Xeljanz (Tofacitinib) Side Effects By Cristina Mutchler - Verywell Health

Xeljanz (tofacitinib citrate) is a daily oral medication that is approved to treat moderate to severe cases of rheumatoid arthritis (RA), psoriatic arthritis, and ulcerative colitis in adults. Xeljanz is part of a group of medications known as JAK (Janus kinase) inhibitors, which decrease inflammation by helping block an overactive immune response.

Xeljanz is available in a 10 milligram (mg) twice daily dose, and a 5 mg twice daily dose, depending on your condition. It can be used alone or in combination with certain other medications, and is typically prescribed for patients who haven't had success with other classes of drugs.

While Xeljanz can be an effective treatment for some people, there are both mild and serious side effects associated with the drug that you should discuss with your doctor before using.

Grace Cary / Moment / Getty Images

Common Side Effects

Research suggests that RA patients using Xeljanz can experience a significant reduction of their symptoms—such as joint pain, inflammation, and stiffness—and an improvement in their ability to perform daily functions.

According to drug clinical trials, these results can be sometimes be seen in a matter of a few weeks. Despite these positive reports, there are some common side effects associated with taking Xeljanz, which may go away after your body has gotten used to the drug. 

They include:

• Upper respiratory infection, such as the common cold
• Headache
• Diarrhea
• Stuffy or runny nose

Even though they're common, if any of these side effects are severe or don't go away, you should tell your doctor.

In addition, Xeljanz has the potential to increase your cholesterol levels, so your doctor will want to monitor your cholesterol closely while you're taking this medication.

Other routine laboratory tests may also be recommended both before and periodically while taking Xeljanz, as it can cause changes to certain types of white blood cells, hemoglobin, liver enzymes, and lipids.

Serious Side Effects

You should be aware that there are some serious side effects that are linked to taking Xeljanz. This is why your doctor will want to thoroughly go over your personal medical history along with the potential risks and benefits of Xeljanz before prescribing it.

Because Xeljanz is a medication that works on your immune system, it can decrease the body's immune response, which weakens your ability to fight off certain types of fungal, bacterial, or viral infections that could be severe and require hospitalization.

These can range from seemingly minor infections like an open cut, wound, or cold sore, to chronic infections like tuberculosis and hepatitis B or C.

Here are the side effects and symptoms you should pay close attention to:

• Severe fatigue
• Fever or chills
• Yellowing of the skin or eyes
• Loss of appetite
• Stomach pain
• Dark urine
• Clay-colored bowel movements
• Vomiting
• Muscle aches
• Skin rash
• Pale skin
• Shortness of breath or difficulty breathing and swallowing
• Hives or swelling of the face, eyes, lips, or throat

Call your doctor immediately and seek urgent medical care if you experience any of the above side effects while taking Xeljanz.

Warnings

Black Box Warning

Xeljanz has a black box warning, which is the U.S. Food and Drug Administration's (FDA) way of flagging that a drug can have serious and potentially deadly side effects. It's the strongest type of federal safety warning that a medication can carry and still stay on the prescription drug market in the United States.

For Xeljanz, the boxed warning is based on findings from tofacitinib safety trials in RA patients. It alerts physicians and patients to an increased risk of:

• Pulmonary embolism (blood clots in the lungs)
• Death
• Serious infections, including Epstein-Barr virus
• Lymphoma (type of cancer that starts in the blood cells) and other malignancies

It's important to note that the blood clot and death warning is linked to the 10 mg twice daily dose of Xeljanz, which is only approved for ulcerative colitis patients who meet certain condition requirements. The other dosage—5 mg twice daily—is approved for use in RA and psoriatic arthritis patients.

Check with your doctor if you have any questions about the specific warnings, dosages, and increased risks.

Interactions

When considering using Xeljanz, it's especially important to communicate openly with your doctor about all medications you're currently taking and any other medical conditions you may have, as there are several potential interactions to keep in mind.

Make sure to inform your doctor if you're also taking medications for RA, psoriatic arthritis, and ulcerative colitis. You'll probably be advised not to use Xeljanz if you're also taking:

Always take Xeljanz exactly as your doctor has prescribed. Clinical studies show that taking a larger dose of Xeljanz than prescribed has the potential to cause serious heart issues that could potentially be life-threatening.

You should know that Xeljanz could also pose more of a risk to people with certain conditions. In the drug's clinical trials, scientists found that older RA patients with at least one cardiovascular (heart-related) risk factor were more at risk for death. That's why it's essential to tell your doctor if you:

• Are age 50 or older
• Are a smoker
• Have ever been diagnosed with cancer, diabetes, high cholesterol, high blood pressure, HIV or AIDS, liver disease, kidney transplant, lung disease, and any condition that affects your immune system.

In addition, Xeljanz use can interact with vaccinations, so you might want to plan ahead if you need to update any of your routine vaccines. Avoid getting any live-virus vaccines such as the shingles vaccine, nasal flu vaccine Flumist, MMR (measles, mumps, and rubella) vaccine, and yellow fever vaccine.

Experts say inactivated vaccines —such as the flu shot, polio, and hepatitis A vaccines—should be safe to get while taking Xeljanz.

Do not use Xeljanz if you are pregnant, planning to become pregnant, or breastfeeding. Xeljanz is only intended for adult use and is not approved for use in children.

A Word From Verywell

Finding the best medication for you to help manage your RA—or any other medical condition—can sometimes be a frustrating process of trial and error.

The decision to start Xeljanz should not be taken lightly. Your doctor will seriously consider several factors, including how old you are, how severe your RA is, and if you have any other medical conditions that could impact its use.

Together, you can weigh whether the benefits Xeljanz override any potential serious side effects. Seek medical attention immediately if you experience any severe symptoms or complications while taking Xeljanz.