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The below tables contain a list of benzodiazepines that are commonly prescribed, with their basic pharmacological characteristics such as half-life and equivalent doses to other benzodiazepines also listed, along with their trade names and primary uses. The elimination half life is how long it takes for half of the drug to be eliminated by the body. "Time to peak" refers to when maximum levels of the drug in the blood occur after a given dose. Benzodiazepines generally share the same pharmacological properties, such as anxiolytic, sedative, hypnotic, skeletal muscle relaxant, amnesic and anticonvulsant, but some variation in potency of certain effects may exist among individual benzodiazepines. Some benzodiazepines produce active metabolites. Active metabolites are produced when a person's body metabolizes the drug into compounds that share a similar pharmacological profile to the parent compound and thus are relevant when calculating how long the pharmacological effects of a drug will last. Long-acting benzodiazepines with long-acting active metabolites such as diazepam and chlordiazepoxide are often prescribed for benzodiazepine or alcohol withdrawal or for anxiety if constant dose levels are required throughout the day. Shorter-acting benzodiazepines are often preferred for insomnia due to their lesser hangover effect.[1][2][3][4][5]

Benzodiazepine half life and equivalent dose table

It is important to note that the elimination half life of diazepam and chlordiazepoxide as well as other long half-life benzodiazepines is twice as long in the elderly compared to younger individuals. Individuals with an impaired liver also metabolise benzodiazepines more slowly. Many doctors make the mistake of not adjusting benzodiazepine dosage according to age in elderly patients. Thus the equivalent doses below may need to be adjusted accordingly in individuals on short acting benzodiazepines who metabolise long-acting benzodiazepines more slowly and vice versa. The changes are most notable with long acting benzodiazepines as these are prone to significant accumulation in such individuals. For example the equivalent dose of diazepam in an elderly individual on lorazepam may be up to half of what would be expected in a younger individual.[6][7]

Drug Name Common Brand Names* Time to Peak (Onset of action in hours) Elimination Half-Life (h) [active metabolite] Therapeutic use Approximate Equivalent Dose
Alprazolam Xanax, Xanor, Tafil, Alprox, Frontal (Brazil) 1-2 6-12 hours anxiolytic 0.5 mg
Bromazepam Lexotanil, Lexotan, Lexomil, Somalium, Bromam 1-3 10-20 hours anxiolytic 5-6 mg
Chlordiazepoxide Librium, Tropium, Risolid, Klopoxid 1.5-4 5-30 hours [36-200 hours] anxiolytic 25 mg
Cinolazepam Gerodorm .5-2 9 h hypnotic 40 mg
Clonazepam Klonopin, Rivotril, Iktorivil 1-4 18-50 hours anxiolytic, anticonvulsant 0.5 mg
Cloxazolam Olcadil (Brazil) 2-5 (?) 18-50 hours anxiolytic, anticonvulsant 1 mg
Clorazepate Tranxene Variable [36-100 hours] anxiolytic, anticonvulsant 15 mg
Diazepam Valium, Pax (South Africa), Apzepam, Stesolid, Vival, Apozepam, Hexalid, , Stedon, Valaxona 1-2 20-100 hours [36-200] anxiolytic, anticonvulsant, muscle relaxant 10 mg
Estazolam ProSom 0.5-5 10-24 h hypnotic 1-2 mg
Flunitrazepam Rohypnol, Fluscand, Flunipam, Ronal, Rohydorm (Brazil) 0.5-3 18-26 hours [36-200 hours] hypnotic 1 mg
Flurazepam Dalmadorm, Dalmane 1-1.5 [40-250 hours] hypnotic 15-30 mg
Flutoprazepam Restas 0.5-9 60-90 hours hypnotic 2-3 mg
Halazepam Paxipam 1-3 [30-100 hours] anxiolytic 20-40 mg
Ketazolam Anxon 2.5-3 30-100 hours [36-200] anxiolytic 15-30 mg
Loprazolam Dormonoct 0.5-4 6-12 hours hypnotic 1-2 mg
Lorazepam Ativan, Temesta, Tavor, Lorabenz 2-4 10-20 hours anxiolytic,anticonvulsant 1 mg
Lormetazepam Loramet, Noctamid, Pronoctan 0.5-2 10-12 hours hypnotic 1-2 mg
Medazepam Nobrium ? 36-200 hours anxiolytic 10 mg
Midazolam Dormicum, Versed, Hypnovel, Dormonid (Brazil) 0.5-1 3 hours (1.8-6 hours) hypnotic 5 -8mg[8]
Nimetazepam Erimin 0.5-3 14-30 hours hypnotic 5 mg
Nitrazepam Mogadon, Alodorm, Pacisyn, Dumolid 0.5-7 15-38 hours hypnotic, anticonvulsant 10 mg
Nordazepam Madar, Stilny ? 50-120 hours anxiolytic 10 mg
Oxazepam Seresta, Serax, Serenid, Serepax, Sobril, Oxascand, Alopam, Oxabenz, Oxapax 3-4 4-15 hours anxiolytic 30 mg
Phenazepam феназепам 1.5-4 60 hours anxiolytic, anticonvulsant 1 mg
Pinazepam Domar ? 40-100 hours anxiolytic 20 mg
Prazepam Lysanxia, Centrax 2-6 36-200 hours anxiolytic 10-20 mg
Premazepam 1 2-6 10-13 hours anxiolytic 3.75 mg
Quazepam Doral 1-5 39-120 hours hypnotic 20 mg
Temazepam Restoril, Normison, Euhypnos, Tenox 0.5-3 8-22 hours hypnotic 20 mg
Tetrazepam Mylostan 1-3 3-26 hours Skeletal muscle relaxant 100mg
Triazolam Halcion, Rilamir 0.5-2 2 hours hypnotic 0.25 mg

Atypical benzodiazepine receptor ligands

Drug Name Common Brand Names* Elimination Half-Life (h) [active metabolite] Primary Effects Approximate Equivalent Dose
Clobazam Frisium, Urbanol 8-60 hours anxiolytic, anticonvulsant 20 mg
DMCM ? ? anxiogenic, convulsant Non-applicable
Flumazenil Anexate, Lanexat, Mazicon, Romazicon 1 hour antidote Typical dose 0.2 - 0.6 mgð

§ || Lunesta || 6 hours || hypnotic || 3 mg


§ || Sonata, Starnoc || 1 hours || hypnotic || 20 mg


§ || Ambien, Nytamel, Stilnoct, Stilnox, Zoldem, Zolnod || 2.6 hours || hypnotic || 20 mg


§ || Imovane, Rhovane, Zileze; Zimoclone; Zimovane; Zopitan; Zorclone, || 4-6 hours || hypnotic || 15 mg

* Not all trade names are listed. Click on drug name to see a more comprehensive list.
The duration of apparent action is usually considerably less than the half-life. With most benzodiazepines, noticeable effects usually wear off within a few hours. Nevertheless, as long as the drug is present it will exert subtle effects within the body. These effects may become apparent during continued use or may appear as withdrawal symptoms when dosage is reduced or the drug is stopped.
Equivalent doses are based on clinical experience but may vary between individuals.[1]
§ The molecular structure of these drugs differs from the benzodiazepine molecule but they work on benzodiazepine receptors with the same or similar effects and are cross tolerant drugs.
ð Flumazenil is given to reverse the effects of benzodiazepines and similar drugs, and dosage range listed will vary depending on which drug is being counteracted, what dosage the first drug was given in, and whether the flumazenil is given to actually reverse overdose or just to reduce side effects.

See also


  1. Golombok S, Lader M (August 1984). The psychopharmacological effects of premazepam, diazepam and placebo in healthy human subjects. Br J Clin Pharmacol 18 (2): 127–33.
  2. de Visser SJ, van der Post JP, de Waal PP, Cornet F, Cohen AF, van Gerven JM (January 2003). Biomarkers for the effects of benzodiazepines in healthy volunteers. Br J Clin Pharmacol 55 (1): 39–50.
  3. Benzodiazepine Names. URL accessed on 2009-04-05.
  4. C. Heather Ashton (2007). Benzodiazepine Equivalence Table. URL accessed on 2009-04-05.
  5. Bob, Dr (1995). Benzodiazepine Equivalence Charts. URL accessed on 2009-04-05.
  6. (15 May 2004) Clinical geriatric psychopharmacology, 4th, 450–453, USA: Lippincott Williams & Wilkins.
  7. Delcò F, Tchambaz L, Schlienger R, Drewe J, Krähenbühl S (2005). Dose adjustment in patients with liver disease. Drug Saf 28 (6): 529–45.
  8. Sostmann HJ, Sostmann H, Crevoisier C, Bircher J (1989). Dose equivalence of midazolam and triazolam. A psychometric study based on flicker sensitivity, reaction time and digit symbol substitution test. Eur. J. Clin. Pharmacol. 36 (2): 181–7.

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