Antihistamines memory

The use of antihistamines can be traced back to the beginning of 1940s. The applications of the first-generation antihistamines were limited since they cause significant adverse effects such as sedation, memory impairment and psychomotor dysfunction. The second-generation antihistamines have significantly fewer central nervous system (CNS) adverse effects because they penetrate the blood-brain barrier much less extensively. 

Patat A, Perault MC, Vandel B, Ulliac N, Zieleniuk I, Rosenzweig P. Lack of interaction between a new antihistamine, mizolastine, and lorazepam on psychomotor performance and memory in healthy volunteers. Br J Clin Pharmacol 1995 39(l) 31-8. 

Acetylcholine is a neurohormone that enhances peristalsis, wakefulness, and memory and is essential for nerve transmission. A deficiency of brain cell receptors that bind acetylcholine—cholinergic receptors—contributes to the characteristic loss of memory in Alzheimer s disease. Cholinergic receptors are structurally similar to those that bind histamine. Therefore, antihistamines and cholinergic agents show overlapping activities. As a result, the antihistamine diphenhydramine has been used to treat insomnia and to combat motion sickness. 

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