In the U.S.—

• Antirheumatic (disease-modifying)

Leflunomide (le-FLUN-o-mide) is used to relieve some symptoms caused by rheumatoid arthritis, such as inflammation, swelling, stiffness, and joint pain. This medicine works by stopping the body from producing too many of the immune cells that are responsible for the swelling and inflammation.

This medicine is available only with your doctor's prescription, in the following dosage form(s):

Oral
• Tablets (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For leflunomide, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to leflunomide. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Leflunomide must not be taken during pregnancy because it may cause birth defects in humans. Women of childbearing age are advised to use reliable contraception before receiving leflunomide.

Breast-feeding—It is not known whether leflunomide passes into the breast milk. However, leflunomide is not recommended during breast-feeding, because it may cause unwanted effects in nursing babies.

Children—Although there is no specific information comparing use of leflunomide in children with use in any other age group, use is not recommended in children up to 18 years of age.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way as they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of leflunomide in the elderly with use in other age groups.

Males

Studies have not been done in animals or humans to determine if leflunomide will cause birth defects in the children of men taking leflunomide at the time of conception. However, it is recommended that men taking this medicine use condoms as a form of birth control during sexual intercourse. Men taking leflunomide who intend to father a child, should stop taking the medicine and tell their doctor immediately.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your health care professional if you are taking any other prescription or nonprescription (over-the-counter [OTC] medicine.

• Disease of the immune system or
• Infections, severe—Leflunomide may decrease the body's ability to fight infection

• Liver disease, including hepatitis B or C or
• Renal disease—The chance of side effects may be increased

Take this medicine only as directed by your doctor. Do not take more or less of it, and do not take it more often than your doctor ordered.

Dosing—

The dose of leflunomide will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of leflunomide. If your dose is different, do not change it unless your doctor tells you to do so.

• For oral dosage form (tablets):
  • For rheumatoid arthritis:
    • Adults—At first, 100 mg once a day for three days, then 20 mg once a day. Your doctor may decrease the dose as needed.
    • Children—Use and dose must be determined by your doctor.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible. However, if you do not remember the missed dose until the next day, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

It is important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

Leflunomide may cause birth defects in humans if taken during pregnancy. Therefore, if you suspect that you may have become pregnant, stop taking this medicine immediately and check with your doctor.

Leflunomide may cause birth defects in the children of the men taking it during the time of conception. Therefore, men taking leflunomide should use condoms as a form of birth control during sexual intercourse. A man intending to father a child should stop taking this medicine and check with his doctors.

Do not drink alcohol while using this medicine. Alcohol can increase the chance of liver problems.

While you are being treated with leflunomide, and after you stop treatment with it, do not have any immunizations (vaccinations) without your doctor's approval.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• More common
  • Bloody or cloudy urine;  congestion in chest;  cough;  difficult, burning, or painful urination;  difficult or painful breathing;  dizziness;  fever ;  frequent urge to urinate;  headache;  loss of appetite;  nausea and/or vomiting;  sneezing;  sore throat;  yellow eyes and/or skin 
  
  

• Less common
  • Burning feeling in chest or stomach;  burning, prickling, or tingling sensation in fingers and/or toes;  chest pain;  diarrhea;  fast heartbeat;  indigestion;  joint or muscle pain or stiffness;  pounding heartbeat ;  severe stomach pain;  shortness of breath;  tenderness in stomach area;  unusual tiredness or weakness 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Back pain;  hair loss;  heartburn;  skin rash;  stomach pain;  weight loss (unexplained) 
  
  

• Less common
  • Acne;  anxiety;  constipation;  decreased appetite;  dry mouth;  gas;  irritation or soreness of mouth;  itching of the skin;  pain or burning in throat;  red or irritated eyes;  runny nose 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.