Flurazepam (known under the brand names Dalmane and Dalmadorm) is a drug which is a benzodiazepine derivative. It is a hypnotic agent which does not appear to decrease dream time as measured by rapid eye movements (REM). Furthermore, it decreases sleep latency and number of awakenings for a consequent increase in total sleep time. Flurazepam binds to an allosteric site on GABA-A receptors. Binding potentiates the action of GABA on GABA-A receptors by opening the chloride channel within the receptor, causing chloride influx and hyperpolarization. Flurazepam is useful for the treatment of insomnia characterized by difficulty in falling asleep, frequent nocturnal awakenings, and/or early morning awakening. Flurazepam can be used effectively in patients with recurring insomnia or poor sleeping habits, and in acute or chronic medical situations requiring restful sleep.

Pentobarbital belongs to the class of a short-acting barbiturate is used as sedatives, hypnotics, for the short-term treatment of insomnia, since they appear to lose their effectiveness for sleep induction and sleep maintenance after 2 weeks; preanesthetics and anticonvulsant, in anesthetic doses, in the emergency control of certain acute convulsive episodes, e.g., those associated with status epilepticus, cholera, eclampsia, meningitis, tetanus, and toxic reactions to strychnine or local anesthetics. Pentobarbital binds at a distinct binding site associated with a Cl- ionopore at the GABAA receptor, increasing the duration of time for which the Cl- ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged. All of these effects are associated with marked decreases in GABA-sensitive neuronal calcium conductance (gCa). The net result of barbiturate action is acute potentiation of inhibitory GABAergic tone. Barbiturates also act through potent (if less well characterized) and direct inhibition of excitatory AMPA-type glutamate receptors, resulting in a profound suppression of glutamatergic neurotransmission.

Phenobarbital is a barbiturate derivative used to treat insomnia and anxiety, seizures, hyperbilirubinemia in neonates and cholestasis. Phenobarbital promotes binding to inhibitory gamma-aminobutyric acid subtype receptors, and modulates chloride currents through receptor channels.

Doxylamine is an antihistamine commonly used as a sleep aid. This drug is also used to relieve symptoms of hay fever (allergic rhinitis), hives (rash or itching), and other allergic reactions. Doxylamine is a member of the ethanolamine class of antihistamines and has anti-allergy power far superior to virtually every other antihistamine on the market, with the exception of diphenhydramine (Benadryl). It is also the most powerful over-the-counter sedative available in the United States, and more sedating than many prescription hypnotics. In a study, it was found to be superior to even the barbiturate, phenobarbital for use as a sedative. Doxylamine is also a potent anticholinergic. Like other antihistamines, doxylamine acts by competitively inhibiting histamine at H1 receptors. It also has substantial sedative and anticholinergic effects. Used alone as a short-term sleep aid, in combination with other drugs as a night-time cold and allergy relief drug. Also used in combination with Vitamin B6 (pyridoxine) to prevent morning sickness in pregnant women.

ACT-462206 is a new, potent, and selective dual orexin receptor antagonist that inhibits the stimulating effects of the orexin peptides at both the orexin 1 and 2 receptors. ACT-462206 shows anxiolytic-like properties in rodents without affecting cognition and motor function. It is therefore a potential candidate for the treatment of insomnia and was in phase I of clinical trial, but this research has been discontinued.

Lorediplon is a novel non-benzodiazepine, the hypnotic drug acting as a GABAA receptor modulator, differentially active at the alpha1-subunit, associated with promoting sleep. As compared with other selective benzodiazepine receptor agonists, lorediplon has demonstrated in pre-clinical studies a potent hypnotic profile with potential advantages in sleep maintenance and sleep architecture preservation associated with a good safety profile, that is, no induction of tolerance, lack of next-day hangover effect, weak effect on muscular tone, and weak interaction with ethanol. Lorediplon demonstrated a minimum of 10-fold and the 6-fold increase in potency (respectively) in the spontaneous motor activation studies, compared with the currently marketed hypnotics (zolpidem and zaleplon). Additionally, when the electroencephalogram (EEG) effects of lorediplon and zolpidem were compared in the sleep-wake cycle in the mouse, lorediplon demonstrated a 10-fold increase in potency compared with zolpidem in the sleep-wake cycle and 13% greater possibility of fewer wake episodes than zolpidem. At concentrations of 1.2mg/kg, lorediplon demonstrated a 57%increased effect on Slow Wave Sleep (SWS), when compared with a placebo. In clinical trials, the clinical safety and tolerability were excellent for all doses tested. In pharmacokinetic studies, after oral administration, lorediplon is rapidly absorbed from the gastrointestinal tract reaching maximum plasma concentrations at approximately 2 h. Lorediplon demonstrated a dose-dependent improvement in sleep, whereas zolpidem showed a more sustained wake after sleep onset effect. No next-day hangover effects were observed. These sleep effects are also consistent with the pharmacokinetic profile of lorediplon.

Volinanserin (MDL-100,907) is a highly selective 5-HT2A receptor antagonist. It is widely used in scientific research to investigate the function of the 5-HT2A receptor. Volinanserin is also being trialed as a potential antipsychotic, antidepressant and treatment for insomnia. Volinanserin (M-100907) was in phase III trials for chronic schizophrenia. In August 1999, development was discontinued for acute schizophrenia (schizoaffective disorder) on the basis of poor results. M-100907 is also active in animal models involving blockade of NMDA glutamatergic channel receptors, an effect known to resemble some behavioral symptoms of schizophrenia in man. M-100907 is also claimed in other patents for the treatment of thromboembolic disorders, for the treatment of various developmental neurological disorders such as autism and attention deficit hyperactivity disorder.

Etaqualone (Aolan, Athinazone) is an analog of the hypnotic methaqualone, a non-barbiturate sedative it was developed and marked in France. Etaqualone possesses sedative and hypnotic properties and was used to treat insomnia resulting from its agonist activity at the β subtype of the GABAa receptor.

Fenadiazole is a sedative/hypnotic drug. It has a a unique oxadiazole-based structure. It used to be manufactured by the French pharmaceutical company Laboratoires Jacques Logeais.

Mecloqualone is a quinazoline-class GABAergic and an analog of methaqualone. It acts as an agonist of the beta subtype of GABAa receptor and induces sedative, hypnotic and anxiolytic effects. Mecloqualone was marketed (mostly in france) under the names Nubrene and Casfen for the treatment of insomnia. Mecloqualone is no longer prescribed because of concerns about its potential for abuse and overdose. In the United States, it is registered as a Schedule-I non-narcotic controlled substance.