The accurate explanation
Her daughter asks why donepezil has not kept her mother's memory from getting worse. Donepezil is a cholinesterase inhibitor: it increases the acetylcholine available at remaining synapses and gives a modest symptomatic benefit, but it does not stop the loss of neurons, so the disease continues to progress. The accurate explanation is that it raises brain acetylcholine but does not stop neuron loss.
How donepezil works
In Alzheimer disease, cholinergic neurons that support memory and attention are lost early. Acetylcholine released by the remaining neurons is normally broken down quickly by acetylcholinesterase. Donepezil inhibits this enzyme, so acetylcholine lasts longer at the synapse and transmission improves. This can stabilize or modestly improve memory, attention, and daily function for a period, but it does not address the underlying neurodegeneration. As more neurons are lost, there are fewer cholinergic synapses for the drug to support, and symptoms worsen despite treatment.
| Drug or class | Mechanism | Use |
|---|
| Donepezil | Cholinesterase inhibitor; raises acetylcholine | Symptomatic, mild to severe Alzheimer disease |
| Memantine | Blocks the NMDA glutamate receptor | Moderate to severe Alzheimer disease |
| Anti-amyloid antibodies | Clear amyloid plaques | Early Alzheimer disease |
| Levodopa | Replaces dopamine | Parkinson disease |
Why the other explanations are wrong
Clearing amyloid plaques describes anti-amyloid monoclonal antibodies such as lecanemab and donanemab, not donepezil. Blocking glutamate describes memantine, which blocks the N-methyl-D-aspartate (NMDA) receptor and is used in moderate to severe disease. Replacing dopamine lost from the basal ganglia describes levodopa for Parkinson disease and is not a treatment for Alzheimer disease.
Talking with the family
The nurse explains that the medicine may help symptoms for a time but cannot halt the disease, so gradual decline is expected and does not mean the drug has failed or that a dose was missed. The nurse encourages the family to continue the medicine as prescribed, report side effects such as nausea, diarrhea, slow pulse, or fainting, and use supportive strategies and community resources.
Exam takeaway
Key point Cholinesterase inhibitors give symptomatic benefit only; they do not stop neurodegeneration. Match each mechanism to its drug: memantine blocks glutamate, anti-amyloid antibodies clear plaques.