Niaprazine (

INN Inns are generally establishments or buildings where travelers can seek lodging, and usually, food and drink. Inns are typically located in the country or along a highway; before the advent of motorized transportation they also provided accommo ...

) (brand name Nopron) is a

sedative A sedative or tranquilliser is a substance that induces sedation by reducing irritability or excitement. They are CNS depressants and interact with brain activity causing its deceleration. Various kinds of sedatives can be distinguished, but t ...

hypnotic Hypnotic (from Greek ''Hypnos'', sleep), or soporific drugs, commonly known as sleeping pills, are a class of (and umbrella term for) psychoactive drugs whose primary function is to induce sleep (or surgical anesthesiaWhen used in anesthesia ...

drug A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via insuffla ...

of the phenylpiperazine group. It has been used in the treatment of sleep disturbances since the early 1970s in several European countries including France, Italy, and Luxembourg. It is commonly used with children and adolescents on account of its favorable safety and

tolerability Tolerability refers to the degree to which overt adverse effects of a drug can be tolerated by a patient. Tolerability of a particular drug can be discussed in a general sense, or it can be a quantifiable measurement as part of a clinical study. U ...

profile and lack of

abuse potential Substance abuse, also known as drug abuse, is the use of a drug in amounts or by methods which are harmful to the individual or others. It is a form of substance-related disorder. Differing definitions of drug abuse are used in public health, ...

. Originally believed to act as an antihistamine and anticholinergic, niaprazine was later discovered to have low or no binding

affinity Affinity may refer to: Commerce, finance and law * Affinity (law), kinship by marriage * Affinity analysis, a market research and business management technique * Affinity Credit Union, a Saskatchewan-based credit union * Affinity Equity Partn ...

for the H₁ and mACh receptors (K_i = > 1 μM), and was instead found to act as a potent and selective 5-HT_2A and α₁-adrenergic receptor

antagonist An antagonist is a character in a story who is presented as the chief foe of the protagonist. Etymology The English word antagonist comes from the Greek ἀνταγωνιστής – ''antagonistēs'', "opponent, competitor, villain, enemy, riv ...

(K_i = 75 nM and 86 nM, respectively). It possesses low or no affinity for the 5-HT_1A, 5-HT_2B, D₂, and

β-adrenergic The adrenergic receptors or adrenoceptors are a class of G protein-coupled receptors that are targets of many catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) produced by the body, but also many medications like beta ...

, as well as at SERT and

VMAT The vesicular monoamine transporter (VMAT) is a transport protein integrated into the membranes of synaptic vesicles of presynaptic neurons. It transports monoamine neurotransmitters – such as dopamine, serotonin, norepinephrine, epinephri ...

(K_i = all > 1 μM), but it does have some affinity for the α₂-adrenergic receptor (K_i = 730 nM). Niaprazine has been shown to

metabolize Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...

to the compound ''para''-fluorophenylpiperazine (''p''FPP) in a similar manner to how trazodone and nefazodone metabolize to ''meta''-chlorophenylpiperazine (''m''CPP). It is unclear what role, if any, ''p''FPP plays in the clinical effects of niaprazine. However, from animal studies it is known that ''p''FPP, unlike niaprazine, does not produce sedative effects, and instead exerts a behavioral profile indicative of serotonergic activation.

References

{{Piperazines Alpha-1 blockers Alpha-2 blockers Fluoroarenes Hypnotics Nicotinamides Phenylpiperazines Sedatives