounding heartbeat; increased thirst/urination; muscle cramps/pain; mental/mood changes; vision changes; easy bruising/bleeding, unusual growths/lumps; swollen glands (lymph nodes); unexplained weight loss; and/or unusual tiredness.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.Reference:1.Arava (leflunomide) US prescribing information. Aventis Pharmaceuticals, Inc. November, 2012.