What are the FDA‑approved treatments for Alzheimer’s and what do they do?

1. Disease‑modifying antibodies: what’s approved and how they work

Lecanemab (Leqembi®) and donanemab (Kisunla™) are intravenous monoclonal antibodies approved to treat adults with early Alzheimer’s disease (mild cognitive impairment or mild dementia) who have confirmed amyloid pathology; both reduce amyloid‑beta plaques in the brain and have been shown in randomized trials to slow cognitive and functional decline modestly over about 18 months ^{[1] [3] [5]}. Lecanemab was converted from accelerated to traditional approval after a confirmatory Phase 3 trial verified clinical benefit, and donanemab received full FDA approval with trial evidence of slowed clinical decline and amyloid clearance ^{[1] [3] [6]}.

2. Earlier amyloid antibody history and controversy

Aducanumab (Aduhelm®), the first widely publicized anti‑amyloid antibody, was approved in 2021 under an accelerated pathway based on plaque reduction, generating debate over clinical benefit and regulatory standards — a controversy that still shapes public and clinician interpretation of antibody data ^{[7] [8]}. Medical coverage, side‑effect profiles and modest magnitude of cognitive benefit — typically measured in months of slowed decline — are central areas of critique and informed consent emphasized by regulators and clinicians ^{[7] [9]}.

3. Symptomatic treatments: cholinesterase inhibitors and memantine

Donepezil (Aricept®), rivastigmine (Exelon® — including a patch), and galantamine (Razadyne®) are cholinesterase inhibitors approved for symptom management in mild to moderate stages; they boost acetylcholine signalling to temporarily improve cognition or slow symptom progression but do not alter the underlying disease course ^{[2] [4]}. Memantine (Namenda®), an NMDA receptor antagonist approved for moderate to severe Alzheimer’s, regulates glutamate activity and can be combined with cholinesterase inhibitors to help maintain function for some months ^{[10] [4]}.

4. Treatments for behavioral symptoms and adjunct approvals

For agitation associated with Alzheimer’s disease dementia, brexpiprazole (Rexulti®) received supplemental FDA approval to reduce agitation symptoms — an important symptomatic option when non‑drug strategies fail — while clinicians are cautioned to weigh antipsychotic risks in this population ^{[2] [9]}. Guidelines stress using behavioral medications only after non‑pharmacologic approaches and monitoring for side effects ^{[4] [2]}.

5. Limits, risks, and practical considerations

All approved antibody therapies target amyloid and require confirmation of brain amyloid before initiation; benefits are greatest in early disease and are modest in size, and safety concerns — including treatment‑related imaging abnormalities and other adverse events documented in trials — mean patient selection, monitoring, and informed discussion are essential ^{[3] [1] [7]}. Symptomatic drugs can ease daily functioning and behavior but do not halt neurodegeneration; moreover, approvals and labeling typically reflect the disease stages studied, so initiating treatment outside those stages lacks safety/effectiveness data ^{[4] [3]}.

6. How to interpret the current landscape

The treatment landscape now combines modestly disease‑modifying amyloid antibodies for carefully selected early cases with longstanding symptomatic medications and targeted behavioral therapies; the net clinical gain varies by patient, and professional guidance emphasizes individualized decisions based on amyloid testing, stage of disease, comorbidities and risk tolerance ^{[1] [2] [4]}. Reporting from regulators, academic reviews and patient groups underscores hope tempered by limits: these drugs change the calculus of care but are not cures and require infrastructure, monitoring and frank conversations about realistic expectations ^{[1] [8] [7]}.