Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Alcohol: The liver helps to break down leflunomide into chemicals that are active in the body. Alcohol is also broken down by the liver. The combination of leflunomide and alcohol may result in more harm to the liver than if either one were used on its own. To reduce the risk of severe liver injury, you should avoid alcohol during treatment with leflunomide.
Birth defects: Leflunomide can cause birth defects in children whose fathers were using it at the time of conception. For this reason, a man planning a family must first stop taking the medication and consult with his doctor. Otherwise, he should use condoms during sexual intercourse.
If either partner is taking leflunomide, a reliable method of birth control should always be used throughout the course of treatment with leflunomide. Women should avoid pregnancy for 2 years after taking leflunomide (or for as long as a certain level of the medication and its byproducts remain in the body).
Blood clotting: This medication can reduce the number of platelet cells in the blood. Platelets help the blood to clot, and a shortage could make you bleed more easily. Tell your doctor of any signs that your blood is not clotting as quickly. Such symptoms may include black and tarry stools.
Blood pressure: Leflunomide frequently causes increased blood pressure. For this reason, it is important to monitor your blood pressure on a regular basis while taking this medication.
Infection: Leflunomide works on the immune system to help reduce the damage that parts of the immune system cause to the body. It can reduce the number of cells that fight infection in the body (white blood cells). As a result, leflunomide may reduce the body's ability to fight severe infections.
Tell your doctor immediately if you notice signs of an infection, such as fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness. Your doctor will do regular blood tests to monitor the number of specific types of blood cells in your blood.
Avoid immunizations without your doctor's approval.
Kidney function: The kidneys help to remove this medication from the body. When the kidneys are not working well, leflunomide can build up in the body and cause serious side effects. If you have reduced kidney function or kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
This medication should not be used by anyone who has moderately to severely reduced kidney function.
Liver function: Leflunomide can cause damage to the liver, including liver failure, and should not be used by anyone who has reduced liver function or liver disease.
If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.
Lung inflammation: Lung inflammation (interstitial lung disease), causing difficulty breathing has occurred rarely in some people taking this medication. This complication can be serious and sometimes fatal. If you experience new or worsening shortness of breath or cough (with or without fever) at any time while you are taking leflunomide contact your doctor immediately.
Red blood cells: Leflunomide may cause low levels of red blood cells. If you experience symptoms of reduced red blood cell count (anemia) such as shortness of breath, feeling unusually tired, or pale skin, contact your doctor as soon as possible.
Pregnancy: This medication is likely to cause serious harm and birth defects to the unborn baby if it is taken by a pregnant mother. It is important that leflunomide is not used during pregnancy or by women who may become pregnant. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding: This medication may pass into breast milk. If you are a breast-feeding mother and are taking leflunomide it may affect your baby. Due to the seriousness of the effects that a breast-feeding infant would experience, women taking this medication should be advised not to breast-feed.
Children: The safety and effectiveness of leflunomide has not been established for children under the age of 18 years.