9 Xeljanz Side Effects You Should Know About

Xeljanz (tofacitinib) is a Janus kinase (JAK) inhibitor that’s prescribed to treat a variety of autoimmune disorders. These disorders include rheumatoid arthritis, ankylosing spondylitis, and ulcerative colitis, among others.

Xeljanz works to treat these conditions by suppressing (weakening) the immune system. But this can also cause side effects.

Xeljanz side effects at a glance

JAK inhibitors, such as Xeljanz, have many possible side effects. Some are mild and can be managed at home. Others are serious and may require medical treatment.

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Common Xeljanz side effects include:

• Upper respiratory tract infections (URTIs)

• Cold-like symptoms, such as sore throat and runny nose

• Diarrhea

• Headache

• Raised cholesterol

• Raised blood pressure

• Nausea

Rare but serious Xeljanz side effects include:

• Serious infections, such as pneumonia and shingles

• Higher risk of cancer

• Heart attack

• Stroke

• Blood clots

• Damage to the stomach or intestine

• Severe allergic reactions

Below, we’ll discuss what you need to know about nine notable Xeljanz side effects.

1. Upper respiratory infections

URTIs, including sinus infections and the common cold, are a common Xeljanz side effect. These infections may lead to symptoms like sore throat, a stuffy or runny nose, or sneezing. Other symptoms, like fever and body aches, are also possible.

Many URTIs are caused by viruses, which means they should go away on their own. They don’t usually need to be treated with antibiotics. Though, if you have a URTI that’s caused by bacteria, your healthcare provider may prescribe you an antibiotic.

You can usually treat the symptoms at home with some simple techniques. Staying hydrated and getting enough sleep can both be helpful. You can also take over-the-counter (OTC) cold medication if it’s OK with your provider. Reach out to your care team if your symptoms don’t go away after about 1 week or get worse after you’ve tried to treat them at home.

2. Diarrhea

Diarrhea is another common Xeljanz side effect. But keep in mind that diarrhea can have many causes and may be related to the condition you’re treating (e.g., ulcerative colitis). So it may not be caused by Xeljanz in all cases.

Mild diarrhea can be treated at home. But you may need medical attention if you have severe diarrhea.

Home treatments for diarrhea can include diet changes, like avoiding fatty or fried foods and eating a bland diet for a short period of time. It’s also a good idea to make sure you’re well hydrated to prevent dehydration. OTC medications like loperamide (Imodium A-D) may be helpful, but check with your healthcare provider first.

3. Headache

While taking Xeljanz, you could experience headaches. Like other common Xeljanz side effects, mild headaches can be managed at home. Simple strategies like reducing stress through mindfulness, drinking enough water, and regularly exercising may help. Getting enough sleep and being careful about your caffeine intake are also good steps to take for headache relief.

If you’re still having problems with headaches after trying these strategies, you may need an OTC pain reliever, such as acetaminophen (Tylenol). If your headaches are severe or aren’t going away, let your healthcare provider know. They may suggest adjusting your medication regimen or taking a prescription-only medication to help treat or prevent headaches.

4. Raised cholesterol

Cholesterol is a type of fat that your body needs. But too much cholesterol can increase your risk for blood vessel blockages, which can lead to serious heart-related problems. In clinical studies of Xeljanz, people taking the medication developed higher cholesterol levels. But researchers aren’t sure if cholesterol changes related to Xeljanz significantly impact the risk of heart-related complications.

Your healthcare provider will likely check your cholesterol levels from time to time while you’re taking Xeljanz. If your cholesterol becomes too high, they may recommend that you switch to a different treatment or take medication to lower your cholesterol.

5. Serious infections

Xeljanz can raise the risk of serious infections because it lowers your immune response. All JAK inhibitors carry a boxed warning (the FDA’s most serious warning for medications) about serious infections. These infections can be caused by bacteria, viruses, or fungi. Infections that have been reported by people taking Xeljanz include pneumonia, shingles, and appendicitis.

You shouldn’t take Xeljanz if you have a serious, active infection. You also may need to avoid Xeljanz if you have a history of serious infections or a health condition that raises your risk for infection.

You should watch for symptoms of an infection while you’re taking Xeljanz. This includes fever, chills, and coughing. If you have any of these symptoms, let your healthcare provider know.

6. Damage to the stomach and intestines

While taking Xeljanz, it’s possible to have damage or tears in the lining of your stomach or intestines. However, many people who experienced this side effect in clinical studies were also taking nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil, Motrin), or corticosteroids, such as prednisone. And these medications can also cause damage to the stomach and intestines.

If you have new stomach pain or discomfort while taking Xeljanz, let your healthcare provider know. Your provider may want to check for possible damage or tears in your stomach or intestines. Depending on your individual risk factors, they may also recommend taking medication to help protect your stomach and intestines.

7. Blood clots

Blood clots are another serious potential Xeljanz side effect. Blood clots in the brain (stroke) or lungs (pulmonary embolism) can be life-threatening. But serious clots can also happen in your legs or arms. The risk of blood clots is included in the boxed warning for Xeljanz.

Redness, warmth, or pain in your leg or arm could indicate the presence of a blood clot. If you develop any of these symptoms, contact your healthcare provider right away.

Trouble breathing, chest pain, or weakness on one side of the body could mean you have a blood clot in the lungs or brain. If you experience any of these symptoms, get help right away by calling 911 or going to the nearest emergency room.

Let your provider know if you have a history of blood clots. They may avoid prescribing you Xeljanz if you have a higher risk of clots.

8. Heart attack or stroke

Heart attack and stroke are other rare but serious Xeljanz side effects that are mentioned in the medication’s boxed warning. In clinical studies, people taking Xeljanz had higher rates of heart attack and stroke compared to those taking biologic medications. However, the risk of these serious side effects is very small.

Your healthcare provider will carefully consider your risk for heart attacks and stroke before prescribing you Xeljanz. And they may recommend a different medication, depending on the risk.

9. Higher risk of cancer

A higher risk of cancer is also included in the boxed warning for Xeljanz. In clinical studies, people taking Xeljanz had a higher rate of several types of cancer compared to people taking biologic medications like Humira (adalimumab). But keep in mind that the risk of developing cancer related to Xeljanz is still very low.

Your healthcare provider can help you determine your risk for cancer and whether you should avoid taking Xeljanz. If you already have cancer or develop cancer while taking Xeljanz, your provider will help you weigh the risks and benefits of either continuing or stopping treatment with the medication.

When should I contact my healthcare provider about Xeljanz side effects?

You can contact your healthcare provider whenever you have questions about Xeljanz side effects. Your pharmacist can also be a helpful resource. Remember that many mild side effects can be safely handled at home.

If you’re experiencing symptoms of severe side effects, get help right away. These symptoms include:

• High fever and other signs of an infection, like fatigue or chills

• Severe headaches or dizziness

• Sudden confusion or slurred speech

• Weakness or numbness on one side of your body

• Shortness of breath or chest pain

• Sudden warmth, redness, or pain in your leg or arm

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Written by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

Edited by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

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