Safety and Side Effects

A serious and the most common side effect of ADUHELM is called “ARIA.”

41% of people taking ADUHELM in 2 clinical studies had ARIA-E and/or ARIA-H
compared to 10% of people who took placebo.

• Some people with ARIA had headache, nausea, confusion, difficulty walking, dizziness, seizures, and vision changes
• Some people with ARIA did not have symptoms
• Talk to your doctor if you have symptoms
• Some people have a genetic risk factor (homozygous apolipoprotein E gene carriers) that may cause an increased risk for ARIA. Talk to your healthcare provider about testing to see if you have this risk factor
• Some medicines may increase the risk for larger areas of bleeding in the brain in patients taking ADUHELM. Talk to your healthcare provider to see if you are on any medicines that increase this risk
• Call your healthcare provider or go to the nearest hospital emergency room if you have any of the symptoms listed above

Another serious side effect is:

• Serious allergic reactions. Swelling of the face, lips, mouth, or tongue and hives have happened during an ADUHELM infusion. Tell your healthcare provider if you have any of the symptoms of a serious allergic reaction during or after ADUHELM infusion.

Other most common side effects besides ARIA are headache and fall.

Whether you have symptoms of ARIA or not, your doctor will:

• Do a brain scan before you start ADUHELM
• Do 4 more brain scans, before your 5th, 7th, 9th, and 12th infusions of ADUHELM, to check for ARIA
• Decide if you should have more brain scans, particularly as your doses increase in the first 8 months of treatment
• Do these brain scans by magnetic resonance imaging, or MRI

If your MRI brain scan shows ARIA and/or you have symptoms that are possibly related:

• Your doctor should carefully monitor you
• Your doctor may choose to stop or pause treatment with ADUHELM
• Your doctor will watch to see if ARIA goes away
• Your doctor will talk to you about whether you can continue to take ADUHELM