ATC Group: N05C Hypnotics and sedatives

Amobarbital is a barbiturate derivative with hypnotic and sedative properties (but not antianxiety), used for the induction of sedation during procedures, short-term management of insomnia, and acute management of refractory tonic-clonic seizures.

Brotizolam is a sleep inducing agent. Chemically, it is a triazolo-thienodiazepine. It shortens the time needed to fall asleep, reduces the frequency of awakenings, and prolongs total sleep time.

Clomethiazole has sedative, muscle relaxant and anticonvulsant properties. It is used for hypnosis in elderly and institutionalised patients, for preanaesthetic sedation and especially in the management of withdrawal from ethanol.

Daridorexant is a dual orexin receptor antagonist, acting on both orexin 1 and orexin 2 receptors and equipotent on both. The orexin neuropeptides (orexin A and orexin B) act on orexin receptors to promote wakefulness. Daridorexant antagonises the activation of orexin receptors by the orexin neuropeptides and consequently decreases the wake drive, allowing sleep to occur, without altering the proportion of sleep stages.

Dexmedetomidine is a selective alpha-2 receptor agonist with a broad range of pharmacological properties. It has a sympatholytic effect through decrease of the release of noradrenaline in sympathetic nerve endings. The sedative effects are mediated through decreased firing of locus coeruleus, the predominant noradrenergic nucleus, situated in the brainstem.

Estazolam, a triazolobenzodiazepine derivative, is an oral hypnotic agent. It is indicated for the short-term management of insomnia.

Eszopiclone is indicated for the treatment of insomnia. The mechanism of action of eszopiclone as a hypnotic is unclear; however, its effect could be related to its interaction with GABA-receptor complexes at binding domains located close to or allosterically coupled to benzodiazepine receptors.

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.

Flurazepam is a psychotropic substance from the class of 1,4-benzodiazepines. Flurazepam binds to specific benzodiazepine receptors located on GABA-ergic neurones and potentiates the inhibitory actions of GABA-ergic neurones in the nervous system. Flurazepam is used as a short-term treatment of insomnia.

Benzodiazepines have a widespread action as a result of their enhancing the release of gamma-aminobutyric acid (GABA). They are effective as anti-convulsants, muscle relaxants, anti-anxiety agents, pre-medications and sedative hypnotics. Loprazolam is indicated for the short-term treatment of insomnia including difficulty in falling asleep and/or frequent nocturnal awakenings.

Lormetazepam is a benzodiazepine with anxiolytic, muscle relaxant, sedative and hypnotic properties. Clinical studies have shown minimal effects on REM sleep and on psychomotor performance on the day after treatment with lormetazepam. Lormetazepam is indicated for the short term treatment of insomnia.

Melatonin is a naturally occurring hormone produced by the pineal gland and is structurally related to serotonin. Physiologically, melatonin secretion increases soon after the onset of darkness, peaks at 2-4 am and diminishes during the second half of the night. Melatonin is associated with the control of circadian rhythms and entrainment to the light-dark cycle. It is also associated with a hypnotic effect and increased propensity for sleep.

Meprobamate is a carbamate with hypnotic, sedative and some muscle relaxant properties. It is used for the short-term treatment of anxiety states, muscle tension and associated conditions where anxiety is present. In therapeutic doses its sedative effect rather than a direct action may be responsible for muscle relaxation.

Midazolam is a derivative of the imidazobenzodiazepine group. The free base is a lipophilic substance with low solubility in water. The basic nitrogen in position 2 of the imidazobenzodiazepine ring system enables the active ingredient of midazolam to form water-soluble salts with acids.

Nitrazepam is a benzodiazepine compound with sedative properties. It acts in 30 to 60 minutes to produce sleep lasting 6 to 8 hours.

Phenobarbital is a barbiturate used mainly for its antiepileptic properties. It induces liver enzymes and alters the metabolism of a number of other drugs. Sedation is common but tends to become less of a problem as phenobarbital antiepileptic treatment continues.

Quazepam, like other central nervous system agents of the 1,4-benzodiazepine class, presumably exerts its effects by binding to stereo-specific receptors at several sites within the central nervous system (CNS). The exact mechanism of action is unknown. Quazepam is indicated for the treatment of insomnia.

Ramelteon is a melatonin receptor agonist with both high affinity for melatonin MT₁ and MT₂ receptors and relative selectivity over the MT₃ receptor. The activity of ramelteon at the MT₁ and MT₂receptors is believed to contribute to its sleep-promoting properties, as these receptors, acted upon by endogenous melatonin, are thought to be involved in the maintenance of the circadian rhythm underlying the normal sleep-wake cycle.

Remimazolam is an ultra-short acting benzodiazepine sedative. The effects of remimazolam on the CNS are dependent on the dose administered intravenously and presence or absence of other medicinal products. Remimazolam binds to benzodiazepine sites of gamma amino butyric acid type A [GABA_A] receptors with high affinity, while its carboxylic acid metabolite (CNS7054) has approximately 300 times lower affinity for these receptors.

Scopolamine is a naturally occurring belladonna alkaloid and has anticholinergic properties. It acts as a competitive antagonist to acetylchloline and other parasympathomimetic agents. Its mechanism of action in the central nervous system in preventing motion sickness has yet to be elucidated. Scopolamine produces classical symptoms of parasympathetic blockade.

Secobarbital is a barbituric acid derivative. Secobarbital binds at a distinct binding site associated with a Cl ionopore at the GABA_A receptor, increasing the duration of time for which the Cl ionopore is open.

Tasimelteon is a circadian regulator that resets the master body clock in the suprachiasmatic nucleus (SCN). Tasimelteon acts as a Dual Melatonin Receptor Agonist (DMRA) with selective agonist activity at the MT₁ and MT₂ receptors. These receptors are thought to be involved in the control of circadian rhythms. It is indicated for the treatment of Non-24-Hour Sleep-Wake Disorder (Non-24) in totally blind adults.

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.

Thiopental is a thiobarbiturate with rapid onset for intravenous administration. Thiopental induces hypnosis and anesthesia, but not analgesia.

Triazolam is a short-acting benzodiazepine with anticonvulsant anxiolytic, sedative, muscle relaxant and amnesic properties. It is used as a hypnotic in the short-term management of insomnia.

Triclofos is a melatonin agonist and has hypnotic and sedative actions similar to those of chloral hydrate, but it is more palatable and causes less gastric irritation. It is converted in the body into an active compound which works in the brain to induce sleepiness. It decreases the time taken to fall asleep and increases sleep duration. It is given by mouth in the short-term management of insomnia.

Valerian is used as a hypnotic, anxiolytic and soothing agent since the oils it contains have a similar effect to benzodiazepines. Its mechanism of action, however, remains largely unknown.

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.

Zopiclone is a hypnotic agent belonging to the cyclopyrrolone class of psychotherapeutic agents. It rapidly initiates and sustains sleep without reduction of total REM sleep and with preservation of slow wave sleep. Negligible residual effects are seen the following morning. Its pharmacological properties include hypnotic, sedative, anxiolytic, anticonvulsant and muscle-relaxant actions.