M Toronto Myositis Centreat St. Michael's Hospital
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Mycophenolate

CellCept, Myfortic · say “My-co-FEE-no-late”
Immunosuppressant
iUsed in myositis based on specialist experience and evidence, not a formal Canadian myositis approval.
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Not in pregnancy.

Mycophenolate causes serious birth defects and miscarriage. Do not take it if you are pregnant or planning pregnancy, and use two reliable forms of contraception while on it.

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What it is

A steroid-sparing immunosuppressant.

Mycophenolate calms an overactive immune system. In autoimmune diseases like myositis, lupus, and vasculitis, the immune system mistakenly attacks healthy tissue; mycophenolate reduces that harmful activity to control inflammation and help prevent organ damage. It has been used for decades in rheumatology and transplant medicine, and it lets your doctor lower your steroid dose over time.

How to take it
  • CellCept (mycophenolate mofetil) comes as 500 mg tablets, 250 mg capsules, or a liquid. Usual dose is 500 to 1500 mg twice daily.
  • Myfortic (mycophenolate sodium) comes as 180 mg and 360 mg enteric-coated tablets, which may be gentler on the stomach.
  • Take twice daily, about 12 hours apart, at consistent times. CellCept absorbs best on an empty stomach; Myfortic can be taken with or without food.
  • Swallow tablets whole. Do not crush, chew, or break them, and do not switch between CellCept and Myfortic without your doctor, as they are not interchangeable milligram for milligram.
  • If you miss a dose, take it when you remember unless the next dose is near; never double up.
What to expect
  • It takes 6 to 12 weeks to reach full effect. Do not stop because it seems slow.
  • Take it consistently, since skipping doses reduces its effect and can trigger a flare.
  • You can stop it without tapering if needed, but always speak with your doctor first.
Benefits

How it helps you.

Controls disease activity

Reduces inflammation in myositis, lupus, vasculitis, and related conditions to bring disease under control.

Protects vital organs

A first-line treatment when the kidneys are involved, and helpful when the lungs are affected.

Reduces flares

Once disease is controlled, it helps prevent the unpredictable return of symptoms.

Steroid-sparing

Lets your doctor lower your prednisone, reducing long-term steroid effects such as weight gain and bone loss.

Well studied and widely used

A long track record in rheumatology and transplant medicine.

Convenient oral dosing

Taken as a pill twice daily, with no injections, in several strengths for flexible dosing.

Risks & side effects

What you should know.

Your doctor prescribed this because the expected benefits outweigh the risks for your situation. Here is the honest, full picture.

Common side effects
Stomach upset
Nausea, diarrhea, or indigestion are the most common effects. Taking with food or switching to Myfortic can help.
Headache or dizziness
Some people notice headaches, dizziness, or trouble sleeping early on, which usually improve.
Higher infection risk
Because it lowers immune activity, colds, flu, and urinary infections can be more likely.
Low blood counts
White cells, red cells, or platelets may drop. Monitored with blood tests and managed by dose.
Serious but uncommon
Serious infections
Rarely, severe or unusual infections. Report any fever, chills, or signs of infection and stop the medication.
PML (brain infection)
Very rarely, a serious brain infection. Report new confusion, vision changes, weakness, or trouble with speech or balance.
Cancer risk
Long-term use carries a small increased risk of skin cancers and lymphoma. Use sunscreen and attend skin checks.
Liver effects
Rarely affects liver function, detected by routine blood tests.
!
Pregnancy warning.

Mycophenolate causes serious birth defects and miscarriage. Do not take it if you are pregnant or planning pregnancy. Use two reliable forms of contraception while on it and for 6 weeks after stopping, and discuss family planning with your doctor first.

Staying safe

Monitoring and precautions.

Regular monitoring
  • Blood tests (CBC and liver function), often every 2 to 4 weeks at first, then less often once stable.
  • Blood counts are watched, since mycophenolate can lower white cells (infection risk) and platelets (bleeding risk).
  • Liver enzymes are checked periodically.
  • Kidney function is monitored, and doses may be adjusted if you have kidney disease.
Daily precautions
  • Avoid live vaccines. Stay current on flu and COVID vaccines before starting where possible, and household contacts should avoid live oral polio vaccine.
  • Use SPF 30+ sunscreen and report new or changing skin spots, since long-term use can raise skin-cancer risk.
  • Practice food safety: avoid raw or undercooked meats and unpasteurized dairy.
  • Do not handle crushed or broken tablets; if one breaks, avoid inhaling the dust or getting it on your skin.
  • Wash hands often and avoid close contact with people who are sick.
When to call your doctor

Contact the clinic if you notice:

Fever or signs of infection
Any fever, chills, persistent cough, sore throat, painful urination, or unusual fatigue. Stop and call promptly.
Stomach upset
Nausea, vomiting, or diarrhea that is severe or persistent. Your doctor may adjust the dose or switch to Myfortic.
Unusual bleeding or bruising
Easy bruising, bleeding from cuts, or blood in urine or stool may signal low blood counts.
Neurological changes
New confusion, vision changes, trouble with balance or speech, or progressive weakness. Report urgently.
Before any vaccination or surgery
Check first, since live vaccines are not safe and the medication may need pausing around surgery.
Planning pregnancy
Contact your doctor before conceiving, since mycophenolate must be stopped well beforehand.

Pregnancy & breastfeeding

Mycophenolate must not be used in pregnancy. It causes serious birth defects and miscarriage. Use two reliable forms of contraception while taking it and for 6 weeks after stopping. If you are planning a family, your doctor will switch you to a pregnancy-safe medication first.

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This guide is for education, not medical advice. Myositis treatment is individual, and many of these medications are used based on specialist experience and research rather than a single approval for myositis. Never start, stop, or change a medication without your own doctor. Your doses and choices are decided with your care team at the Centre.

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