Kekulé, skeletal formula of a phenazepam minor tautomer Spacefill model of a phenazepam minor tautomer
CAS number  N
PubChem  YesY
ChemSpider  YesY
Jmol-3D images Image 1
Image 2
Molecular formula C15H10BrClN2O
Molar mass 349.61 g mol−1
60 hr[1]
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N   YesY/N?)

Phenazepam is a benzodiazepine drug, which was developed in the Soviet Union in 1974 and now produced in Russia and some CIS countries. Phenazepam is used in the treatment of neurological disorders such as epilepsy, alcohol withdrawal syndrome and insomnia. It can be used as a premedication before surgery as it augments the effects of anesthetics and reduces anxiety. Recently, phenazepam has gained popularity as a recreational drug; misuse has been reported in the United Kingdom,[2] Finland,[3] Sweden,[4] and the United States.[5]


  • Dosage 1
  • Side effects 2
  • Contraindications and special caution 3
  • Detection in biological fluids 4
  • Legal status 5
    • United States 5.1
    • United Kingdom 5.2
    • Elsewhere 5.3
  • See also 6
  • References 7


An average phenazepam dosage is 0.5 mg 2-3 times daily. The maximum daily dosage must not exceed 10 mg. 1 mg of phenazepam is thought to be equivalent to 10 mg of diazepam.

Side effects

Side effects include hiccups, dizziness, loss of coordination and drowsiness, along with anterograde amnesia which can be quite pronounced at high doses.[6] As with other benzodiazepines, in case of abrupt discontinuation following prolonged use, severe withdrawal symptoms may occur including restlessness, anxiety, insomnia, seizures, convulsions and death, though because of its long half-life, these withdrawal symptoms may take two or more days to manifest].

Contraindications and special caution

Benzodiazepines require special precaution if used in the elderly, during pregnancy, in children, alcohol or drug-dependent individuals and individuals with comorbid psychiatric disorders.[7]

Phenazepam should not be taken with alcohol or any other CNS depressants. Phenazepam should not be used therapeutically for periods of longer than one month including tapering on and off the drug as recommended for any benzodiazepine in the British national formulary. Some patients may require longer term treatment.

Phenazepam was found to be a component in some herbal incense mixtures in Australia & New Zealand in 2011, namely "Kronic". The particular product variety was withdrawn shortly from the market after and replaced with a new formulation.[8]

Detection in biological fluids

Phenazepam may be measured in blood or plasma by chromatographic methods. Blood phenazepam concentrations are typically less than 30 μg/L during therapeutic usage, but have frequently been in the 100-600 μg/L range in automotive vehicle operators arrested for impaired driving ability.[9]

Legal status

United States

Under federal United States law, phenazepam is not currently classified as a controlled substance, as the Federal Analog Act only provides for automatic assumed classification of chemicals "substantially similar" to existing Schedule I or Schedule II drugs, whereas all controlled benzodiazepines under the Controlled Substances Act are classified as Schedule IV. Although phenazepam is currently not controlled, sale for human use remains illegal in the United States. Manufacturers circumvent this regulation via a "Not for human use" disclaimer on the product's label, providing a legal loophole as products not intended for human consumption are exempt from FDA approval.

Individual states in the United States often ban these analog drugs by name as they appear. On May 21, 2012, Louisiana state Governor Bobby Jindal approved legislation classifying phenazepam as a controlled dangerous substance.[10] This ban affected several products, some of which were sold at retail stores under the guise of air freshener or similar, containing phenazepam yet claiming not to be for human use. This legislation was introduced after one such product, branded as "Zannie" and marketed as an air freshener rapidly gained publicity as the subject of numerous media reports, attracting the attention of officials. The ensuing investigation effort, led by Senator Fred Mills and Louisiana Poison Center Director Dr. Mark Ryan, positively identified the active ingredient of "Zannie" as phenazepam. According to Dr. Ryan, chemical analysis identified the active ingredient as "100 percent phenazepam".[10]

Dr. Paul Halverson, director and state health officer for the Arkansas Department of Health, approved an emergency rule to ban the sale and distribution of phenazepam shortly after the Louisiana ban. The actions in Louisiana and Arkansas add this drug as a Schedule I Controlled Substance. Schedule I Controlled Substances have no approved medical use in the United States and include substances of high abuse.Citation Needed Despite its general legality in all other states, sale for human consumption is illegal.

United Kingdom

Phenazepam is a class C drug in the UK.[11]

The UK home office banned importation of phenazepam on Friday 22 July 2011[12] while it drafted legislation, released in January 2012[13] to become law at the end of March 2012.[14] The bill was quashed following advice from the ACMD as it included two non-abusable steroids.[15] There was a new discussion about its fate on April 23, 2012, where it was decided that the bill would be rewritten and phenazepam would still be banned.[16]

It was eventually banned on June 13, 2012 as a class C, schedule II drug.[17]


Phenazepam was not scheduled in Finland in 2012.[3]

Phenazepam is considered a narcotic in Norway, as per a March 23, 2010 Health Department addition to the Regular Narcotic List.

In Russia, while the drug is considered a prescription medication (but not a controlled one, as all other benzodiazepines), some pharmacies sell it without prescriptions required.

See also


  1. ^ Species differences in phenazepam kinetics and metabolism, National Center for Biotechnology Information, USA
  2. ^ Corkery, J. M.; Schifano, F.; Ghodse, A. H. (2012). "Phenazepam abuse in the UK: An emerging problem causing serious adverse health problems, including death". Human Psychopharmacology: Clinical and Experimental 27 (3): 254.  
  3. ^ a b Kriikku, P.; Wilhelm, L.; Rintatalo, J.; Hurme, J.; Kramer, J.; Ojanperä, I. (2012). "Phenazepam abuse in Finland: Findings from apprehended drivers, post-mortem cases and police confiscations". Forensic Science International.  
  4. ^ Mrozkowska, J.; Vinge, E.; Borna, C. (2009). "Abuse of phenazepam--new phenomenon in Sweden. Benzodiazepine derivative from Russia caused severe intoxication". Lakartidningen 106 (8): 516–517.  
  5. ^ Maskell, P. D.; De Paoli, G.; Nitin Seetohul, L.; Pounder, D. J. (2012). "Phenazepam: The drug that came in from the cold". Journal of Forensic and Legal Medicine 19 (3): 122–125.  
  6. ^ Stephenson, Jon; David Golz; Mary Jo Brasher (January 2013). "Phenazepam and its effects on driving". Journal of Analytical Toxicology 37 (1): 25–29.  
  7. ^ Authier, N.; Balayssac, D.; Sautereau, M.; Zangarelli, A.; Courty, P.; Somogyi, A. A.; Vennat, B.; Llorca, P. -M.; Eschalier, A. (2009). "Benzodiazepine dependence: Focus on withdrawal syndrome". Annales Pharmaceutiques Françaises 67 (6): 408–13.  
  8. ^ Couch, R. A. F.; Madhavaram, H. (2012). "Phenazepam and cannabinomimetics sold as herbal highs in New Zealand". Drug Testing and Analysis 4 (6): 409–414.  
  9. ^ , 9th edition, Biomedical Publications, Seal Beach, CA, 2011, pp. 1320-1321.Disposition of Toxic Drugs and Chemicals in ManR. Baselt,
  10. ^ a b "Bill to Ban Zannie Passes". KSLA 12. 2012-05-21. Retrieved 2012-05-21. 
  11. ^ "PHENAZEPAM". Talk To Frank. Retrieved 2013-02-11. 
  12. ^ "Phenazepam / Home Office". UK Home Office. 2012-04-12. Retrieved 2013-02-11. 
  13. ^ "The Misuse of Drugs Act 1971 (Amendment) Order 2012" (PDF). UK Home Office. 2012-01-27. Retrieved 2012-03-11. 
  14. ^ "Letter from Lord Henly to the ACMD" (PDF). UK Home Office. 2012-01-27. Retrieved 2012-03-11. 
  15. ^ "ACMD letter on further advice on the classification of two steroidal substances - February 2012" (PDF). UK Home Office. 2012-02-14. Retrieved 2012-03-18. 
  16. ^ "Draft Misuse of Drugs Act 1971 (Amendment) Order 2012". UK Home Office. 2012-04-23. Retrieved 2012-05-04. 
  17. ^ "A Change to the Misuse of Drugs Act 1971: control of pipradrol-related compounds and phenazepam". UK Home Office. 7 Jun 2012. Retrieved 2012-07-30.