Janus Kinase Inhibitor Overview
Xeljanz is a Janus kinase inhibitor (JAK inhibitor) prescribed to treat patients with arthritis or ulcerative colitis.
Generically known as tofacitinib citrate, Xeljanz has been the subject of a new Food and Drug Administration warning regarding increased risks of blood clot injuries.
FDA Warning to Rheumatoid Arthritis Patients
In late February 2019, the FDA issued a Xeljanz warning that patients with rheumatoid arthritis who were taking 10mg twice a day of the drug had an increased risk of blood clots in the lungs and death.
The FDA has only approved 10 mg twice a day to treat patients with ulcerative colitis; the FDA has approved 5 mg twice a day to be given to patients with rheumatoid arthritis.
The warning was issued after a clinical safety trial found the increased danger for patients with rheumatoid arthritis who were given 10 mg twice a day. The patients in the safety clinical trial are being transitioned to the lower dose of 5 mg twice daily.
“Health care professionals should follow the recommendation in the tofacitinib prescribing information for the specific condition they are treating,” said the FDA.
Blood Clots and JAK
Those taking too much Xeljanz should be aware of the symptoms of a blood clot in the lungs, also known as a pulmonary embolism. Symptoms can include:
- Sudden shortness of breath or difficulty breathing
- Chest pain or pain in the back
- Coughing up blood
- Excessive sweating
- Clammy or blush-tinged skin color
A blood clot in the lungs can be life-threatening and nearly a third of patients who aren’t treated properly succumb to the pulmonary embolism. Patients who are at a higher risk for blood clots in the lungs include those with heart disease, certain types of cancer, recent surgery, or prolonged bed rest.
A pulmonary embolism is a blood clot that blocks one of the pulmonary arteries in the lungs. Most of the time, the blood clots have traveled to the lungs from the legs or other parts of the body.
Mechanism of JAK Inhibitor Xeljanz
Xeljanz works by suppressing the activity of the immune system. It helps fight rheumatoid arthritis and ulcerative colitis because both are diseases that cause chronic inflammation.
Xeljanz is a Janus kinase inhibitor (JAK inhibitor), which means it interferes with the JAK signaling pathway found inside cells that induce inflammation.
JAK inhibitors belong to a class of drugs known as small molecule DMARDS (disease-modifying anti-rheumatic drugs), which means they do not belong to the biologics drug class. The difference is that small molecule DMARDS work inside the cell’s structure; biologics work with the receptors on the surface of cells.
Other Side Effects of Xeljanz
Because Xeljanz suppresses the immune system, the patient is more vulnerable to infection and infectious diseases. Fever, chills, fatigue, constant sore throat, persistent cough and night sweats can all indicate the patient is fighting infection.
Other side effects may include headaches or diarrhea. Serious side effects may include unusual fatigue, fast heartbeat, shortness of breath, abdominal pain, or signs of liver problems.
