How Olumiant Works

One way that cells in the body communicate with each other is with special signalling proteins called cytokines. Cytokines are made and released by cells and drift around and until they encounter another cell and bind to a receptor on its surface. When a cytokine binds to the surface of a cell, it passes its message to the cell’s nucleus (its “brain” or command centre) using a process called signal transduction. The nucleus responds to a signal by producing the appropriate protein or peptide that’s coded for in its DNA (this is called activation of transcription).

One of the important signal transduction pathways in the body uses an enzyme called Janus Kinase (JAK) and another molecule called Signal Transducer and Activation of Transcription (STAT) to send a signal to a cell’s nucleus. The JAK-STAT pathway is important for sending signals related to bone marrow and immune system activation.

Olumiant is a small molecule that enters a cell and prevents JAK from activating STAT which would then complete the process of sending its signal to the cell’s nucleus.

In rheumatoid arthritis and many other autoimmune disorders, the immune system is not functioning correctly. It attacks the joints the same way it attacks disease-causing germs. By disrupting a key signal sending process related to immune system activation, Olumiant interferes with the ability of immune system cells to talk with each other. When these cells can’t communicate as effectively, they have a hard time coordinating their attack on the joints. The end result is improvement in the symptoms of a patient’s arthritis.

Side Effects of Olumiant

The most common side effects of Olumiant include include upper respiratory tract infections (common cold, sinus infections) and related symptoms. It might also cause nausea. Patients should tell their doctor if these effects are troublesome.

LESS SERIOUS side-effects include:

  • Nausea, indigestion, and diarrhea
  • Upper respiratory tract infection (nasopharyngitis)
  • Cholesterol Levels – Olumiant may increase cholesterol levels. This will be monitored through blood tests

MORE SERIOUS side-effects include:

  • Infection – There have been serious and rare infections associated with the use of Olumiant. Any infections or fevers should be taken very seriously and reviewed by a doctor
  • Blood Counts – Olumiant can cause changes in the numbers of white blood cells (which are needed to fight infection), red blood cells (which carry oxygen), and platelets (which are needed to stop bleeding)
  • Liver – Olumiant may irritate the liver. This does not usually cause symptoms but may be found on blood tests. It is uncommon and usually reversible when regularly monitored with your monthly blood tests
  • Bowels – Olumiant may increase the risk of bowel perforation. This is very rare.
  • Blood Clots – Olumiant may increase the risk of blood clots in the legs (deep venous thrombosis or DVT) or in the lungs (pulmonary embolism or PE). Any new leg swelling or shortness of breath should be taken seriously and reviewed by a doctor.
  • Shingles – Olumiant may increase your risk of developing shingles. Please talk to your doctor about the shingles vaccine.

How to minimize the side-effects of Olumiant:

  • Patients should take the medicine once a day, as prescribed by their doctor
  • Patients should get regular blood tests as requested by their doctor to monitor for side effects, and remember to attend their appointments

Who Should NOT Take Olumiant

Patients should contact their doctor before intentionally missing a dose of Olumiant. However, in the following situations, it would be advisable to stop taking the medicine and call a doctor:

  • Fever
  • An infection or signs of an infection
  • Pregnancy

Patients who are about to have surgery should discuss stopping Olumiant with their doctor.

Some medications may increase the risk of infection and should not be taken with Olumiant, including biologics and other potent immunosuppressive medications.

When to Call a Doctor

Patients taking Olumiant should call their doctor if they feel sick and want to stop, or if they are concerned about any side effects.

Other reasons to call a doctor while taking Olumiant include:

  • Developing a fever or suspected infection
  • Planning for surgery
  • Becoming pregnant or planning on pregnancy
  • Planning on getting any vaccinations
  • New leg swelling or shortness of breath
  • Severe abdominal pain

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