This medication is used to treat rheumatoid arthritis, a condition in which the body's defense system (immune system) fails to recognize the body as itself and attacks the healthy tissues around the joints. Leflunomide helps to reduce the joint damage/pain/swelling and helps you to move better. It works by weakening your immune system and decreasing swelling (inflammation).

Take this medication by mouth with or without food, usually once daily or as directed by your doctor. Take this medication exactly as prescribed. You may be instructed to take a higher dose for the first 3 days of treatment. Dosage is based on your medical condition and response to therapy. Take this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time each day. After treatment is stopped, a different drug (cholestyramine) may be given as directed to help remove leflunomide from your body. This procedure is used if you need a rapid removal of the drug from your system (e.g., a female/male planning to have children, a person suffering from severe side effects). Without the procedure, the drug may stay in your body for up to 2 years. Consult your doctor or pharmacist for more details. Inform your doctor if your symptoms persist or worsen.

Before taking leflunomide, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. Before using this medication, tell your doctor or pharmacist your medical history, especially of: immune system disorder (e.g., HIV infection), current/recent infection (e.g., tuberculosis), cancer, bone marrow/blood disorder, kidney disease, liver disease (e.g., hepatitis B or C), alcohol abuse, heart disease (e.g., congestive heart failure), lung disease. This drug may make you dizzy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Avoid alcoholic beverages since they can make you dizzy and also cause liver disease. Do not have immunizations/vaccinations without the consent of your doctor, and avoid contact with people who have recently received oral polio vaccine or flu vaccine inhaled through the nose. Since this medication can increase your risk of developing serious infections, wash your hands well to prevent the spread of infections. Avoid contact with people who have illnesses that may spread to others (e.g., flu, chickenpox). This medication must not be used during pregnancy. It may harm an unborn baby. Before starting this medication, women of childbearing age must have a negative pregnancy test before starting this medication. Men and women must use two effective forms of birth control (e.g., condoms and birth control pills) while taking this medication. Consult your doctor for more details and to discuss reliable forms of birth control. (See also Warning section.) It is not known whether this medication affects the sperm. To minimize any possible risk, the manufacturer recommends that men wishing to father a child should consider stopping the medication and using another drug (cholestyramine) as directed to help this drug leave the body before attempting to father a child. (See How to Use section.) Consult your doctor for more details. This drug may pass into breast milk and could have undesirable effects on a nursing infant. Therefore, breast-feeding is not recommended while using this drug. Consult your doctor before breast-feeding.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

See also How to Use Section. Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first. Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: warfarin, rifamycins (e.g., rifampin), drugs affecting the liver (e.g., methotrexate), cholestyramine, other drugs that weaken the immune system (e.g., tacrolimus, cyclosporine). This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

Diarrhea, nausea, and dizziness may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor immediately if any of these unlikely but serious side effects occur: cough, numbness/tingling of hands/feet, hair loss, chest pain, fast/pounding heartbeat, increased thirst/urination, muscle cramp/pain, mental/mood changes, vision changes. Tell your doctor immediately if any of these rare but very serious side effects occur: easy bruising/bleeding, unusual growths/lumps, swollen glands (lymph nodes), unexplained weight loss, unusual tiredness. This medication can lower the body's ability to fight an infection. Tell your doctor immediately if you develop any signs of an infection such as fever, chills, or persistent sore throat. A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any of the following symptoms of a serious allergic reaction: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. Leflunomide can commonly cause a mild rash that is usually not serious. However, you may not be able to tell it apart from a rare rash that could be a sign of a severe allergic reaction. Therefore, seek immediate medical attention if you develop any rash. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Store at room temperature at 77 degrees F (25 degrees C) away from light and moisture. Brief storage between 59-86 degrees F (15-30 degrees C) is permitted. Do not store in the bathroom. Keep all medicines away from children and pets. Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.