Leflunomide is a generic drug prescribed for rheumatoid arthritis in adults. As with other drugs, leflunomide can cause side effects, such as eye problems and skin rash.

Leflunomide is available as the brand-name drug Arava.

Leflunomide comes as an oral tablet.

Read on to learn about potential common, mild, and serious side effects of leflunomide. For details about its uses and more, refer to the leflunomide oral tablet overview.

Leflunomide has boxed warnings. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). For details, see the “Leflunomide: Side effect specifics” section.

Leflunomide can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took leflunomide in clinical trials:

Mild side effects can occur with leflunomide use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to the prescribing information.

Mild side effects that have been reported with leflunomide include:

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the FDA approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking leflunomide and want to tell the FDA about it, visit MedWatch.

Leflunomide may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to the drug’s prescribing information.

If you develop serious side effects while taking leflunomide, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

Note: A boxed warning is the most serious warning from the FDA. For details about leflunomide’s warnings, see the “Leflunomide: Side effect specifics” section.

ALLERGIC REACTION

For some people, leflunomide oral tablet can cause an allergic reaction.

In general, symptoms of allergic reaction can be mild or serious.

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to leflunomide oral tablet, your doctor may recommend taking a different medication instead.

Leflunomide may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

How safe is leflunomide?

In general, the benefits of leflunomide treatment outweigh its potential and known risks for most adults with rheumatoid arthritis (RA). That said, some side effects of leflunomide are serious and can become life threatening. For some people with RA, the drug is not a safe treatment option, and there may be better choices.

For example, leflunomide is not safe to take during pregnancy because there’s a risk of fetal harm. The drug is also toxic to the liver with the potential to cause serious liver damage. In fact, leflunomide has boxed warnings about the risks of fetal harm and liver damage. To learn more about these risks, see “Leflunomide: Side effect specifics” later in the article.

Your doctor can provide more information about whether leflunomide is safe for you given your overall health and other factors.

How do the side effects of leflunomide 10 mg vs. 20 mg compare?

In most cases, the side effects are expected to be similar whether your daily dosage is 10 milligrams (mg) or 20 mg. However, the risk of certain side effects increases with higher doses. These include liver damage and bone marrow problems.

The recommended dosage of leflunomide is 20 mg per day. But if you’re experiencing side effects from the drug, your doctor may decrease your dosage to 10 mg per day.

If you have concerns about the risk of side effects with your leflunomide dosage, talk with your doctor.

Are there side effects of stopping leflunomide?

It’s not likely. Stopping leflunomide didn’t cause withdrawal symptoms in clinical trials of the drug. (Withdrawal symptoms are uncomfortable side effects that can occur when you stop taking a drug your body is used to.)

However, stopping leflunomide may cause your RA symptoms to come back or worsen.

Before stopping leflunomide, it’s important to talk with your doctor. They can determine the best way to stop taking the drug. They can also discuss alternative medications for your condition. Learn more about RA treatment options.

Learn more about some of the side effects that leflunomide may cause. To find out how often side effects occurred in clinical trials, see the drug’s prescribing information.

Harm to a fetus if taken during pregnancy

Leflunomide has a boxed warning about the risk of fetal harm if taken during pregnancy. A boxed warning is the most serious warning from the FDA. It alerts doctors and patients about drug effects that may be dangerous.

Leflunomide can cause harm to a fetus if the drug is taken during pregnancy. Due to this risk, your doctor will not prescribe leflunomide if you’re pregnant or planning to become pregnant.

As well, they’ll likely have you take a pregnancy test before starting leflunomide to make sure you’re not pregnant. They’ll also recommend that you use an effective form of birth control during and for up to 2 years after stopping leflunomide treatment.

What you can do

If you become pregnant while taking leflunomide, talk with your doctor right away. They’ll likely have you stop taking leflunomide. They’ll also prescribe medications or other treatments to help clear leflunomide from your body more quickly.

Severe liver damage

Leflunomide also has a boxed warning about the risk of severe liver damage.

Taking leflunomide can increase your risk of severe liver damage, including liver failure and even death. Severe liver injury is a rare but serious side effect of leflunomide. Although it didn’t appear to occur in clinical trials, there have been reports of liver damage and fatal liver failure since the drug became available.

Symptoms may include:

Your risk of liver damage may be higher if you already have liver disease or elevated liver enzymes before starting leflunomide.

Due to this risk, your doctor will likely not prescribe leflunomide if you have severe liver problems. They’ll also order blood tests to monitor your liver enzymes at least monthly for the first 6 months of treatment and every 6 to 8 weeks afterward.

What you can do

If you develop any symptoms of liver problems, contact your doctor right away. They’ll likely have you stop taking the drug and give you treatment to clear the drug from your body quickly. They may also order blood tests to make sure your liver enzymes are decreasing into the normal range.

If you have questions about how toxic leflunomide is to the liver, talk with your doctor or pharmacist. They can also explain drug-induced liver injury and treatment options.

Below is important information you should consider before taking leflunomide oral tablet.

Leflunomide has boxed warnings. A boxed warning is the most serious warning from the FDA. For details, see the “Leflunomide: Side effect specifics” section.

Other precautions

Before taking leflunomide, discuss your health history with your doctor. Leflunomide may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

Disclaimer: Medical News Today 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 another 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.