How long does Aducanumab-avwa Injection stay in your system?
Last updated September 7, 2026.
Aducanumab-avwa leaves the body slowly, with a half-life of about 25 days, so roughly 4 to 5 months pass after your last infusion before the drug is essentially gone. It is a monoclonal antibody given as an intravenous infusion every 4 weeks, and it is broken down the way your body handles other large proteins rather than by the liver enzymes or kidneys that clear most pills. Because each dose arrives before the previous one is cleared, blood levels rise over the first several months and then level off. Body weight and the presence of anti-drug antibodies can shift how much drug stays in circulation, so two people on the same schedule may not match exactly. Brain MRI findings such as ARIA can appear or persist while the antibody is still present, which is why scans are often continued for a period after the last dose. Keep a written record of your infusion dates and MRI results, and bring it to any new clinician or emergency visit.
What to do
- Count from your last infusion: Mark the date of your final dose and expect about 4 to 5 months before the drug is essentially cleared.
- Keep the MRI schedule: Continue any brain MRI monitoring your neurologist ordered, even after infusions have stopped.
- Report new symptoms promptly: New headache, confusion, dizziness, vision changes, nausea, or trouble walking need same-day medical review, since these can signal ARIA.
- Flag it before other treatments: Tell any clinician considering a blood thinner or clot-busting drug that you received an anti-amyloid antibody and when.
- Carry your infusion record: A card or phone note with dose dates, your APOE genotype if known, and recent MRI results speeds up care in an emergency.
- Ask about what comes next: Since Aduhelm is no longer marketed, ask your neurologist whether a different anti-amyloid treatment or supportive care fits your situation.
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