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Aducanumab Side Effects

Medically reviewed by Last updated on May 19, 2022.

Applies to aducanumab: intravenous solution.

Serious side effects of Aducanumab

Along with its needed effects, aducanumab may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking aducanumab:

More common

  • Blurred or changes in vision
  • confusion
  • confusion as to time, place, or person
  • dizziness
  • falls
  • hallucinations
  • headache
  • holding false beliefs that cannot be changed by fact
  • mental depression or anxiety
  • nausea
  • nightmares or unusually vivid dreams
  • problems with movement, walking, or speech
  • seizures
  • sleepiness or unusual drowsiness
  • unusual excitement, nervousness, or restlessness
  • vomiting

Incidence not known

  • Hives, welts, or itching
  • large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • redness of the skin

Other side effects of Aducanumab

Some side effects of aducanumab may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

For Healthcare Professionals

Applies to aducanumab: intravenous solution.


The most commonly reported adverse reactions have included amyloid related imaging abnormalities, headache, and falls.[Ref]

Nervous system

In clinical studies ARIA-E or ARIA-H were observed in 41% of patients treated (454 out of 1105), compared to 10% of patients on placebo (111 out of 1087). ARIA-E was observed in 35% of patients treated at 10 mg/kg, compared to 3% of patients on placebo. The incidence of ARIA-E was higher in apolipoprotein E4 (ApoE4) carriers than in ApoE4 non-carriers (42% and 20%, respectively). The majority of ARIA-E radiographic events occurred early in treatment (within the first 8 doses). Radiographic severity for ARIA-E was mild (30%), moderate (58%), and severe (13%); resolution occurred in 68% of patients by 12 weeks, 91% by 20 weeks, and 98% overall after detection. The manufacturer's product labeling can be consulted for definitions of severity. ARIA-H in the setting of ARIA-E was observed in 21% of patients compared to 1% of patients on placebo. Clinical symptoms were present in 24% of patients with ARIA compared to 5% of patients on placebo and included: headache (13%), confusion/delirium/altered mental status/disorientation(5%), dizziness/vertigo (4%), visual disturbance (2%), and nausea (2%).

Very common (10% or more): Amyloid related imaging abnormalities-edema (ARIA-E; 35%); headache (21%); ARIA-hemosiderin deposition microhemorrhage (19%); ARIA-H superficial siderosis (15%), clinical symptoms of ARIA (25%, included: headache, confusion/delirium/altered mental status/disorientation, dizziness/vertigo, visual disturbance, and nausea)


Very rare (less than 0.01%): Angioedema, urticaria


Common (1% to 10%): Confusion/delirium/altered mental status/disorientation

The occurrence of confusion/delirium/altered mental status/disorientation appears to be due to symptomatic ARIA.


Very common (10% or more): Fall (15%)


Common (1% to 10%): Diarrhea


Uncommon (0.1% to 1%): Anti-aducanumab antibodies


1. "Product Information. Aduhelm (aducanumab)." Biogen Idec Inc (2021):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.