Xeljanz Side Effects & Safety

The safety of Xeljanz in patients with RA has been evaluated in several clinical studies, including two Phase 2 and five Phase 3 randomized, controlled trials, in which patients were randomized to Xeljanz 5 mg and 10 mg twice daily as monotherapy (alone) (292 and 306 patients, respectively), and Xeljanz 5 mg and 10 mg twice daily in combination with disease-modifying anti-rheumatic drugs (DMARDs) including methotrexate (1,044 and 1,043 patients, respectively) and placebo (809 patients). Two long-term safety studies were conducted and included patients who had participated in blinded, controlled trials. The most common serious side effects with Xeljanz were serious infections. The percentage of patient who discontinued Xeljanz due to any adverse reaction during blinded, controlled trials was 4% compared with 3% for patients who received placebo. The most common side effects that occurred in at least 2% of Xeljanz patients and at least 1% greater than in placebo patients included diarrhea, nasopharyngitis, upper respiratory tract infections, headache, and hypertension.1


Most common side effects occurring in two Kineret RA clinical trials*

Side effect Kineret 100 mg/day + DMARD** (N=1,565) Placebo + DMARD** (N=733)
Injection site reaction 71% 29%
Worsening RA 19% 29%
Upper respiratory tract infection 14% 17%
Headache 12% 9%
Nausea 8% 7%
Diarrhea 7% 5%
Sinusitis 7% 7%
Arthralgia 6% 6%
Flu-like symptoms 6% 6%
Abdominal pain 5% 5%
*Occurring in at least 5% of patients who received treatment for 6 months.
**Included disease-modifying antirheumatic drugs (DMARDs) methotrexate, sulfasalazine, hydroxychloroquine, gold, penicillamine, leflunomide, and azathioprine.


Precautions and warnings

There are several warnings and precautions related to Xeljanz that you should be aware of before starting treatment.


Serious infections. There is an increased risk for developing serious infections with Xeljanz, including tuberculosis (TB), bacterial, viral, invasive fungal (fungal infection inside the body, such as histoplasmosis), and other opportunistic infections (infections that result from microorganisms that normally do not cause diseases in humans). The increased risk of infection with Xeljanz occurs because the drug can decrease the ability of the immune system to fight infections. If you develop a serious infection while taking Xeljanz, you should interrupt treatment until the infection is controlled. You should not take Xeljanz while you have an active infection.1

Before starting treatment with Xeljanz, you should be tested for latent TB, and, if positive, you should receive treatment for TB before starting Xeljanz. All patients (even those with an initial negative TB test) should be monitored for active TB during treatment with Xeljanz.1

The signs of TB include a cough that persists, a low-grade fever, weight loss, and loss of body fat and muscle.


Cancer. Lymphoma and other cancers have been reported in patients who received treatment with Xeljanz. While the risk for developing these cancers with Xeljanz is small, it does exist and should be considered before receiving Xeljanz.1


Pregnancy and nursing

Xeljanz is a pregnancy category C drug. In animal studies, Xeljanz did result in birth defects in the developing fetus. There have been no well-controlled studies in humans. Xeljanz should only be used in pregnant women if the potential benefits justify the risk to the fetus.

It is unknown whether Xeljanz is excreted into human milk. Because of the potential for adverse effects to the nursing infant, a nursing woman should either stop taking the drug or discontinue nursing while taking Xeljanz.1


Drug interactions

Patients should not receive live vaccines while taking Xeljanz.1

Taking Xeljanz together with other drugs may influence the way your body metabolizes Xeljanz or these other drugs. Drugs that interact in this way with Xeljanz include the anti-fungal drugs ketoconazole (used to treat fungal skin infections) and fluconazole (used to treat systemic and superficial fungal infections), and the antibiotic drug rifampin (used to treat TB).1

The safety of using Xeljanz in combination with immunosuppressive drugs (examples include azathioprine and cyclosporine) has not been studied. However, the combination of Xeljanz and these drugs may increase immunosuppression and the risk for infection.1

Written by: Jonathan Simmons | Last reviewed: September 2013.