If you have rheumatoid arthritis (RA) or another autoimmune condition, your doctor may recommend Xeljanz (tofacitinib). Knowing this drug’s possible side effects may help you and your doctor decide if it’s a good treatment option for you.

When you have an autoimmune condition, your immune system attacks your own body. Xeljanz is effective in reducing symptoms of some of these conditions. In addition to RA, Xeljanz is used to treat adults who have:

If Xeljanz works for you, your doctor may recommend the medication as a long-term treatment option.

Xeljanz comes as an oral solution or a tablet that you take by mouth. The tablet is available in either an immediate-release or extended-release form. The extended-release tablet, Xeljanz XR, releases medication into your body slowly over time. Both Xeljanz and Xeljanz XR have the same risks of side effects.

For more information about Xeljanz, including details about its uses, see this in-depth article on the drug.

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

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

Listed here are just a few of the more common side effects reported by people who took Xeljanz in studies. These side effects can vary depending on what condition the drug is being used to treat.

More common side effects in people taking Xeljanz for rheumatoid arthritis, psoriatic arthritis, or juvenile idiopathic arthritis include:

More common side effects in people taking Xeljanz for ulcerative colitis include:

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

You may have mild side effects while you’re taking Xeljanz. If you have any that are bothersome, be sure to talk with your doctor. They may be able to recommend ways to decrease these side effects.

These side effects can vary depending on what condition you’re using the drug to treat.

Examples of mild side effects that have been reported in people taking Xeljanz for rheumatoid arthritis, psoriatic arthritis, or juvenile idiopathic arthritis include:

Examples of mild side effects that have been reported in people taking Xeljanz for ulcerative colitis include:

* To learn more about this side effect, see “Side effects explained” 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 using Xeljanz unless your doctor recommends it.

Xeljanz may cause mild side effects other than the ones listed above. For more information, see the Xeljanz medication guide.

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

Some people have serious side effects from taking Xeljanz. Although these side effects are rare, you should be aware of any that may occur. This way you can notify your doctor about them immediately. Serious side effects that have been reported with Xeljanz include:

* To learn more about this side effect, see “Side effects explained” below.
Xeljanz 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 “Side effects explained” below.
‡ An allergic reaction is possible after using Xeljanz. In studies, there were reports of swelling of the lips and rash, which may indicate an allergic reaction.

If you develop serious side effects while taking Xeljanz, 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.

Get answers to some frequently asked questions about Xeljanz’s side effects below.

Does Xeljanz cause hair growth or hair loss?

It depends. Some studies have shown that people with alopecia may benefit from taking Xeljanz. Alopecia is an autoimmune disease that causes hair loss. At this time, Xeljanz isn’t used to treat alopecia.

As for hair loss, you shouldn’t experience this as a side effect of Xeljanz. Hair loss wasn’t reported in people who took Xeljanz in studies.

If you’re concerned about hair loss, talk with your doctor. They may be able to recommend medications to decrease hair loss.

Will I gain weight during my Xeljanz treatment?

No, you shouldn’t experience weight gain while taking Xeljanz. Weight gain wasn’t a side effect reported in studies of people using this drug.

If you’re concerned about weight gain, talk with your doctor. They should be able to recommend ways to help you manage your weight.

Does Xeljanz cause depression?

No, depression isn’t a side effect of Xeljanz. Depression wasn’t reported in studies of people taking this drug.

However, many people who have autoimmune conditions also have symptoms of depression. If you’re having symptoms of depression, see your doctor right away. They can work with you to find the best treatment options for your depression.

Will stopping my Xeljanz treatment cause any side effects?

It’s possible for symptoms of your condition to return when stopping Xeljanz. For example, if you’re taking Xeljanz for rheumatoid arthritis (RA), discontinuing treatment may cause your RA symptoms to worsen. This is because Xeljanz was working to decrease your symptoms.

This doesn’t happen to everyone who stops taking the drug. If your condition is mild, you may not have worsening symptoms when you stop Xeljanz treatment.

If you want to discontinue Xeljanz treatment, discuss the possibility of worsening symptoms with your doctor. They may recommend other medications to ease your symptoms.

Does Xeljanz cause eye side effects?

No, Xeljanz doesn’t cause eye problems to occur. Eye problems weren’t reported as a side effect in studies of people using Xeljanz.

However, in some rare cases, eye problems may be symptoms of other side effects.

For example, yellowing of your eyes can indicate liver problems, such as hepatitis reactivation. Though rare, hepatitis reactivation is a serious side effect that may occur from taking Xeljanz. For more information about possible liver problems, see the “Side effects explained” section below.

Swelling of the area around your eyes may indicate an allergic reaction. If you have this side effect while taking Xeljanz, talk with your doctor at once. Allergic reactions can be very serious and should be treated immediately. For more information about allergic reaction, see the “Side effects explained” section below.

If you notice yellowing of your eyes or swelling around your eyes, tell your doctor right away. Also tell your doctor if you notice any changes in vision or other eye side effects.

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

Gastrointestinal perforation

It’s possible to develop a gastrointestinal perforation (a tear in the digestive tract) while taking Xeljanz. But this isn’t a common side effect.

Symptoms of gastrointestinal perforation may include:

  • pain in your belly or stomach area
  • change in your bowel movements
  • fever

In many cases, people who developed this side effect while using Xeljanz were also taking nonsteroidal anti-inflammatory drugs (NSAIDs). Examples of NSAIDs include ibuprofen (Advil, Motrin), steroid drugs, and methotrexate (Xatmep, Rasuvo).

What might help

Be sure to talk with your doctor about any medications that you’re taking before you start Xeljanz. Also tell them about any stomach conditions you have. This will help your doctor determine if your medications or your other conditions increase your risk for gastrointestinal perforation.

If you develop any symptoms of gastrointestinal perforation, see your doctor right away. This condition could become very serious, so it’s important to be treated immediately.

Boxed warnings

Xeljanz has several boxed warnings, which are mentioned below. These are the most serious warnings from the Food and Drug Administration (FDA).

Increased risk of blood clots and death

Certain people taking Xeljanz could be at higher risk of developing a blood clot that may be life threatening.

Blood clots are generally a rare side effect. However, they may occur more often in people with rheumatoid arthritis who are:

Higher doses of Xeljanz may increase the risk of developing a blood clot.

What might help

Blood clots can be life threatening. If you develop any symptoms of a blood clot, see a doctor right away.

Symptoms of a blood clot include:

  • severe pain in your chest or leg
  • swelling, redness, or skin discoloration that affects one leg

To prevent blood clots, your doctor will recommend the lowest dose of Xeljanz possible to treat your condition. They’ll also monitor you for signs of a blood clot so that you can get quick treatment if needed.

If you have questions about blood clots and Xeljanz, talk with your doctor.

Serious infections

Although rare, it’s possible to develop a serious infection while taking Xeljanz. This is because Xeljanz may weaken the immune system. Serious infections can be life threatening. If you have symptoms of an infection, such as fever, shortness of breath, or rash, tell your doctor right away.

What might help

Before you start taking Xeljanz, your doctor will test you for tuberculosis (TB). It’s possible to have TB* even if you don’t feel sick or show any symptoms. If you have TB, they’ll recommend treating this infection before you start taking Xeljanz. They’ll also recommend treating any other active infections you have prior to starting Xeljanz.

If you develop symptoms of a serious infection while taking Xeljanz, tell your doctor right away. They may stop treatment with Xeljanz until your infection goes away.

* This is called latent TB. It differs from active TB, also known as TB disease, which makes you feel sick and can be transmitted to others.

Cancer and immune system disorders

Although rare, people taking Xeljanz have developed cancer, such as skin cancer, or immune system disorders. This may be because Xeljanz can weaken your immune system. People who have had kidney transplants may be at higher risk for developing immune system disorders from taking Xeljanz.

What might help

Your doctor will monitor you for symptoms of cancer, such as irregular blood test results or changes in your skin. If you notice any unusual physical changes, be sure to tell your doctor. They will be able to help you determine what is causing these changes.

If you have concerns about developing cancer or an immune system disorder from taking Xeljanz, talk with your doctor.

Changes in blood levels of cholesterol, liver enzymes, or certain blood cells

It’s possible that taking Xeljanz can cause changes in blood levels of certain substances. Your doctor will monitor you throughout your treatment with Xeljanz to watch for such changes.

Increased cholesterol levels

Xeljanz may cause an increase in your cholesterol levels. This side effect, if it occurs, usually happens within the first 6 weeks of treatment.

In studies, this was one of the more common side effects seen in people taking Xeljanz to treat ulcerative colitis.

What might help

Your doctor will monitor your cholesterol levels about 1 to 2 months after you begin Xeljanz. If your cholesterol levels start to increase, they may recommend that you take medication to treat this side effect. Or they may monitor your cholesterol levels more often.

Increased liver enzymes

Although rare, your liver enzyme levels may increase while you’re taking Xeljanz. This increase could indicate liver damage.

Symptoms of liver damage can include stomach pain or yellowing of the eyes or skin. You may be at even higher risk for developing liver damage if you’re also taking methotrexate (Xatmep, Rasuvo).

What might help

Your doctor will recommend liver function tests to monitor your liver throughout Xeljanz treatment. If your liver enzyme levels begin to increase, your doctor may order more blood work. They may also order imaging tests, such as an ultrasound, to see what may be causing this side effect. Or your doctor may recommend you switch to a different medication to treat your condition.

Decreased levels of white blood cells or red blood cells

It’s possible, but rare, that the amount of red or white blood cells you have decreases while taking Xeljanz. A decrease in levels of blood cells may cause certain symptoms, such as infections, feeling weak, or being more tired than usual.

What might help

Your doctor will monitor your blood cell levels 1 to 2 months after starting Xeljanz. Then they’ll check these levels every 3 months while you’re taking Xeljanz.

If your red or white blood cell levels become too low, your doctor may have you stop Xeljanz temporarily. Or they may recommend that you try a different medication for your condition.

Headache

It’s possible to have headaches while taking Xeljanz. Headache is a common side effect that can occur regardless of which condition you’re treating with Xeljanz.

What might help

If you have headaches that are frequent or bothersome, talk with your doctor. They may be able to recommend ways to prevent your headaches from occurring. They may also be able to recommend other medications that you can take to ease your pain.

Diarrhea

Diarrhea is a side effect that you may have when you’re taking Xeljanz. Studies found this to be a common side effect in people taking Xeljanz, regardless of which condition the drug was treating.

What might help

If you’re experiencing diarrhea, talk with your doctor. They may be able to determine if Xeljanz is the cause. They can also suggest options for treating this side effect.

Allergic reaction

Like most drugs, Xeljanz can cause an allergic reaction in some people. In studies of the drug, allergic reaction was a reported side effect.

Symptoms can be mild or serious and can 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. They may suggest an over-the-counter oral antihistamine, such as Benadryl (diphenhydramine), or a topical product, such as hydrocortisone cream, to manage your symptoms.

If your doctor confirms you had a mild allergic reaction to Xeljanz, they’ll decide if you should continue using 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 Xeljanz, they may have you switch to a different treatment.

Keeping track of side effects

During your Xeljanz 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 like:

  • 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 Xeljanz affects you. And your doctor can use this information to adjust your treatment plan if needed.

Xeljanz has several warnings that may affect whether you can safely use it.

Boxed warnings

Xeljanz has several boxed warnings. These are the most serious warnings from the Food and Drug Administration (FDA).

Boxed warnings for Xeljanz include:

  • Increased risk of blood clots and death. When taking Xeljanz, you have an increased risk for developing a blood clot, which may be life threatening. If you have a history of blood clots, talk with your doctor before starting Xeljanz.
  • Serious infections. Xeljanz may weaken your immune system, which can put you at risk for serious infections. If you have an infection, your doctor will recommend treating it before starting Xeljanz.
  • Cancer and immune system disorders. You may be at an increased risk for cancer or immune system problems when taking Xeljanz. Before you start Xeljanz, tell your doctor if you have a history of cancer or immune system problems. You should also tell them if you’ve had a kidney transplant.

To learn more about these boxed warnings, see the “Side effects explained” section above.

Other warnings

Xeljanz 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 Xeljanz. Factors to consider include those below.

Liver problems. On rare occasions, Xeljanz can cause increased liver enzymes. This may be a sign of liver damage. Before taking Xeljanz, be sure to tell your doctor if you have a history of liver problems, such as hepatitis. They may order liver function tests more frequently during your treatment to monitor you. Or they may recommend a different medication to treat your condition.

Allergic reaction. It’s possible to have an allergic reaction while taking Xeljanz. If you’ve had an allergic reaction to Xeljanz or any of its ingredients, you shouldn’t take Xeljanz. Ask your doctor about other medications that might be better options for you.

Kidney problems. If you have any kidney problems, taking the recommended dosage of Xeljanz may result in having too much Xeljanz in your body. This can increase your risk for side effects. If you have any kidney problems, talk with your doctor before starting Xeljanz. They may monitor you for side effects more frequently during your treatment. Or they may recommend a different dose of Xeljanz or another medication altogether.

Stomach problems. Gastrointestinal perforation (a tear in the digestive tract) is a possible side effect of Xeljanz. Stomach problems, such as a history of diverticulitis or ulcers, may increase the risk of this side effect. Xeljanz can also make narrowing or blockages of the digestive tract worse.

Tell your doctor about any stomach problems that you have before you start Xeljanz. They may monitor you more carefully during treatment. Or they may recommend a different medication for your condition.

Conditions affecting your blood cells. Xeljanz may not be right for you if you have certain blood disorders that affect your blood cell counts. Xeljanz can cause low levels of red or white blood cells. If you already have low levels of blood cells, Xeljanz may further decrease these levels. This in turn can increase your risk for infections or anemia.

Before you start taking Xeljanz, your doctor will check your blood cell levels. If your blood cell levels are low, they may recommend a different treatment for your condition. Your doctor will monitor these levels throughout treatment with Xeljanz to be sure that they don’t become too low.

Alcohol use and Xeljanz

Alcohol isn’t known to interact with Xeljanz. However, both alcohol and Xeljanz may cause liver damage. Drinking alcohol while taking Xeljanz may increase your risk for developing liver damage. If you drink alcohol, talk with your doctor about how much is safe to drink while you’re taking Xeljanz.

Pregnancy and breastfeeding while taking Xeljanz

It is not known if Xeljanz is safe to take while pregnant or breastfeeding. There currently isn’t enough information to know if Xeljanz may cause harm to a developing fetus or a breastfeeding child.

Pregnancy

In animal studies of Xeljanz, pregnant animals did have an increased risk for pregnancy loss or birth defects. However, animal studies don’t always predict what will happen in humans.

Two of the conditions Xeljanz treats, rheumatoid arthritis and ulcerative colitis, may cause harm to a developing fetus. If you have any questions about how to treat either condition during pregnancy, talk with your doctor.

If you become pregnant while taking Xeljanz, consider participating in the pregnancy exposure registry for this drug. The pregnancy exposure registry monitors side effects of people who were taking Xeljanz when they became pregnant or throughout their pregnancy. To enroll, call 877-311-8972.

If you’re pregnant or planning to become pregnant, talk with your doctor before taking Xeljanz.

Breastfeeding

In animal studies of Xeljanz, the drug was present in the milk of lactating animals. However, animal studies don’t always predict what will happen in humans.

While taking Xeljanz, you should not breastfeed. If you’re stopping Xeljanz treatment, you should wait at least 18 hours after your last dose before breastfeeding. (If you were taking Xeljanz XR, you need to wait at least 36 hours before breastfeeding.) This is to prevent your child from being exposed to the drug.

If you’re breastfeeding or planning to breastfeed, talk with your doctor before taking Xeljanz.

If you have rheumatoid arthritis, psoriatic arthritis, juvenile idiopathic arthritis, or ulcerative colitis, Xeljanz may help treat your condition. Taking Xeljanz can cause side effects to occur.

Most side effects caused by Xeljanz are mild. However, there are some serious side effects that you should also look out for.

If you have any questions or concerns about side effects that Xeljanz may cause, talk with your doctor or pharmacist. Some examples of questions that you may wish to ask include:

  • How can I manage side effects that I have from Xeljanz?
  • Am I at an increased risk for side effects if I’m also taking other medications with Xeljanz?
  • What should I do if I become pregnant while taking Xeljanz?
  • Due to my personal health history, am I at an increased risk for any specific side effects?

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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 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.