Physostigmine (Phy) is one of the oldest drug isolated from Calabar beans and successfully used for the treatment of glaucoma in 1864. Since then, it has been widely employed for various therapeutic purposes. Recently, it has gained prominence because of its clinical trials in the treatment of Alzheimer's disease. Physostigmine was used to treat glaucoma. It can be applied topically to the conjunctiva. Phy is also considered to be a potent prophylactic antidote for organophosphate poisoning. It is a reversible cholinesterase (ChE) inhibitor and has a short duration of action. For the last 50 years, numerous authors have shown that pretreatment with Phy would rapidly improve the incapacitating effects of organophosphate intoxication in various animal species. Phy carbamylates to a portion of ChE enzyme and thus protects the enzyme from binding with organophosphate, which are irreversible ChE inhibitors. The carbamylated ChE enzyme decarbamylates to free the enzyme for normal functioning. The rates of decarbamylation of butyrylcholinesterase (BuChE) in plasma and ChE in brain and muscle are different and are related to the half-life of Phy in these tissues. In addition to ChE inhibition, Phy has a direct action on acetylcholine (ACh) receptor ionophore complex by interacting with the ACh-gated cation channels. A cholinesterase inhibitor that is rapidly absorbed through membranes. It also can cross the blood-brain barrier and is used when central nervous system effects are desired, as in the treatment of severe anticholinergic toxicity.

Morpholine salicylate is a derivative of salicylic acid. It is a non-steroidal anti-inflammatory drug and was marketed under a tradename Retarcyl, Dolical and Deposal.

Dimebon (latrepirdine) is an orally available, small molecule, gamma carboline derivative that was developed and used in Russia as an over-the-counter oral antihistamine for allergy treatment since 1980s. In 1990s it was shown that Dimebon has promising potential in treating neurodegenerative diseases. In 2003, Medivation Inc acquired the rights to Dimebon. Medivation went public in December 2004, with Dimebon as the only drug in its pipeline. The product was being developed by Medivation and Pfizer as a treatment for early-stage Alzheimer's disease and Huntington's disease. However, development was discontinued by Medivation and Pfizer in early 2012. Dimebon inhibits alpha-Adrenergic receptors (alpha1A, alpha1B, alpha1D, and alpha2A), Histamine H1 and H2 receptors and Serotonin 5-HT2c, 5-HT5A, 5-HT6 receptors with high affinity. Dimebon may act by blocking NMDA receptors or voltage-gated Ca2+ channels and by preventing mitochondrial permeability pore transition.