Reversible acetylcholinesterase inhibitor / NMDA receptor antagonist (natural alkaloid supplement)
Inhibits acetylcholinesterase to increase acetylcholine levels; also exhibits neuroprotective and NMDA receptor antagonism properties
None (supplement, not FDA-approved)
Cognitive enhancement, Alzheimer’s disease (AD), vascular dementia, mild cognitive impairment (MCI)
Oral capsules/tablets, typically OTC supplements
100–400 mcg/day divided BID; dosing varies by product
100–400 mcg/day
Limited formal pharmacokinetic data; oral absorption variable
Nausea, diarrhea, insomnia, bradycardia, dizziness
Unknown; long-term safety data lacking
Monitor for bradycardia and additive cholinergic effects, especially if combined with other cholinergic drugs
None
May offer modest cognitive benefit in AD, vascular dementia, and post-stroke cognitive decline. Limited evidence supports use in younger adults with attention or memory complaints. Use caution in patients with cardiac conduction abnormalities or when combined with other cholinergic agents due to potential additive effects. Not FDA-approved and lacks long-term safety data; use should be individualized with informed consent.