If you have rheumatoid arthritis (RA), your doctor might suggest Arava (leflunomide) as a treatment option for you. Along with other questions you may have about the drug, you could be wondering about its side effects.

Arava is a prescription medication that’s used to treat RA in adults. It comes as a tablet you take by mouth, and it’s meant to be used as a long-term treatment.

For more information about Arava, see this in-depth article on the drug.

Like other drugs, Arava can cause mild or serious side effects. Keep reading to learn more.

Some people may experience mild or serious side effects during Arava treatment.

Examples of Arava’s commonly reported side effects include:

* To learn more about this side effect, see the “Side effects explained” section below.

Read on to learn about other possible mild and serious side effects of Arava.

Arava may cause mild side effects for some people.

Examples of mild side effects that have been reported with Arava include:

* To learn more about this side effect, see the “Side effects explained” section below.

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And don’t stop taking Arava unless your doctor recommends it.

Arava may cause mild side effects other than the ones listed above. See the Arava prescribing information for details.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Arava, visit MedWatch.

In rare cases, serious side effects can happen with Arava.

Serious side effects that have been reported with Arava include:

* Arava has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effects explained” section below.
† Arava has a boxed warning for this side effect. To learn more, see “Pregnancy and breastfeeding while taking Arava” under the “Warnings for Arava” section below.
‡ To learn more about this side effect, see the “Side effects explained” section below.

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

Learn more about some of the side effects Arava may cause.

Hair loss

Hair loss is a common side effect of Arava.

Keep in mind that rheumatoid arthritis (RA), which Arava is used to treat, can cause hair loss. So it’s possible you may have hair loss due to your condition.

What might help

While taking Arava, treating your hair gently may help reduce hair loss. This includes not brushing it too much or using styling tools that are harsh on your hair, such as a curling iron. For other hair loss prevention tips, see this article.

If you have bothersome hair loss while taking Arava, talk with your doctor. They can help determine if your hair loss may be caused by Arava or by RA. They can also suggest more ways to ease this side effect.

Liver problems

Arava has a boxed warning for liver problems. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

Liver problems, such as liver failure, weren’t reported by people taking Arava in studies. But they have been reported since the drug became publicly available for use. In rare cases, this side effect has been fatal.

Symptoms of liver problems can include:

What might help

If you have symptoms of liver problems while taking Arava, tell your doctor right away.

Before you start taking Arava, your doctor will give you liver function tests. And they’ll give you these tests throughout treatment. If you develop liver problems while taking Arava, your doctor will likely have you stop taking the drug.

Your doctor may monitor you more closely for liver problems if you take Arava with other RA drugs that cause this side effect. An example is Trexall (methotrexate).

Digestive system problems

Problems with the digestive system are a common side effect of Arava. Examples include:

In some cases, these problems can lead to dehydration (low level of fluid in your body). This happens because nausea, vomiting, and diarrhea can cause your body to lose large amounts of water and electrolytes.

What might help

If you have digestive system problems while taking Arava, it’s important to stay hydrated. Be sure to drink plenty of water, or sports drinks such as Gatorade.

If you have severe digestive system problems that last longer than a couple of days, tell your doctor right away. They can suggest ways to ease your symptoms. And your doctor or pharmacist can suggest medications for these problems that are safe to take with Arava.

Allergic reaction

Like most drugs, Arava can cause an allergic reaction in some people.

Symptoms can be mild or serious and may include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. To manage your symptoms, they may suggest an over-the-counter antihistamine you take by mouth, such as Benadryl (diphenhydramine). Or they may recommend a product you apply to your skin, such as hydrocortisone cream.

If your doctor confirms you had a mild allergic reaction to Arava, they’ll decide if you should continue taking it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you had a serious allergic reaction to Arava, they may have you switch to a different treatment.

Keeping track of side effects

During Arava treatment, consider keeping notes on any side effects you’re having. Then, you can share this information with your doctor. This is especially helpful to do when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of drug you were taking when you had the side effect
  • how soon after starting that dose you had the side effect
  • what your symptoms were from the side effect
  • how it affected your daily activities
  • what other medications you were also taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help your doctor learn more about how Arava affects you. And your doctor can use this information to adjust your treatment plan if needed.

Below are answers to a few frequently asked questions about Arava’s side effects.

Do Arava’s side effects vary depending on the tablet strength (10 mg, 20 mg, or 100 mg)?

Not necessarily. Studies of Arava didn’t show any differences in side effects based on the drug’s strength.

If you’re concerned about your risk of side effects with Arava based on the strength you take, talk with your doctor or pharmacist.

How long will Arava’s side effects last?

Studies of Arava haven’t reported the length of time Arava’s side effects are expected to last.

For many drugs, side effects are expected to be temporary. They usually go away soon after you start taking the drug.

But keep in mind that Arava can stay in your system for a long time after you stop taking it. For some people, it can take up to 2 years for the drug to leave their system entirely. If the drug stays in your system for a long time, you may experience long-term side effects.

If you’re having bothersome side effects after you’ve stopped taking Arava, talk with your doctor. They may give you treatments to help your body get rid of Arava faster. And they can advise on the treatment plan that’s right for you.

Do I have a higher risk of side effects from Arava because of my age?

It depends. It’s possible that your age may raise your risk of certain side effects from Arava.

For example, Arava may cause peripheral neuropathy. This condition is caused by nerve damage and leads to pain, numbness, and weakness in your hands or feet. You may have a higher risk of this side effect if you’re age 60 years or older.

If you’re concerned about your risk of side effects from Arava because of your age, talk with your doctor or pharmacist.

Below are several warnings for Arava.

Boxed warnings

Arava has boxed warnings about liver problems and fetal harm if taken during pregnancy. Boxed warnings are the most serious warnings from the Food and Drug Administration (FDA).

  • Liver problems. Arava can cause serious liver problems, including liver failure. In rare cases, this can be fatal. To learn more, see the “Side effects explained” section above.
  • Fetal harm if taken during pregnancy. You should not take Arava if you’re pregnant or planning to become pregnant. For details, see the “Pregnancy and breastfeeding while taking Arava” section below.

Other warnings

Arava may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Arava. The list below includes factors to consider.

High blood pressure. Arava may cause high blood pressure. If you already have this condition, Arava may raise your blood pressure even more. Your doctor can discuss with you if it’s safe for you to take Arava.

Active infection. Before starting Arava treatment, tell your doctor if you have an active infection. They’ll likely treat the infection before you start taking the drug.

Lung problems. Taking Arava can cause new or worsening lung problems, such as swelling or scarring in the lungs. Be sure to tell your doctor if you have lung problems before starting Arava treatment. They may recommend a drug other than Arava for you.

Weakened immune system. If you have a weakened immune system, your doctor may not prescribe Arava for you. Having a weakened immune system may increase your risk of serious infections, such as tuberculosis. Before taking Arava, be sure to tell your doctor if you have a weakened immune system. They may prescribe a different treatment for you.

Allergic reaction. If you’ve had an allergic reaction to Arava or any of its ingredients, you shouldn’t take Arava. Ask your doctor what other medications are better options for you.

Alcohol and Arava

It should be safe to drink alcohol in moderation during Arava treatment.

Keep in mind that drinking large amounts of alcohol may cause liver disease. Liver problems are a possible serious side effect of Arava.* So drinking large amounts of alcohol while you’re taking the drug may raise your risk of liver problems.

Alcohol may also worsen symptoms of rheumatoid arthritis (RA), which Arava is used to treat. If you know alcohol worsens RA symptoms for you, you’ll likely want to avoid alcohol while taking Arava.

If you drink alcohol, talk with your doctor about the amount that’s safe for you to drink while taking Arava.

* Arava has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effects explained” section above.

Pregnancy and breastfeeding while taking Arava

Below is information about taking Arava during pregnancy and breastfeeding.

Arava and pregnancy

You should not take Arava if you’re pregnant or planning to become pregnant. In fact, the drug has a boxed warning about fetal harm if taken during pregnancy. A boxed warning is a serious warning from the FDA.

Arava can cause harm to a fetus. Because of this, your doctor will make sure you have a negative pregnancy test before starting Arava treatment. If you become pregnant while taking Arava, tell your doctor right away.

If you can become pregnant, you should use an effective form of birth control while taking Arava. And you may need to continue using birth control for up to 2 years after you stop taking this drug.

Tell your doctor if you plan to become pregnant within 2 years after stopping Arava treatment. They may give you treatments to help your body get rid of the drug faster. This could lower the risk of fetal harm if you become pregnant during this time.

Pregnancy registry

If you become pregnant while taking Arava, consider taking part in a pregnancy registry.

A pregnancy registry helps gather information on how certain drugs can affect pregnancy. To learn more, call 877-311-8972, visit this registry website, or talk with your doctor.

Arava and breastfeeding

It isn’t known if Arava passes into breast milk. It may not be safe to take the drug while you’re breastfeeding.

If you’re breastfeeding or planning to breastfeed while taking Arava, talk with your doctor. They’ll likely recommend that you don’t breastfeed while taking this drug.

Arava is a long-term treatment option for rheumatoid arthritis (RA).

If you’re considering Arava as a treatment option, talk with your doctor or pharmacist about its possible side effects. Below are a few questions you may want to ask:

  • Do I have any health conditions that may raise my risk of side effects from Arava?
  • What should I do if I become pregnant while taking Arava?
  • How can I manage side effects I may have with Arava?

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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 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.