Nonbenzodiazepines (), sometimes referred to colloquially as Z-drugs (as many of their names begin with the letter "z"), are a class of

psychoactive A psychoactive drug, psychopharmaceutical, psychoactive agent or psychotropic drug is a chemical substance, that changes functions of the nervous system, and results in alterations in perception, mood, consciousness, cognition or behavior. Th ...

drugs that are very benzodiazepine-like in nature. They are used in the treatment of sleep problems, and for their

anxiolytic An anxiolytic (; also antipanic or antianxiety agent) is a medication or other intervention that reduces anxiety. This effect is in contrast to anxiogenic agents which increase anxiety. Anxiolytic medications are used for the treatment of anxiet ...

effects. Nonbenzodiazepine

pharmacodynamics Pharmacodynamics (PD) is the study of the biochemical and physiologic effects of drugs (especially pharmaceutical drugs). The effects can include those manifested within animals (including humans), microorganisms, or combinations of organisms ...

are almost entirely the same as

benzodiazepine Benzodiazepines (BZD, BDZ, BZs), sometimes called "benzos", are a class of depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, ...

drugs and therefore exhibit similar benefits, side-effects, and risks. However, nonbenzodiazepines have dissimilar or entirely different chemical structures and are therefore unrelated to benzodiazepines on a molecular level.

Classes

Currently, the major chemical classes of nonbenzodiazepines are: Imidazopyridines *

Alpidem Alpidem (Ananxyl) is an anxiolytic drug from the imidazopyridine family, related to the more well known sleeping medication zolpidem. Unlike zolpidem however, alpidem does not produce sedative effects at normal doses, and is instead used specific ...

* Necopidem *

Saripidem Saripidem is a sedative and anxiolytic drug in the imidazopyridine family, which is related to the better known drugs zolpidem and alpidem. Saripidem has a similar pharmacological profile to the benzodiazepine family of drugs including sedative ...

Zolpidem Zolpidem, sold under the brand name Ambien, among others, is a medication primarily used for the short-term treatment of sleeping problems. Guidelines recommend that it be used only after cognitive behavioral therapy for insomnia and behavior ...

(Ambien, Ambien CR, Intermezzo, Zolpimist, Edluar, Ivadal, Sanval, Stilnox, etc.)

Pyrazolopyrimidine Pyrazolopyrimidines are a series of isomeric heterocyclic chemical compounds with the molecular formula C6H5N3. They form the central core of a variety of more complex chemical compounds including some pharmaceuticals and pesticides. Pharmace ...

s *

Divaplon Divaplon (RU-32698) is a nonbenzodiazepine, anxiolytic and anticonvulsant drug from the pyrazolopyrimidine family of drugs. It acts as a partial agonist In pharmacology, partial agonists are drugs that bind to and activate a given receptor, but ...

* Fasiplon * Indiplon * Lorediplon * Ocinaplon *

Panadiplon Panadiplon (U-78875) is an anxiolytic drug with a novel chemical structure that is not closely related to other drugs of this type. It has a similar pharmacological profile to the benzodiazepine family of drugs, but with mainly anxiolytic propert ...

Taniplon Taniplon is a nonbenzodiazepine anxiolytic drug from the imidazoquinazoline family of drugs. Taniplon binds strongly to benzodiazepine sites on the GABAA receptor and has similar anxiolytic effects in animals, but with less sedative or muscle r ...

Zaleplon Zaleplon, sold under the brand names Sonata among others, is a sedative- hypnotic, used to treat insomnia. It is a nonbenzodiazepine hypnotic from the pyrazolopyrimidine class. It is manufactured by King Pharmaceuticals and Gedeon Richte ...

(Sonata, Starnoc, Andante) Cyclopyrrolones *

Eszopiclone Eszopiclone, sold under the brand-name Lunesta among others such as Night Calm in Egypt, is a medication used in the treatment of insomnia. Evidence supports slight to moderate benefit up to six months. It is taken orally. Common side effects i ...

(Lunesta, Valnoc, etc.) * Pagoclone * Pazinaclone * Suproclone * Suriclone *

Zopiclone Zopiclone, sold under the brand name Imovane among others, is a nonbenzodiazepine used to treat difficulty sleeping. Zopiclone is molecularly distinct from benzodiazepine drugs and is classed as a cyclopyrrolone. However, zopiclone increases th ...

(Imovane, Zimovane, Somnol, etc.) β-Carbolines * Abecarnil * Gedocarnil *

SL-651,498 SL651498 is an anxiolytic and anticonvulsant drug used in scientific research, with a chemical structure most closely related to β-carboline derivatives such as abecarnil and gedocarnil. It has similar effects to benzodiazepine drugs, but is str ...

* ZK-93423 Others * CGS-20625 * CGS-9896 * CL-218,872 * ELB-139 * GBLD-345 * HIE-124 *

L-838,417 L-838,417 is an anxiolytic drug used in scientific research. It has similar effects to benzodiazepine drugs, but is structurally distinct and so is classed as a nonbenzodiazepine anxiolytic. The compound was developed by Merck, Sharp and Dohme. ...

* NS-2664 * NS-2710 * Pipequaline * RWJ-51204 *

SB-205,384 SB-205384 is an anxiolytic drug. It has similar effects to benzodiazepine drugs, but is structurally distinct and so is classed as a nonbenzodiazepine anxiolytic. SB-205384 is a GABAA positive allosteric modulator In pharmacology and biochem ...

* SX-3228 * TP-003 * TP-13 * TPA-023 * Y-23684

Pharmacology

The nonbenzodiazepines are positive allosteric modulators of the

GABA-A receptor The GABAA receptor (GABAAR) is an ionotropic receptor and ligand-gated ion channel. Its endogenous ligand is γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system. Upon opening, the GABAA receptor o ...

. Like the benzodiazepines, they exert their effects by binding to and activating the benzodiazepine site of the receptor complex. Many of these compounds are subtype selective providing novel

anxiolytics An anxiolytic (; also antipanic or antianxiety agent) is a medication or other intervention that reduces anxiety. This effect is in contrast to anxiogenic agents which increase anxiety. Anxiolytic medications are used for the treatment of anxiet ...

with little to no

hypnotic Hypnotic (from Greek ''Hypnos'', sleep), or soporific drugs, commonly known as sleeping pills, are a class of (and umbrella term for) psychoactive drugs whose primary function is to induce sleep (or surgical anesthesiaWhen used in anesthesia ...

and amnesiac effects and novel hypnotics with little or no anxiolytic effects.

Background

Nonbenzodiazepines have demonstrated efficacy in treating

sleep disorders A sleep disorder, or somnipathy, is a medical disorder of an individual's sleep patterns. Some sleep disorders are severe enough to interfere with normal physical, mental, social and emotional functioning. Polysomnography and actigraphy are tests ...

. There is some limited evidence that suggests that

tolerance Tolerance or toleration is the state of tolerating, or putting up with, conditionally. Economics, business, and politics * Toleration Party, a historic political party active in Connecticut * Tolerant Systems, the former name of Veritas Software ...

to nonbenzodiazepines is slower to develop than with

benzodiazepines Benzodiazepines (BZD, BDZ, BZs), sometimes called "benzos", are a class of depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, ...

. However, data is limited so no conclusions can be drawn. Data is also limited into the long-term effects of nonbenzodiazepines. Further research into the safety of nonbenzodiazepines and long-term effectiveness of nonbenzodiazepines has been recommended in a review of the literature. Some differences exist between the Z-drugs, for example

and

rebound effects The rebound effect, or rebound phenomenon, is the emergence or re-emergence of symptoms that were either absent or controlled while taking a medication, but appear when that same medication is discontinued, or reduced in dosage. In the case of re ...

may not occur with

zaleplon Zaleplon, sold under the brand names Sonata among others, is a sedative- hypnotic, used to treat insomnia. It is a nonbenzodiazepine hypnotic from the pyrazolopyrimidine class. It is manufactured by King Pharmaceuticals and Gedeon Richte ...

Pharmaceuticals

The first three nonbenzodiazepine drugs to enter the market were the "Z-drugs", zopiclone, zolpidem and zaleplon. These three drugs are all

sedative A sedative or tranquilliser is a substance that induces sedation by reducing irritability or excitement. They are CNS depressants and interact with brain activity causing its deceleration. Various kinds of sedatives can be distinguished, but ...

s used exclusively for the treatment of mild

insomnia Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, ...

. They are safer than the older

barbiturates Barbiturates are a class of depressant drugs that are chemically derived from barbituric acid. They are effective when used medically as anxiolytics, hypnotics, and anticonvulsants, but have physical and psychological addiction potential as we ...

especially in overdosage and they may, when compared to the benzodiazepines, have less of a tendency to induce

physical dependence Physical dependence is a physical condition caused by chronic use of a tolerance-forming drug, in which abrupt or gradual drug withdrawal causes unpleasant physical symptoms. Physical dependence can develop from low-dose therapeutic use of certai ...

and

addiction Addiction is a neuropsychological disorder characterized by a persistent and intense urge to engage in certain behaviors, one of which is the usage of a drug, despite substantial harm and other negative consequences. Repetitive drug use o ...

, although these issues can still become a problem. This has led to the Z-drugs becoming widely prescribed for the treatment of insomnia particularly in elderly patients. A little under a third (31%) of all Americans over 65 years of age are taking Z-drugs. Long-term use is not recommended as

and

can occur. A survey of patients using nonbenzodiazepine Z drugs and benzodiazepine hypnotic users found that there was no difference in reports of adverse effects that were reported in over 41% of users and, in fact, Z drug users were more likely to report that they had tried to quit their hypnotic drug and were more likely to want to stop taking Z drugs than benzodiazepine users. Efficacy also did not differ between benzodiazepine and Z drug users.

Side effects

The Z-drugs are not without disadvantages, and all three compounds are notable for producing side-effects such as pronounced

amnesia Amnesia is a deficit in memory caused by brain damage or disease,Gazzaniga, M., Ivry, R., & Mangun, G. (2009) Cognitive Neuroscience: The biology of the mind. New York: W.W. Norton & Company. but it can also be caused temporarily by the use ...

and more rarely

hallucinations A hallucination is a perception in the absence of an external stimulus that has the qualities of a real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space. Hallucination is a combinati ...

, especially when used in large doses. On rare occasions, these drugs can produce a fugue state, wherein the patient sleepwalks and may perform relatively complex actions, including cooking meals or driving cars, while effectively unconscious and with no recollection of the events upon awakening. While this effect is rare (and has also been reported to occur with some of the older sedative drugs such as

temazepam Temazepam (sold under the brand names Restoril among others) is a medication of the benzodiazepine class which is generally used to treat severe or debilitating insomnia. It is taken by mouth. Temazepam is rapidly absorbed, and significant hyp ...

and

secobarbital Secobarbital (as the sodium salt, originally marketed by Eli Lilly and Company for the treatment of insomnia, and subsequently by other companies as described below, under the brand name Seconal) is a short-acting barbiturate derivative drug that ...

), it can be potentially hazardous, and so further development of this class of drugs has continued in an effort to find new compounds with further improved profiles. Daytime withdrawal-related anxiety can also occur from chronic nightly nonbenzodiazepine hypnotic usage such as with

zopiclone Zopiclone, sold under the brand name Imovane among others, is a nonbenzodiazepine used to treat difficulty sleeping. Zopiclone is molecularly distinct from benzodiazepine drugs and is classed as a cyclopyrrolone. However, zopiclone increases th ...

. Side-effects can differ within the drug class due to differences in metabolism and pharmacology. For example, long-acting benzodiazepines have problems of drug accumulation especially in the elderly or those with liver disease, and shorter-acting benzodiazepines have a higher risk of more severe withdrawal symptoms. In the case of the nonbenzodiazepines,

may be the safest in terms of next-day sedation, and − unlike

zolpidem Zolpidem, sold under the brand name Ambien, among others, is a medication primarily used for the short-term treatment of sleeping problems. Guidelines recommend that it be used only after cognitive behavioral therapy for insomnia and behavior ...

and

− zaleplon has been found to have no association with increased motor vehicle accidents even when taken for

middle-of-the-night insomnia Middle-of-the-night insomnia (MOTN) is characterized by having difficulty returning to sleep after waking up during the night or very early in the morning. This kind of insomnia (sleeplessness) is different from initial or sleep-onset insomnia, whi ...

due to its ultrashort

elimination half-life Biological half-life (also known as elimination half-life, pharmacologic half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration ( Cmax) to half of Cmax in the b ...

Increased risk of depression

It has been claimed that insomnia causes depression and hypothesized that insomnia medications may help to treat depression. However, an analysis of data of clinical trials submitted to the

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

(FDA) concerning the drugs

, and

eszopiclone Eszopiclone, sold under the brand-name Lunesta among others such as Night Calm in Egypt, is a medication used in the treatment of insomnia. Evidence supports slight to moderate benefit up to six months. It is taken orally. Common side effects i ...

found that these sedative hypnotic drugs more than doubled the risks of developing depression compared to those taking placebo pills. Hypnotic drugs, therefore, may be contraindicated in patients with or at risk of depression. Hypnotics were found to be more likely to cause depression than to help it. Studies have found that long-term users of sedative hypnotic drugs have a markedly raised suicide risk as well as an overall increased mortality risk. Cognitive-behavioral therapy (CBT) for insomnia, on the other hand, has been found to both improve sleep quality as well as general mental health.

Other risks

Sleeping pills, including the Z-drugs, have been associated with an increased risk of death. In older people this family of medications increases the risk of

fractures Fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displ ...

and falls. The Z-drug

may have fewer side effects compared to benzodiazepines.

Dependence and withdrawal management

Nonbenzodiazepines should not be discontinued abruptly if taken for more than a few weeks due to the risk of

rebound withdrawal effects The rebound effect, or rebound phenomenon, is the emergence or re-emergence of symptoms that were either absent or controlled while taking a medication, but appear when that same medication is discontinued, or reduced in dosage. In the case of re ...

and acute withdrawal reactions, which may resemble those seen during

benzodiazepine withdrawal Benzodiazepine withdrawal syndrome often abbreviated to benzo withdrawal or BZD withdrawal is the cluster of signs and symptoms that may emerge when a person who has been taking benzodiazepines, either medically or recreationally develops a phy ...

. Treatment usually entails gradually reducing the dosage over a period of weeks or several months depending on the individual, dosage, and length of time the drug has been taken. If this approach fails, a crossover to a

benzodiazepine equivalent The below tables contain a sample list of benzodiazepines and benzodiazepine Analog (chemistry), analogs that are commonly prescribed, with their basic pharmacological characteristics, such as half-life and equivalent doses to other benzodiazepine ...

dose of a long-acting benzodiazepine (such as chlordiazepoxide or more preferably

diazepam Diazepam, first marketed as Valium, is a medicine of the benzodiazepine family that acts as an anxiolytic. It is commonly used to treat a range of conditions, including anxiety, seizures, alcohol withdrawal syndrome, muscle spasms, insomnia, ...

) can be tried followed by a gradual reduction in dosage. In extreme cases and, in particular, where severe addiction and/or abuse is manifested, an inpatient detoxification may be required, with

flumazenil Flumazenil (also known as flumazepil, code name Ro 15-1788) is a selective GABAA receptor antagonist administered via injection, otic insertion, or intranasally. Therapeutically, it acts as both an antagonist and antidote to benzodiazepines ( ...

as a possible detoxification tool.

Elderly

Nonbenzodiazepine

drugs, similar to benzodiazepines, cause impairments in body balance and standing steadiness upon waking; falls and hip fractures are frequently reported. The combination with alcohol increases these impairments. Partial but incomplete tolerance develops to these impairments. In general, nonbenzodiazepines are not recommended for older patients due to the increased risk of falls and fractures. An extensive review of the medical literature regarding the management of insomnia and the elderly found that there is considerable evidence of the effectiveness and lasting benefits of non-drug treatments for insomnia in adults of all age groups and that these interventions are underused. Compared with the benzodiazepines, the nonbenzodiazepine sedative-hypnotics offer little if any advantages in efficacy or tolerability in elderly persons. It was found that newer agents such as the melatonin agonists may be more suitable and effective for the management of chronic insomnia in elderly people. Long-term use of sedative-hypnotics for insomnia lacks an evidence base and is discouraged for reasons that include concerns about such potential adverse drug effects as cognitive impairment (

anterograde amnesia In neurology, anterograde amnesia is the inability to create new memories after the event that caused amnesia, leading to a partial or complete inability to recall the recent past, while long-term memories from before the event remain intact ...

), daytime sedation, motor incoordination, and increased risk of motor vehicle accidents and falls. In addition, the effectiveness and safety of long-term use of these agents remain to be determined. It was concluded that further research is needed to evaluate the long-term effects of treatment and the most appropriate management strategy for elderly persons with chronic insomnia.

Safety

A review of the literature regarding

s including the nonbenzodiazepine

Z drugs Nonbenzodiazepines (), sometimes referred to colloquially as Z-drugs (as many of their names begin with the letter "z"), are a class of psychoactive drugs that are very benzodiazepine-like in nature. They are used in the treatment of sleep problem ...

concluded that these drugs carry a significant risk to the individual. The risks include dependence, accidents, and other adverse effects. Gradual discontinuation of hypnotics may lead to improved health without worsening of sleep. It is preferred that they should be prescribed for only a few days at the lowest effective dose and avoided wherever possible in the elderly.

New compounds

More recently, a range of non-sedating

drugs derived from the same structural families as the Z-drugs have been developed, such as

alpidem Alpidem (Ananxyl) is an anxiolytic drug from the imidazopyridine family, related to the more well known sleeping medication zolpidem. Unlike zolpidem however, alpidem does not produce sedative effects at normal doses, and is instead used specific ...

(Ananyxl) and pagoclone, and approved for clinical prescription. Nonbenzodiazepine drugs are much more selective than the older

s, producing effective relief of anxiety/panic with little or no

sedation Sedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure. Examples of drugs which can be used for sedation include isoflurane, diethyl ether, ...

, or

anticonvulsant Anticonvulsants (also known as antiepileptic drugs or recently as antiseizure drugs) are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of ...

effects, and are thus potentially more precise than older, anti-anxiety drugs. However, anxiolytic nonbenzodiazepines are not widely prescribed and many have collapsed after initial clinical trials and consumption halted many projects, including but not limited to

, indiplon, and suriclone.

History

Z-drugs emerged in the last years of the 1980s and early 1990s, with

(Imovane) approved by the British

National Health Service The National Health Service (NHS) is the umbrella term for the publicly funded healthcare systems of the United Kingdom (UK). Since 1948, they have been funded out of general taxation. There are three systems which are referred to using the " ...

as early as 1989, quickly followed by

Sanofi Sanofi S.A. is a French multinational pharmaceutical and healthcare company headquartered in Paris, France. Originally, the corporation was established in 1973 and merged with Synthélabo in 1999 to form Sanofi-Synthélabo. In 2004, Sanofi-Syn ...

with

(Ambien). By 1999, King Pharmaceuticals had finalized approval with the American Food and Drug Administration (FDA) to market

(Sonata, Starnoc) across the US. In 2005, the FDA approved

(Lunesta) the (''S'')-

enantiomer In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical anti ...

of zopiclone. That same year, 2005, the FDA finalized approval for Ambien CR, or extended-release zolpidem. Most recently, in 2012 the FDA approved Intermezzo (zolpidem tartate sublingual), which is marketed for middle-of-the-night

, available in doses only half of the strength of immediate-release zolpidem tartrate to avoid residual next-day

References

External links

* https://web.archive.org/web/20071121225814/http://pharmacy.oregonstate.edu/drug_policy/pages/dur_board/reviews/articles/nonbenzodiazepine.html {{GABAAR PAMs Cyclopyrrolones Imidazopyridines Pyrazolopyrimidines GABAA receptor positive allosteric modulators Hypnotics Sedatives