Ispronicline
Ispronicline is an experimental drug which acts as a partial agonist at neural nicotinic acetylcholine receptors. It progressed to phase II clinical trials for the treatment of dementia and Alzheimer's disease, but is no longer under development.
Ispronicline is subtype-selective, binding primarily to the α4β2 subtype. It has antidepressant, nootropic and neuroprotective effects.
Early stage clinical trials showed that ispronicline was well tolerated, with the main side effects being dizziness and headache. However, mid stage clinical trials failed to show sufficient efficacy to continue development as a pharmaceutical drug.