Leflunomide (Leflun) is a drug used to treat certain types of cancer. It is not known if it works in other diseases. Leflunomide was developed by Bayer Pharmaceuticals and marketed under the trade names Remicade, Leucovorin, and Metacam. It was approved by the FDA in 1999 for treatment of lung cancer. Its most common use is to reduce pain associated with chemotherapy or radiation therapy. Leflunomide is a prescription medicine and must be prescribed by your doctor. Some studies have shown that it may help prevent the spread of some cancers such as liver, colon, stomach, kidney, brain tumors and leukemia. Other studies show no benefit at all.
The main ingredient in leflunomide is methotrexate. It is found in many over-the-counter medicines including Tylenol and Advil.
You will need to take a special dose of leflunomide every day. This medication is usually taken once daily. If you are taking leflunomide, you may experience side effects such as nausea, vomiting, diarrhea, fatigue and headache. These symptoms occur when the body does not absorb enough of the active ingredients in leflunomide. This is known as a low-dose of leflunomide. If these side effects become worse or last longer, contact your health care provider immediately.
Do not drink alcohol while taking leflunomide, as it can cause negative interactions between the two types of medicine. Be sure to tell your health care provider if you are taking any type of prescription or over-the-counter drug or herbal supplement.
Some types of drugs should not be taken with leflunomide including:
Other anti-cancer drugs.
Cholesterol-lowering drugs such as clofibrate, fenofibrate, and gemfibrozil.
Barbiturates such as phenobarbital.
Sedatives or tranquilizers such as diazepam and chlordiazepoxide.
Non-steroidal anti-inflammatory drugs such as naproxen, ibuprofen, and piroxicam.
Oral anticoagulants to thin the blood such as warfarin.
Some other drugs can cause negative interactions if taken with leflunomide. Be sure to tell your health care provider if you are taking any of the drugs listed below.
Antibiotics such as ciprofloxacin, clarithromycin, erythromycin, and telithromycin.
Azole antifungals such as fluconazole, itraconazole, ketoconazole, and voriconazole.
HIV drugs such as etravirine, nevirapine, rilpivirine, and ritonavir.
Non-nucleoside reverse transcriptase inhibitors such as delavirdine, efavirenz, etravirine, and nevirapine.
Your doctor will monitor your condition and vital signs while you are taking leflunomide. If you begin to lose too much weight, your doctor may decrease the amount of leflunomide you are taking or temporarily stop the medication.
It is important to take this medication every day as directed. Do not stop taking it unless your health care provider tells you to do so.
It can take a few months before you can tell if this medication is working for you.
Does leflunomide cause birth defects?
There is a risk of birth defects if you become pregnant while using leflunomide and for three months after stopping it. If you think you could be pregnant, contact your doctor immediately.
What is the most important information I should know about leflunomide?
Before taking leflunomide, tell your health care provider if you have any medical conditions. Tell your health care provider if you are pregnant or think you might be pregnant. It is not known if this medication can harm an unborn baby. It is not known if leflunomide passes into your milk. Do not use this medication without telling your doctor if you are breastfeeding a baby.
The US Food and Drug Administration has issued a warning on the use of leflunomide (Arava) in children due to the risk of severe liver damage. Leflunomide is not approved for use in children.
Leflunomide can cause a serious type of liver damage called acute hepatotoxicity. Common symptoms include nausea, vomiting, loss of appetite, itching, yellowing of your skin or whites of your eyes, dark urine, and pale stools.
If you have these symptoms contact your doctor immediately. Leflunomide can also cause liver failure resulting in death.
If you have other health problems besides rheumatoid arthritis, your condition may get worse while using leflunomide. Tell your health care provider if you have any new or worsening symptoms.
You may experience headache, diarrhea, nausea, weakness, or irritability. If you experience any of these symptoms, contact your doctor.
You may need to have regular blood tests to check your liver function while taking leflunomide.
Be sure to carry your medication record with you in case of an emergency, including hospitalizations.
What do I do if I miss a dose?
If you miss a dose, take it as soon as you can. If you do not remember until it is time for your next dose, just take the next dose as usual. Do not take two doses at once.
What precautions should I take when taking leflunomide (Arava)?
Before starting leflunomide, tell your health care provider if you have any medical conditions, especially if you have liver or kidney problems. You may not be able to take this medication.
Do not take additional NSAIDs while taking leflunomide. This includes ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn), or prescription or over-the-counter medicines that contain these medicines.
Avoid drinking alcohol while you are taking this medication unless your doctor tells you it is okay.
You may get drowsy or dizzy. Do not drive or operate machinery until you know how the medication affects you.
Does leflunomide (Arava) affect pregnancy?
If you are pregnant, contact your doctor. You will need to discuss the benefits and risks of taking leflunomide while you are pregnant. Leflunomide is found in the mother’s milk, so it is not recommended for use by breastfeeding mothers.
What if I take an overdose of leflunomide (Arava)?
An overdose of leflunomide is unlikely to cause life-threatening symptoms in terms of over-dosing on the drug itself. If you do feel unwell after taking an overdose of this medication, you should seek immediate medical attention.
What should I do in case of accident of overdose?
In the event of an accident or overdose, seek immediate medical attention. Take the medication container with you to help with the medical diagnosis.
What other information should I know about leflunomide (Arava)?
Your health care provider will monitor your condition on a regular basis while you are taking this medication.
Leflunomide is not a cure for rheumatoid arthritis. It will reduce pain, swelling, and joint damage in many people.
However, it may not relieve inflammation in everyone. You should know that it has been known to take up to 4-6 weeks to see the full effect of this medication.
Sources & references used in this article:
Clinical pharmacokinetics of leflunomide by B Rozman – Clinical pharmacokinetics, 2002 – Springer
Formulation and in-vitro evaluation of leflunomide oral tablet with enhanced dissolution by AA Ammar, SA Eladawy, GH Elosaily… – Journal of American …, 2015 – researchgate.net
Treatment of patients with juvenile rheumatoid arthritis with combination of leflunomide and methotrexate by JS Gao, H Wu, J Tian – Zhonghua er ke za zhi= Chinese journal of …, 2003 – europepmc.org