Aprobarbital is a barbiturate derivative. Aprobarbital have been used for the short-term treatment of insomnia and for routine sedation to relieve anxiety, tension, and apprehension however, barbiturates generally have been replaced by benzodiazepines.

Melatonin (5-methoxy N-acetyltryptamine) is a hormone synthesized and released from the pineal gland at night, which acts on specific high affinity G-protein coupled receptors to regulate various aspects of physiology and behaviour, including circadian and seasonal responses, and some retinal, cardiovascular and immunological functions. Melatonin is also made synthetically and available without a prescription as an over-the-counter (OTC) dietary supplement in the U.S. Melatonin supplementation has many uses, however, it has been widely studied for treatment of jet lag and sleep disorders. Parents may consider using melatonin to help their child who has a trouble falling asleep. A medical professional should always evaluate insomnia or other sleeping disorders in children. Additionally, melatonin has been shown to protect against oxidative stress in various, highly divergent experimental systems. There are many reasons for its remarkable protective potential. In mammals, melatonin binds to a number of receptor subtypes including high-affinity (MT1 and MT2) and low-affinity (MT3, nuclear orphan receptors) binding sites, which are distributed throughout the central nervous system and periphery.

Barbital, the one of the series of barbiturates, has hypnotic, sedative, and anticonvulsant properties and used under the trade name Veronal. It calmed manic patients and helped melancholic patients to sleep and was an effective inducer of sleep in insomniacs, but at the same time compound could induced dependence. It was substituted by the butyl analog, butobarbital, which was three times stronger and its period of action was much shorter due to its lipophilicity. Barbital is a ligand of GABA-receptor complex and in addition, it could have another target, a creatine kinase.

Domitor (medetomidine hydrochloride) is indicated for use in dogs: for restraint, sedation and analgesia associated with clinical examinations and procedures, minor surgery, pre-anaesthesia and as a premedicant before thiopentone-halothane general a naesthesiaand as a premedicant before general anaesthesia with propofol. In combination with butorphanol for sedation and analgesia, and as a premedicant prior to thiopentone anaesthesia. In cats: for restraint and sedation. Medetomidine is a potent and highly selective alpha2-adrenoreceptor agonist with both central and peripheral activity, and acting both presynaptically and postsynaptically. Its primary effects are sedative and analgesic resulting from its central depressant activity. It has no local anaesthetic properties. Like other compounds of its class there are secondary effects, including bradycardia. Blood pressure is increased but then returns to normal or just below. Body temperature is decreased in a dose dependent manner and intestinal motility is also reduced. The drug has been developed by Orion Pharma. It is currently approved for dogs in the United States, and distributed in the United States by Pfizer Animal Health and by Novartis Animal Health in Canada under the product name Domitor. The marketed product is a racemic mixture of two stereoisomers; dexmedetomidine is the isomer with more useful effects, and is now marketed as Dexdomitor.

Metomidate is a non-barbiturate imidazole which produces a sleepy condition of 20-60 minutes duration without substantial analgesia. Since the beginning of 1997 the use of the hypnotic drug metomidate (Hypnodil) in swine is nor longer allowed. This ban caused a substantial therapeutic deficit for anesthesia in swine. 11C-metomidate may be used with positron emission tomography which can differentiate adrenocortical from nonadrenocortical tumors and a suspected adrenocortical cancer may be characterized and staged before surgery. Metomidate hydrochloride is for the sedation and anesthesia of aquarium and non-food fish species. Aquacalm has been granted Indexed status by the FDA for this purpose.

Xylazine was developed as an antihypertensive agent. During clinical studies in people xylazine was found to have excessive central nervous system depressant effects and it was subsequently introduced for veterinary use as a sedative, analgesic and relaxant. Xylazine is a potent alpha-2 adrenergic agonist. Xylazine in horses and Cervidae may occasionally cause slight muscle tremors, bradycardia with partial A-V heart block and a reduced respiratory rate. Movement in response to sharp auditory stimuli may be observed.

Romifidine is an alpha2-adrenergic agonist, which as a sedative and analgesic in horses. The drug was approved by FDA under the name Sedivet. It has no use in humans.

Detomodine hydrochloride is a sedative with analgesic properties and α2-adrenergic agonist The dose-dependent sedative and analgesic effects reduce production of excitatory neurotransmitters, thereby calming the horse, relieving abdominal pain, and facilitating bronchoscopy and other procedures. Currently, detomidine is only licensed for use in horses.

Cinolazepam is a drug which is a benzodiazepine derivative. It possesses anxiolytic, anticonvulsant, sedative and skeletal muscle relaxant properties. Cinolazepam is not approved for sale in the United States or Canada. Cinolazepam binds to central benzodiazepine receptors, which interact allosterically with GABA receptors. This potentiates the effects of the inhibitory neurotransmitter GABA, increasing the inhibition of the ascending reticular activating system and blocking the cortical and limbic arousal that occurs following stimulation of the reticular pathways. Statistical analyses of objective sleep variables in men demonstrated a significant improvement of sleep maintenance after cinolazepam as reflected by an increase of sleep efficiency, decrease of wake time (during total sleep period) and number of awakenings as compared with the placebo. It is indicated for the treatment of sleep disorders of different etiologies.

Zopiclone (brand names Zimovane and Imovane) is a nonbenzodiazepine hypnotic agent used in the treatment of insomnia. The therapeutic pharmacological properties of zopiclone include hypnotic, anxiolytic, anticonvulsant, and myorelaxant properties. Zopiclone and benzodiazepines bind to different sites on GABAA-containing receptors, causing an enhancement of the actions of GABA to produce the therapeutic and adverse effects of zopiclone. The metabolite of zopiclone called desmethylzopiclone is also pharmacologically active, although it has predominately anxiolytic properties. One study found some slight selectivity for zopiclone on α1 and α5 subunits, although it is regarded as being unselective in its binding to α1, α2, α3, and α5 GABAA benzodiazepine receptor complexes. Desmethylzopiclone has been found to have partial agonist properties, unlike the parent drug zopiclone, which is a full agonist. The mechanism of action of zopiclone is similar to benzodiazepines, with similar effects on locomotor activity and on dopamine and serotonin turnover. A meta-analysis of randomised controlled clinical trials that compared benzodiazepines to zopiclone or other Z drugs such as zolpidem and zaleplon has found few clear and consistent differences between zopiclone and the benzodiazepines in sleep onset latency, total sleep duration, number of awakenings, quality of sleep, adverse events, tolerance, rebound insomnia, and daytime alertness. After oral administration, zopiclone is rapidly absorbed, with a bioavailability around 75–80%. Time to peak plasma concentration is 1–2 hours. High-fat meal preceding zopiclone administration does not change absorption (as measured by AUC), but reduces peak plasma levels and delays its occurrence, thus may delay the onset of therapeutic effects. The pharmacokinetics of zopiclone in humans are stereoselective. After oral administration of the racemic mixture, Cmax (time to maximum plasma concentration), area under the plasma time-concentration curve (AUC) and terminal elimination half-life values are higher for the dextrorotatory enantiomers, owing to the slower total clearance and smaller volume of distribution (corrected by the bioavailability), compared with the levorotatory enantiomer. In urine, the concentrations of the dextrorotatory enantiomers of the N-dimethyl and N-oxide metabolites are higher than those of the respective antipodes. Zopiclone is sometimes used as a method of suicide. It has a similar fatality index to that of benzodiazepine drugs, apart from temazepam, which is particularly toxic in overdose.