3-Hydroxyphenazepam is a benzodiazepine with hypnotic, sedative, anxiolytic, and anticonvulsant properties.[1] It is an active metabolite of phenazepam,[1][2] as well as the active metabolite of the benzodiazepine prodrug cinazepam.[3] Relative to phenazepam, 3-hydroxyphenazepam has diminished myorelaxant properties, but is about equivalent in most other regards.[1] Like other benzodiazepines, 3-hydroxyphenazepam behaves as a positive allosteric modulator of the benzodiazepine site of the GABAA receptor with an EC50 value of 10.3 nM.[4][5][6] It has been sold online as a designer drug.[7][8][9][10]

3-Hydroxyphenazepam ball-and-stick model
Clinical data
ATC code
  • None
Legal status
Legal status
CAS Number
PubChem CID
Chemical and physical data
Molar mass365.609 g/mol g·mol−1
3D model (JSmol)

See also


  1. ^ a b c Artur Viktorovich Valʹdman (31 May 1986). Drug dependence and emotional behavior: neurophysiological and neurochemical approaches. Consultants Bureau. ISBN 978-0-306-10984-3.
  2. ^ Lukasz Komsta; Monika Waksmundzka-Hajnos; Joseph Sherma (20 December 2013). Thin Layer Chromatography in Drug Analysis. CRC Press. pp. 299–. ISBN 978-1-4665-0715-9.
  3. ^ Schukin SI, Zinkovsky VG, Zhuk OV (2011). "Elimination kinetics of the novel prodrug cinazepam possessing psychotropic activity in mice" (PDF). Pharmacol Rep. 63 (5): 1093–100. doi:10.1016/s1734-1140(11)70628-4. PMID 22180351.
  4. ^ "Phenazepam Pre-Review Report" (PDF). World Health Organisation (WHO). November 2015.
  5. ^ Kopanitsa, M. V.; Zbarska, S. M.; Boychuk, Ya. A.; Krishtal, O. A. (2000). "Modulation of GABA-activated currents by phenazepam and its metabolites in isolated rat purkinje neurons". Neurophysiology. 32 (3): 192. doi:10.1007/BF02506568. ISSN 0090-2977.
  6. ^ Golovenko, N. Ya; Larionov, V. B. (2014). "Pharmacodynamical and Neuroreceptor Analysis of the Permeability of the Blood-Brain Barrier for Derivatives of 1,4-Benzodiazepine". Neurophysiology. 46 (3): 199–205. doi:10.1007/s11062-014-9429-2. ISSN 0090-2977.
  7. ^ "3-hydroxyphenazepam". New Synthetic Drugs Database. Archived from the original on 2016-09-28. Retrieved 2016-05-30.
  8. ^ Madeleine Pettersson Bergstrand; Anders Helander; Therese Hansson; Olof Beck (2016). "Detectability of designer benzodiazepines in CEDIA, EMIT II Plus, HEIA, and KIMS II immunochemical screening assays". Drug Testing and Analysis. 9 (4): 640–645. doi:10.1002/dta.2003. PMID 27366870.
  9. ^ Moosmann, Bjoern; Bisel, Philippe; Franz, Florian; Huppertz, Laura M.; Auwärter, Volker (2016). "Characterization and in vitro phase I microsomal metabolism of designer benzodiazepines – an update comprising adinazolam, cloniprazepam, fonazepam, 3-hydroxyphenazepam, metizolam, and nitrazolam". Journal of Mass Spectrometry. 51 (11): 1080–1089. doi:10.1002/jms.3840. ISSN 1096-9888. PMID 27535017.
  10. ^ Manchester, Kieran R.; Maskell, Peter D.; Waters, Laura (2018). "Experimental versus theoretical log D7.4, pKa and plasma protein binding values for benzodiazepines appearing as new psychoactive substances". Drug Testing and Analysis. 10 (8): 1258–1269. doi:10.1002/dta.2387. ISSN 1942-7611. PMID 29582576.

Adinazolam (marketed under the brand name Deracyn) is a benzodiazepine derivative, and more specifically, a triazolobenzodiazepine (TBZD). It possesses anxiolytic, anticonvulsant, sedative, and antidepressant properties. Adinazolam was developed by Dr. Jackson B. Hester, who was seeking to enhance the antidepressant properties of alprazolam, which he also developed. Adinazolam was never FDA approved and never made available to the public market, however it has been sold as a designer drug.


Aprobarbital (or aprobarbitone), sold as Oramon, Somnifaine, and Allonal, is a barbiturate derivative invented in the 1920s by Ernst Preiswerk. It has sedative, hypnotic and anticonvulsant properties, and was used primarily for the treatment of insomnia. Aprobarbital was never as widely used as more common barbiturate derivatives such as phenobarbital and is now rarely prescribed as it has been replaced by newer drugs with a better safety margin.

See also: Alphenal


CGS-8216 is an anxiolytic pyrazoloquinoline.


Cinazepam (BD-798, sold under brand name Levana) is an atypical benzodiazepine derivative. It produces pronounced hypnotic, sedative, and anxiolytic effects with minimal myorelaxant side effects. In addition, unlike many other benzodiazepine and nonbenzodiazepine hypnotics such as diazepam, flunitrazepam, and zopiclone, cinazepam does not violate sleep architecture, and the continuity of slow-wave sleep and REM sleep are proportionally increased. As such, cinazepam produces a sleep state close to physiological, and for that reason, may be advantageous compared to other, related drugs in the treatment of insomnia and other sleep disorders.Cinazepam has an order of magnitude lower affinity for the benzodiazepine receptor of the GABAA complex relative to other well-known hypnotic benzodiazepines such as nitrazepam and phenazepam. Moreover, in mice, it is rapidly metabolized, with only 5% of the base compound remaining within 30 minutes of administration. As such, cinazepam is considered to be a benzodiazepine prodrug; specifically, to 3-hydroxyphenazepam, as the main active metabolite.


Clazolam (SAH-1123), also referred to as isoquinazepon, is a drug which is a fused benzodiazepine and tetrahydroisoquinoline derivative. It was developed in the 1960s but was never marketed. It possesses anxiolytic effects and is also claimed to have antidepressant properties.


Cloniprazepam is a benzodiazepine derivative and a prodrug mainly for clonazepam (a patented medicine) and other metabolites., including 7-aminoclonazepam and clonazepam mentioned above (both as metabolites), which may be misinterpreted as clonazepam intake at the result of a drug test.Some of the minor metabolites include 3-hydroxy and 6-hydroxyclonazepam, 3-hydroxycloniprazepam and ketocloniprazepam with ketone group formed where 3-hydroxy group was.It is a designer drug and an NPS (short for "new psychoactive substance"). At the end of 2017, cloniprazepam remains an uncontrolled substance in most of the countries.


Etazepine (INN) is an anticonvulsant with a tricyclic structure which is related to the benzodiazepines, but was never marketed. It appears to exert its effects via acting through the GABAergic system.


Flubromazolam (JYI-73) is a benzodiazepine derivative closely related to triazolam and flubromazepam that has been sold online as a designer drug. Flubromazolam is reputed to be highly potent, and concerns have been raised that clonazolam and flubromazolam in particular may pose comparatively higher risks than other designer benzodiazepines, due to their ability to produce strong sedation and amnesia at oral doses of as little as 0.5 mg. Life-threatening adverse reactions have been observed at doses of only 3 mg of flubromazolam.


Heptobarbital (Rutonal), also known as phenylmethylbarbituric acid is a barbiturate derivative. It has often been confused with methylphenobarbital because both drugs contain a methylphenyl moiety and are overall very similar in structure.


Meclonazepam ((S)-3-methylclonazepam) was discovered by a team at Hoffmann-La Roche in the 1970s and is a drug which is a benzodiazepine derivative similar in structure to clonazepam. It has sedative and anxiolytic actions like those of other benzodiazepines, and also has anti-parasitic effects against the parasitic worm Schistosoma mansoni.Meclonazepam was never used as medicine and instead appeared online as a designer drug.


Metizolam (also known as desmethyletizolam) is a thienotriazolodiazepine that is the demethylated analogue of the closely related etizolam.


Nealbarbital (Censedal) is a barbiturate derivative developed by Aktiebolaget Pharmacia in the 1950s. It has sedative and hypnotic effects, and was used for the treatment of insomnia.


Nitemazepam (or 3-hydroxynimetazepam) is a benzodiazepine derivative which was first synthesised in the 1970s but was never marketed. It is the 3-hydroxy derivative of nimetazepam, and an active metabolite. It is also the 7-nitro instead of 7-chloro analogue of temazepam. It has in more recent years been sold as a designer drug, first being definitively identified in Europe in 2017.


Nitrazepate (Lorzem) is a drug which is a benzodiazepine derivative and has anxiolytic properties. It is normally produced as its potassium salt, potassium nitrazepate.


Nitrazolam is a benzodiazepine that has been sold online as a designer drug.It is closely related to clonazolam, only differing by the removal of a chlorine group at the benzene ring.

A study in mice indicated that nitrazolam can be several times more potent than diazepam as an antagonist of electroshock-induced tonic-extensor convulsions but less potent than diazepam at preventing the righting reflex.Nitrazolam has been used as an example compound to demonstrate the microscale synthesis of reference materials utilizing polymer‐supported reagents.


Nortetrazepam is a drug which is a benzodiazepine derivative, one of the major metabolites of tetrazepam.


Obovatol is a biphenolic anti-inflammatory, anxiolytic, and nootropic isolated from the bark of Magnolia obovata. It is a biphenyl lignan.


Reclazepam is a drug which is a benzodiazepine derivative. It has sedative and anxiolytic effects similar to those produced by other benzodiazepine derivatives, and has a short duration of action.


Styramate is a muscle relaxant and anticonvulsant drug. At therapeutic doses, it does not produce significant sedative effects.

Benzodiazepine prodrugs
Kava constituents
Neuroactive steroids

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