Highlights for leflunomide

  1. Leflunomide oral tablet is available as a generic drug and a brand-name drug. Brand name: Arava.
  2. Leflunomide only comes as a tablet you take by mouth.
  3. Leflunomide is used to treat active rheumatoid arthritis. It can help reduce the pain in your joints and help you perform daily tasks better.

Important warnings

FDA warning:

  • This drug has black box warnings. A black box warning is the most serious warning from the Food and Drug Administration (FDA). A black box warning alerts doctors and patients about drug effects that may be dangerous.
  • Pregnancy risk warning. You shouldn’t take this medication if you’re pregnant. In addition, you shouldn’t take it if you’re of childbearing age and not using effective birth control methods to prevent pregnancy. Avoid becoming pregnant while taking this medication. If you become pregnant, talk to your doctor.
  • Liver damage warning. Liver damage can occur in anyone taking this drug. People with existing liver damage shouldn’t take this drug. Your doctor may do blood tests to measure liver function at least monthly for 6 months while you take this drug.

Other warnings

  • Infection warning: This drug isn’t recommended if you have a weak immune system or serious infections. If you get a serious infection, such as pneumonia or tuberculosis, talk to your doctor to find out if you should stop taking this medication.
  • Nerve damage warning: This medication can damage the nerves in some people and cause numbness, tingling, or burning pain in the hands and feet. This can go away once the drug is stopped. However, some people continue to have symptoms.
  • Blood cell level warning: Your doctor may monitor your blood cell levels regularly. Talk to your doctor if you experience fevers, unusual tiredness, frequent infections, or bruise or bleed easily.

What is leflunomide?

This drug is a prescription medication. It comes as a tablet you take by mouth.

Leflunomide is available as the brand-name drug Arava. It’s also available in a generic version. Generic drugs usually cost less. In some cases, they may not be available in every strength or form as the brand-name version.

Why it's used

This drug is used to treat active rheumatoid arthritis.

How it works

Rheumatoid arthritis occurs when your immune system becomes overactive and attacks some parts of your body, such as your joints. This drug works to block part of the immune system and proteins in the body that cause inflammation.

This drug is a nonbiologic disease-modifying anti-rheumatic drug (DMARD).

Leflunomide side effects

Leflunomide oral tablet does not cause drowsiness, but it can cause other side effects.

More common side effects

The more common side effects of leflunomide include:

  • diarrhea
  • hair loss
  • rash
  • worsening liver function

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • serious infections, including pneumonia, tuberculosis, and complications from infections
  • serious skin disorder. Symptoms may include:
    • flu-like symptoms
    • painful red or purple rash
    • blisters
  • low blood cell counts. Your doctor may monitor this through blood tests.
  • worsening lung function. Symptoms may include:
    • cough
    • trouble breathing, with or without fever

If you experience a side effect with leflunomide, or are at risk for a serious side effect, you may receive other oral medications to help remove leflunomide from your body more rapidly. This can help prevent future side effects.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.

Leflunomide may interact with other medications

Leflunomide oral tablet can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Examples of drugs that can cause interactions with leflunomide are listed below.

Disease-modifying antirheumatic drug

Combining methotrexate with leflunomide may increase your risk of liver damage.


Combining rifampin with leflunomide may cause higher levels of leflunomide in your body. This may increase side effects of leflunomide.

Blood thinner

Combining warfarin with leflunomide may decrease the effect of warfarin on your blood. You may need to have blood tests performed more often or have your dose of warfarin changed while taking leflunomide.

Live vaccines

Talk to your doctor or pharmacist before receiving live vaccinations. Leflunomide decreases immune function. This may increase your risk of getting the disease the vaccine is designed to prevent. Live vaccines include:

  • influenza nasal spray
  • measles, mumps, and rubella vaccine
  • chickenpox (varicella) vaccine

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

Leflunomide warnings

This drug comes with several warnings.

Allergy warning

This drug can cause a severe allergic reaction. Symptoms can include:

  • trouble breathing
  • swelling of your throat or tongue
  • hives

If you develop these symptoms, call 911 or go to the nearest emergency room.

Don’t take this medication again if you’ve ever had an allergic reaction to this drug or teriflunomide. Taking it again could be fatal.

Warnings for people with certain health conditions

For people with liver disease: If you have liver problems, using this drug may cause even more damage to your liver. This drug isn’t recommended if you have liver disease.

For people with kidney disease: Talk to your doctor about using this drug if you have kidney problems. Higher levels of the drug may stay in your body if your kidneys don’t work well. It’s unknown if this would cause more side effects.

For people with serious infection: This drug isn’t recommended if you have a weak immune system or serious infections. If you get a serious infection, such as pneumonia or tuberculosis, talk to your doctor to find out if you should stop taking this medication.

Warnings for other groups

For pregnant women: This drug is a pregnancy category X drug. Category X drugs should never be used during pregnancy.

For men: It isn’t known if this drug can pass into your sperm. Taking this drug during conception could harm the development of the fetus.

For women who are breastfeeding: It isn’t known if this drug passes through breast milk. It isn’t recommended for women to breastfeed while using this drug. You and your doctor may need to decide whether you’ll breastfeed or take this drug.

For children: This drug is not approved for people under the age of 18 years.

How to take leflunomide

All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

Drug forms and strengths

Generic: Leflunomide

  • Form: oral tablet
  • Strengths: 10 mg, 20 mg, and 100 mg

Brand: Arava

  • Form: oral tablet
  • Strengths: 10 mg, 20 mg, and 100 mg

Dosage for active rheumatoid arthritis

Adult Dosage (ages 18 years and older)

  • Some people receive a starting dose of one 100-mg tablet per day for 3 days. This is called a “loading dose.”
  • The recommended daily dose for continuing treatment is 20 mg. If you’re unable to tolerate this dose, your doctor may lower it to 10 mg per day.
  • Doses higher than 20 mg per day are not recommended.

Child dosage (ages 0–17 years)

Dosage for people younger than 18 years hasn’t been established.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always speak with your doctor or pharmacist about dosages that are right for you.

Take as directed

Leflunomide is used for long-term treatment. It comes with risks if you don’t take it as prescribed.

If you stop taking the drug or don’t take it at all: Rheumatoid arthritis can cause severe pain and affect other organs in your body, especially if left untreated. It’s important to continue taking your medication as directed by your doctor, even if you feel better. This will give you the best chance of managing rheumatoid arthritis and improving your quality of life.

If you take too much: You may experience more side effects, including diarrhea, stomach pain, and changes in your blood cell levels and liver function. You may need to take another medication to help get rid of excess leflunomide in your body more quickly. If you take or think you’ve taken too much leflunomide, get medical help right away.

What to do if you miss a dose: If you miss a dose, take it as soon as you can. If it’s close to time for your next dose, skip the missed dose and take the next dose at the usual time. Don’t take more than one dose at a time or extra doses. Doing so could lead to more side effects.

How to tell if the drug is working: You should have less joint pain and be able to perform your daily tasks better.

Important considerations for taking this drug

Keep these considerations in mind if your doctor prescribes leflunomide for you.


Don’t cut or crush the oral tablet. This drug is considered a hazardous material and shouldn’t be broken apart and handled.


  • Store this medication at 77°F (25°C).
  • Keep it away from light.
  • Don’t store this medication in moist or damp areas, such as bathrooms.


A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.


When traveling with your medication:

  • Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
  • Don’t worry about airport X-ray machines. They won’t damage your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.

Clinical monitoring

This drug may affect your liver function and blood levels in your body. Your doctor may order blood tests monthly for the first 6 months that you take it, and then every 6–8 weeks after that.

A pregnancy test is required before starting this drug. If you think you’re pregnant while taking this drug, tell your doctor immediately. You may need to take another pregnancy test.

Prior authorization

Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.