ICD-10 Specific code F51.0: Nonorganic insomnia

Clorazepate is a benzodiazepine with anxiolytic, sedative, hypnotic, and anticonvulsant properties. Clorazepate exerts its effect by de-activating the nervous system through potentiation of the inhibitory effect of gamma-aminobutyric acid (GABA) on the GABA-A receptors by binding to a site that is distinct from the GABA binding site.

Flunitrazepam is a member of the benzodiazepine group of drugs and is closely related to nitrazepam, flurazepam and clonazepam. It has marked sedative and hypnotic properties with a rapid onset of action and is used in severe cases of insomnia.

Temazepam is a benzodiazepine with hypnotic and sedative effects as well as anxiolytic activity. Temazepam effects are likely to be due to potentiation of gamma-aminobutyric acid (GABA), although other neurotransmitters may also be affected.

Tiapride is an atypical neuroleptic which exhibits selectivity in in-vitro studies for D₂ and D₃ dopamine subtype receptors without any affinity for subtype receptors of the principal central neurotransmitters (including serotonin, noradrenaline and histamine).

Zaleplon is a pyrazolopyrimidine hypnotic that is structurally different from benzodiazepines and other hypnotics. Zaleplon binds selectively to the benzodiazepine type I receptor.

Zolpidem is an imidazopyridine which preferentially binds the omega-1 receptor subtype (also known as the benzodiazepine-1 subtype) which corresponds to GABA-A receptors containing the alpha-1 sub-unit, whereas benzodiazepines non-selectively bind both omega-1 and omega-2 subtypes. The modulation of the chloride anion channel via this receptor leads to the specific sedative effects demonstrated by zolpidem. These effects are reversed by the benzodiazepine antagonist flumazenil.