This medication may increase your risk of serious (possibly fatal) side effects such as temporary swelling of the brain, or small spots of bleeding in or on the surface of the brain. These side effects are also known as amyloid-related imaging abnormalities (ARIA). Your doctor may order a genetic test to measure your risk for ARIA before you start this medication. If the genetic test shows you are at greater risk, your doctor should discuss with you the risks and benefits of starting aducanumab. Your doctor will do magnetic resonance imaging (MRI) scans before and during treatment to check for these side effects. If you are also taking medications that can cause bleeding/bruising (including antiplatelet drugs such as clopidogrel, NSAIDs such as ibuprofen/naproxen, "blood thinners" such as warfarin/dabigatran), your doctor will monitor you more closely for bleeding. ARIA usually go away over time. They do not always cause symptoms, but tell your doctor right away if you develop symptoms such as headache, dizziness, nausea, confusion, seizures, trouble walking, or vision changes.