M Toronto Myositis Centreat St. Michael's Hospital
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Tofacitinib

Xeljanz · say “toe-fa-SYE-ti-nib”
JAK inhibitor
iUsed in myositis based on specialist experience and evidence, not a formal Canadian myositis approval.
i
You are checked before you start.

Like other JAK inhibitors, you are tested for tuberculosis and shingles risk first. Your blood counts and cholesterol are watched while you take it.

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What it is

A targeted pill for stubborn disease.

Tofacitinib is a JAK inhibitor. It is a tablet that blocks signals inside immune cells that cause inflammation. At the Centre it may be used for inflammatory disease, and for some people with dermatomyositis whose skin or muscle disease has not settled with other medicines. It is used in myositis based on specialist experience, not a formal Canadian myositis approval.

How to take it
  • Usually one 5 mg tablet twice a day, or one 11 mg slow-release tablet once a day. Follow your exact prescription.
  • Take with or without food, at about the same time each day.
  • Swallow the tablet whole. Do not crush or split it.
  • If you miss a dose, take it when you remember, unless the next dose is close. Never take two at once.
What to expect
  • It works over weeks. Some people feel better sooner.
  • Take it every day. It works best when taken steadily.
  • Do not stop because it feels slow. The full effect builds over time.
Benefits

How it helps you.

Calms skin and muscle inflammation

Can help dermatomyositis rashes and muscle disease that other medicines have not settled.

A simple pill

Taken by mouth, with no needles and no fridge.

An option when others fall short

Useful when first-line medicines have not been enough.

Steroid-sparing

May let your doctor lower your prednisone.

Works day to day

Steady daily dosing keeps inflammation in check.

Risks & side effects

What you should know.

Your doctor chose this because the likely benefits outweigh the risks for you. Here is the honest, full picture.

Common side effects
Cold and sinus infections
The most common effect. Treat like a normal cold, and call if it gets worse or lingers.
Headache
Can happen, especially early.
Nausea
Some mild queasiness. Taking it with food may help.
Higher cholesterol
Your cholesterol may rise. It is checked and treated if needed.
Acne
Some new spots, usually mild.
Serious but uncommon
Serious infections
It calms the immune system, so infections can happen, including tuberculosis (TB). You are tested for TB before you start.
Shingles
A painful blistering rash. The risk is higher with this class, so the shingles vaccine is advised.
Blood clots
Rarely, clots in a leg or lung. Report new leg swelling, chest pain, or breathlessness right away.
Heart and cancer risk
In people over 50 who smoke or have heart risks, there is a small rise in heart events and some cancers, so screening continues.
Staying safe

Monitoring and precautions.

Regular monitoring
  • Blood counts, liver, and cholesterol are checked on blood tests.
  • A TB test and chest X-ray are done before you start.
  • Cancer screening (skin checks and others) is kept up to date.
Everyday precautions
  • Get the shingles vaccine before or soon after starting.
  • Avoid live vaccines. Flu and COVID vaccines are safe.
  • Do not smoke, which adds to heart and cancer risk with this class.
  • Tell your doctor about any new medicine, and use sun protection.
When to call your doctor

Contact the clinic if you notice:

Fever or signs of infection
Any fever, chills, cough, or painful urination that needs treatment.
A shingles rash
A painful, blistering rash, often on one side. Report it quickly.
Leg swelling or chest pain
New swelling in one leg, chest pain, or trouble breathing may be a clot. Seek care.
Before starting a new medicine
Some drugs interact with tofacitinib. Check first.
Planning pregnancy
Talk with your doctor before trying, since it may harm a baby.

Pregnancy & breastfeeding

Tofacitinib may harm an unborn baby. Do not take it if you are pregnant or trying to become pregnant, and use reliable birth control while on it. Do not breastfeed while taking it. Talk with your doctor before planning a family.

!

This guide is for learning, not medical advice. Myositis care is different for everyone, and many of these medicines are used based on specialist experience rather than a formal Canadian myositis approval. Never start, stop, or change a medicine without your own doctor. Your doses are decided with your care team at the Centre.

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