[1][2] It has been used in the treatment of sleep disturbances since the early 1970s in several European countries including France, Italy, and Luxembourg.

[3][4] It is commonly used with children and adolescents on account of its favorable safety and tolerability profile and lack of abuse potential.

[5][6][7][8][9][10] Originally believed to act as an antihistamine and anticholinergic,[11] niaprazine was later discovered to have low or no binding affinity for the H1 and mACh receptors (Ki = > 1 μM), and was instead found to act as a potent and selective 5-HT2A and α1-adrenergic receptor antagonist (Ki = 75 nM and 86 nM, respectively).

[12] However, from animal studies it is known that pFPP, unlike niaprazine, does not produce sedative effects, and instead exerts a behavioral profile indicative of serotonergic activation.

Reaction with hydroxylamine produces the oxime, (5), which is reduced with lithium aluminium hydride to give the amine (6).