Glutethimide is a GABA agonist that was introduced by Ciba in 1954 as a safe alternative to barbiturates to treat insomnia. Before long, however, it had become clear that glutethimide was just as likely to cause addiction and caused similarly severe withdrawal symptoms. Glutethimide was discontinued in the US by manufacturers in 1993. Current production levels in the United States point to it only being used in small-scale research.

Methyprylon (brand name Noludar) is a sedative agent, which used to treat insomnia. But then the drug was replaced in the market by another drugs with less side effects. The precise mechanism of action is not known, but was made suggestion, that methyprylon increases the effects of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter in the brain.

Methyprylon (brand name Noludar) is a sedative agent, which used to treat insomnia. But then the drug was replaced in the market by another drugs with less side effects. The precise mechanism of action is not known, but was made suggestion, that methyprylon increases the effects of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter in the brain.

Thiamylal is a barbiturate that is administered intravenously for the production of complete anesthesia of short duration, for the induction of general anesthesia, or for inducing a hypnotic state. Thiamylal, a barbiturate, is used in combination with acetaminophen or aspirin and caffeine for its sedative and relaxant effects in the treatment of tension headaches, migraines, and pain. Barbiturates act as nonselective depressants of the central nervous system (CNS), capable of producing all levels of CNS mood alteration from excitation to mild sedation, hypnosis, and deep coma. In sufficiently high therapeutic doses, barbiturates induce anesthesia. Thiamylal 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.

Pregnenolone sulfate is an endogenous neurosteroid with excitatory effects in the brain, acting as a potent negative allosteric modulator of the GABAA receptor, a positive allosteric modulator of the NMDA receptor, and activator of transient receptor potential cation channel TRPM1 and TRPM3. In the model of schizophrenia, treatment with pregnenolone sulfate normalized the hyperlocomotion and stereotypic bouts, and rescued the PPI deficits of dopamine transporter knockout mice. Promnesic properties of pregnenolone sulfate were demonstrated in rat models of spatial memory performance.

Pregnenolone sulfate is an endogenous neurosteroid with excitatory effects in the brain, acting as a potent negative allosteric modulator of the GABAA receptor, a positive allosteric modulator of the NMDA receptor, and activator of transient receptor potential cation channel TRPM1 and TRPM3. In the model of schizophrenia, treatment with pregnenolone sulfate normalized the hyperlocomotion and stereotypic bouts, and rescued the PPI deficits of dopamine transporter knockout mice. Promnesic properties of pregnenolone sulfate were demonstrated in rat models of spatial memory performance.

Barbiturates are non-selective depressants of the central nervous system. Butabarbital is one of them, which is used under brand name butisol sodium as a sedative or hypnotic. Like other barbiturates, butabarbital is capable of producing all levels of CNS mood alteration from excitation to mild sedation, to hypnosis, and deep coma. The mechanism of action by which barbiturates exert their effect is not yet completely understood, but is assumed, that butabarbital 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.

Sodium thiopental (also known as Sodium Pentothal, thiopental) was discovered in 1930s by investigators working for Abbott Laboratories. Thiopental sodium was used for the induction of general anesthesia and is used as an adjunct to provide hypnosis during balanced anesthesia with other anesthetic agents, including analgesics and muscle relaxants. Thiopental sodium was also used as an adjunct for control of convulsive disorders of various etiology, including those caused by local anesthetics. Finally, thiopental sodium had been used to reduce the intracranial pressure in patients with increased intracranial pressure, if controlled ventilation is provided. Nevertheless, these prescriptions of drug were discontinued. In addition, this drug was banned for use in US executions. Thiopental sodium acts through the CNS with particular activity in the mesencephalic reticular activating system. It was shown, that mechanism of action of sodium thiopental via GABAA receptor. Thiopental 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.

Secobarbital sodium, a barbiturate, is FDA approved for the treatment of insomnia and for pre-anesthetic use. This drug binds at a distinct 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. Adverse reactions are drowsiness, lethargy, hangover, paradoxical excitement in elderly patients, somnolence. Rifampin may decrease secobarbital levels by increasing metabolism.

Butethal is a sedative and a hypnotic drug indicated for the treatment of severe intractable insomnia. It acts on receptors in the brain (GABA A receptors) causing the release of the chemical GABA. This chemical inhibits certain areas of the brain resulting in sleepiness. Common side effects are: drowsiness, sedation, unsteadiness, vertigo and inco- ordination. Also, hangover effect, paradoxical excitement, confusion, memory defects and skin rashes. Interactions may occur with the following: adrenocorticoids (cortisone-like medicine), anticoagulants (blood thinners), carbamazepine, corticotropin (barbiturates may decrease the effects of these medicines), central nervous system (CNS) depressants (using these medicines with barbiturates may result in increased CNS depressant effects), divalproex sodium, valproic acid (using these medicines with barbiturates may change the amount of either medicine that you need to take), and oral contraceptives containing estrogens (barbiturates may decrease the effectiveness of these oral contraceptives, and you may need to change to a different type of birth control).