The story
From riva- (of known origin) + -stigmine (“acetylcholinesterase inhibitor”).
Etymology from Wiktionary, CC BY-SA 4.0.
rivastigmine
Today it means: A drug C₁₄H₂₂N₂O₂ that increases acetylcholine levels by inhibiting the action of cholinesterase and is used to treat dementia associated with Alzheimer's disease and Parkinson's disease. Full definition →