M Toronto Myositis Centreat St. Michael's Hospital
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IVIG

intravenous immune globulin · say “I-V-I-G”
Immune-adjusting blood product
iUsed in myositis based on specialist experience and evidence, not a formal Canadian myositis approval.
i
Given by infusion over 2 to 6 hours.

IVIG is given monthly by an IV drip over several hours. Drink plenty of water the day before and after each infusion to protect your kidneys.

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What it is

Proven in dermatomyositis, without weakening immunity.

IVIG is a purified solution of antibodies collected from thousands of healthy blood donors. In myositis and dermatomyositis it adjusts your immune system, blocking the harmful autoantibodies that attack your muscles and skin and resetting the pathways that drive inflammation. Unlike immune-suppressing medicines, IVIG does not significantly weaken your immune defences, and it is one of the few treatments with strong clinical-trial evidence specifically in dermatomyositis.

How to take it
  • Given by IV infusion through a vein in your arm, by a trained nurse in an infusion centre or hospital.
  • Each infusion takes 2 to 6 hours, started slowly and increased gradually as you tolerate it.
  • The standard myositis dose is 2 g/kg divided over 2 to 5 consecutive days each month (about 140 g total for a 70 kg person).
  • Cycles are usually repeated monthly for 3 to 6 months, then reassessed based on your response.
What to expect
  • Some people improve within the first 1 to 2 cycles; others need 3 to 6 months.
  • CK often drops before strength improves. Your doctor tracks both.
  • Dermatomyositis rashes may also improve.
  • It is often used alongside other immune-suppressing medicines and during steroid tapering.
Benefits

How it helps you.

Improves muscle strength

Directly addresses the immune attack on muscle, often improving rising from chairs, stairs, and lifting.

Clears resistant skin rashes

Effective for stubborn dermatomyositis rashes: heliotrope, Gottron’s papules, V-sign, and mechanic’s hands.

Does not suppress immunity

Modulates rather than suppresses the immune system, so infection risk is significantly lower.

Steroid-sparing

Allows prednisone tapering, valuable for people who have struggled to come off steroids.

Treats swallowing difficulty

Can improve dysphagia caused by myositis affecting the throat muscles, a serious complication.

Safe in pregnancy

One of the safest immune therapies in pregnancy, useful for managing flares.

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
Headache
The most common effect, usually within 24 to 48 hours. Hydration and acetaminophen help; it can trigger migraines.
Fever and flu-like symptoms
Chills, fatigue, and aches for 24 to 48 hours after infusion. Pre-medications reduce this.
Infusion reactions
Flushing, nausea, back pain, or blood-pressure changes during the infusion. Slowing the rate usually resolves these.
Fatigue
Feeling tired for 1 to 2 days is common. Plan a rest day after each infusion.
Serious but uncommon
Aseptic meningitis
Severe headache with neck stiffness, light sensitivity, and nausea. Rare, needs urgent evaluation, usually resolves.
Blood clots
IVIG can thicken the blood. Report new leg swelling, calf or chest pain, or sudden breathlessness. Higher risk with cardiovascular risk factors.
Kidney injury
Rarely. Hydration before and after helps protect the kidneys, and blood tests monitor this.
Allergic reaction
Rare but serious. Hives, throat tightness, wheezing, or feeling faint during infusion. Alert the nurse immediately.
Staying safe

Monitoring and precautions.

Regular monitoring
  • Baseline blood tests before starting, including IgA levels (low IgA raises reaction risk), CBC, and kidney and liver function.
  • CK levels are tracked to follow your disease activity and response.
  • Blood pressure and vital signs are monitored before, during, and after each infusion.
  • Kidney function is checked periodically.
Daily precautions
  • Hydrate well the day before, the morning of, and for 24 to 48 hours after each infusion.
  • Pre-medications (typically acetaminophen and an antihistamine) are given to reduce reactions.
  • Tell the infusion nurse about any past reactions, so the rate can be adjusted.
  • You can receive vaccines as normal, since IVIG does not significantly suppress immunity (discuss timing with your doctor).
  • Plan a rest day after each session and avoid strenuous activity on infusion day.
When to call your doctor

Contact the clinic if you notice:

Severe or persistent headache
Common, but a severe headache with neck stiffness or light sensitivity may signal aseptic meningitis. Seek care.
Breathlessness or chest pain
Trouble breathing or chest pain during or after infusion may indicate a clot. Report immediately.
New leg swelling
Swelling, warmth, or pain in a leg may indicate a clot. Report promptly.
Reduced or dark urine
May reflect the kidneys. Report a significant drop in urination or dark, foamy urine.
Any reaction during infusion
Hives, flushing, back pain, rapid heartbeat, or faintness. Alert the infusion nurse immediately.
Fever or signs of infection
Chills or persistent fever should be evaluated.

Pregnancy & breastfeeding

IVIG is considered safe during pregnancy and breastfeeding, which makes it a valuable option for managing myositis flares in pregnant patients. Discuss timing with your doctor.

!

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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