Does donepezil (Aricept) have a sedative or stimulating effect on the central nervous system?

Donepezil is a selective acetylcholinesterase inhibitor. Its main mechanism of action is to inhibit the decomposition of acetylcholine in the synaptic cleft, thereby increasing the concentration of acetylcholine in the central nervous system and improving signal transmission between neurons. Because acetylcholine plays an important role in cognition, learning and memory functions, donepezil is mainly used to treat cognitive disorders such as Alzheimer's disease. From a pharmacological perspective, it does not directly act as a "sedative" or "stimulant", but rather enhances the cognitive activity of the brain by improving neurotransmitter function.

In terms of clinical manifestations, donepezil is not a sedative drug. On the contrary, it can improve the patient's cognitive clarity and attention to a certain extent. Some patients will feel more alert and have improved thinking agility after taking it. This effect can be understood as a "central nervous system excitement trend". However, this stimulant effect is not obviously strong like caffeine or central stimulants, but is achieved by restoring the function of cholinergic neurons.

On the other hand, donepezil may also cause reactions in some patients that are contrary to“excitement”. For example, some patients may experience fatigue, dizziness or even insomnia, which is related to the impact of elevated central acetylcholine levels on the sleep regulatory mechanism. Especially when the drug is taken at night, side effects such as decreased sleep quality or vivid dreams are more likely to occur, showing some kind of "increased arousal" effect. Therefore, clinically, doctors sometimes recommend that patients take medications in the morning, based on tolerance, to reduce the risk of sleep disorders.

To sum up, the effect of donepezil on the central nervous system is neither "sedative" nor simply "exciting" in the traditional sense. Its main function is to improve cognitive function, promoting nerve signaling by increasing acetylcholine levels, which may manifest as enhanced attention and memory in some patients, while in others it may cause insomnia or restlessness due to overstimulation. Therefore, it would be more accurately described as a "cognitive function enhancing drug" rather than a simple central nervous system depressant or stimulant.

Reference link:https://www.drugs.com