Meprobamate is a carbamate derivative used as an anxiolytic drug. Meprobamate enhances GABA-A currents, and at higher concentration, exhibits a separate channel-blocking effect that limits the magnitude of GABA(A) receptor potentiation. It is also a potent adenosine reuptake inhibitor (AdoRI), which is most likely responsible for its lesser degree of sedation compared to barbiturates. Meprobamate was withdrawn from European and Canadian markets due to its potential to cause physical and psychological dependence.

Delorazepam is a benzodiazepine with anxiolytic effects. It is a metabolite of the designer drug diclazepam that can be detected in either the serum or urine. Delorazepam can also be produced by enzymatic treatment of lorazepam with β-glucuronidase. It is indicated for the treatment of anxiety, tension and other somatic or psychiatric manifestations associated with anxiety syndrome, insomnia. The side effects and precautions for use of delorazepam are the same as for all benzodiazepines, in particular as regards the development of dependence (mental and physical) and tolerance. Prolonged use may lead to difficulties remembering recent names and events (anterograde amnesia). It has been approved for marketing in Italy.

Halazepam is a benzodiazepine derivative. It possesses anxiolytic, anticonvulsant, sedative and skeletal muscle relaxant properties. Halazepam is used to relieve anxiety, nervousness, and tension associated with anxiety disorders. Halazepam (Paxipam) is no longer commercially available in the United States. Common adverse effects are: hypotension, nausea, xerostomia, confusion, headache. Alcohol should be avoided while taking Paxipam as it causes drowsiness as well. Medications that also cause drowsiness should not be taken along with Paxipam. These include: Antidepressants, Pain relievers, Seizure medications, Muscle relaxants, Antihistamines, Sleeping pills and sedatives.

Prazepam is a benzodiazepine derivative and is indicated to treat symptoms of anxiety. Benzodiazepines are used to treat severe incapacitating symptoms or symptoms leading to an extreme suffering for the patient. Prazepam is believed to stimulate GABA receptors in the ascending reticular activating system. Since GABA is inhibitory, receptor stimulation increases inhibition and blocks both cortical and limbic arousal following stimulation of the brain stem reticular formation. Prazepam is a prodrug for N-desmethyl-diazepam, which is responsible for the therapeutic effects of prazepam. Prazepam was discontinued in USA.

CHLORAL BETAINE, a chemical complex of chloral hydrate and betaine, is a nonbarbiturate sedative and hypnotic. It is indicated for sleep induction, preoperative sedation, and daytime sedation. CHLORAL BETAINE is converted to chloral hydrate in the body and its action on the central nervous system is identical with that of chloral hydrate.

Mebutamate (Capla, Dormate) is a biscarbamate drug that has anxiolytic, sedative, and antihypertensive effects. It is marketed under many trade names, including Capla and Dormate. Its preparation was reported in a 1959 US patent to Carter Products. It is less well known that mebutamate is also hypnotic. In a 1967 study, L. Tetreault, P. Richer, and J. M. Bordeleau in Montreal found that, at a dose of 600 mg, mebutamate has hypnotic properties that “affect the duration and quality of sleep induction, and the duration and quality of sleep, without disturbing the state of the subject upon awakening and during the morning.” A higher dose (900 mg) did not change the overall effect, which was “consistently between that of secobarbital at 200 mg and 100 mg.” The authors did not observe any significant side effects. Mebutamate is one of many GABAergic drugs which act via allosteric agonism of the GABAA receptor at the β-subreceptor similar to barbiturates. In contrast, benzodiazepines act at the α-subreceptor. As such, carbamates and barbiturates, possess analgesic properties which the benzodiazepine class of drugs does not.

Petrichloral is the tetrahemiacetal pentaerythritol derivative of chloral. Animal trials and studies among institutionalized patients offer clinical evidence as to the therapeutic relationship between the drugs. Petrichloral exhibits a hypnotic and sedative action similar to chloral hydrate. It is better tolerated than the later drug.

Ethinamate was used to treat insomnia (trouble in sleeping) under the brand name VALMID, but then was replaced by other more efficacy medicines. The mechanism of action was not known. However, was studies, which showed that ethinamate inhibits carbonic anhydrases I and did not inhibit II. Nevertheless, even inhibition carbonic anhydrases I is not sufficiently strong to implicate carbonic anhydrases I in the mechanism of action.

Ethchlorvynol is used to treat insomnia (trouble in sleeping). It developed by Pfizer in the 1950s. In the United States it was sold by Abbott Laboratories under the tradename Placidyl. Although the exact mechanism of action is unknown, ethchlorvynol appears to depress the central nervous system in a manner similar to that of barbiturates – by means of GABA-A receptors modulation. Moderate side effects are: Skin rash or hives; dizziness or faintness; unusual excitement, nervousness, or restlessness. It is addictive and after prolonged use can cause withdrawal symptoms including convulsions, hallucinations, and memory loss.

Mephobarbital us a barbiturate derivative used primary as an anticonvulsant, but also as a sedative and anxiolytic. Marketing of mephobarbital was discontinued in 2012.