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 (hypertension in combination with other anti hypertension medications). 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.
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. Equivalencies between individual benzodiazepines can differ by 400 fold on a mg per mg basis; awareness of this fact is necessary for the safe and effective use of benzodiazepines.
† Citation needed for this table.
|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||Helex, Xanax, Xanor, Onax, Alprox, Restyl, Tafil, Paxal||1-2||6–12 hours||anxiolytic||0.5 mg|
|Bretazenil||N/A||?||2.5 hours||anxiolytic, anticonvulsant||0.5 mg|
|Bromazepam||Lectopam, Lexotanil, Lexotan, Bromam||1-3||10–20 hours||anxiolytic||5-6 mg|
|Brotizolam||Lendormin, Dormex, Sintonal, Noctilan||0.5-2||4–5 hours||hypnotic||0.25 mg|
|Chlordiazepoxide||Librium, Risolid, Elenium||1.5-4||5–30 hours [36–200 hours]||anxiolytic||25 mg|
|Cinolazepam||Gerodorm||0.5-2||9 hours||hypnotic||40 mg|
|Clonazepam||Rivotril, Klonopin, Iktorivil, Paxam||1-4||18–50 hours||anxiolytic, anticonvulsant||0.5 mg|
|Clorazepate||Tranxene, Tranxilium||Variable||36–100 hours||anxiolytic, anticonvulsant||15 mg|
|Clotiazepam||Veratran, Clozan, Rize||1-3||6-18 hours||anxiolytic||5-10 mg|
|Cloxazolam||Sepazon, Olcadil||2-5 (?)||18–50 hours||anxiolytic, anticonvulsant||1 mg|
|Delorazepam||Dadumir||1-2||60–140 hours||anxiolytic||1 mg|
|Diazepam||Antenex, Apaurin, Apzepam, Apozepam, Hexalid, Pax, Stesolid, Stedon, Valium, Vival, Valaxona||1-1.5||20–100 hours [36-200]||anxiolytic, anticonvulsant, muscle relaxant||10 mg|
|Estazolam||ProSom||1-5||10–24 hours||hypnotic||2 mg|
|Etizolam||Etilaam, Pasaden, Depas||1-2||6 hours||anxiolytic, hypnotic||1 mg|
|Ethyl loflazepate||Victan, Meilax, Ronlax||1.5||50-100 hours||anxiolytic||2 mg|
|Flunitrazepam||Rohypnol, Fluscand, Flunipam, Ronal, Rohydorm,||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, anticonvulsant||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, Lorenin, Temesta, Tavor, Lorabenz||2-4||10–20 hours||anxiolytic, anticonvulsant||1 mg|
|Lormetazepam||Loramet, Noctamid, Pronoctan||0.5-2||10–12 hours||hypnotic||1.5 mg|
|Medazepam||Nobrium||?||36–200 hours||anxiolytic||10 mg|
|Midazolam||Dormicum, Versed, Hypnovel, Dormonid||0.5-1||3 hours (1.8–6 hours)||hypnotic, anticonvulsant||7.5 –15 mg|
|Nimetazepam||Erimin||0.5-3||14–30 hours||hypnotic||5 mg|
|Nitrazepam||Mogadon, Alodorm, Pacisyn, Dumolid, Nitrazadon||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, Oxabenz, Oxapax||3-4||4–15 hours||anxiolytic||30 mg|
|Phenazepam||Phenazepam||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||20 mg|
|Premazepam||N/A||2-6||10–13 hours||anxiolytic||3.75 mg|
|Quazepam||Doral||1-5||39–120 hours||hypnotic||20 mg|
|Temazepam||Restoril, Normison, Euhypnos, Temaze, Tenox||0.5-3||8–22 hours||hypnotic||20 mg|
|Tetrazepam||Mylostan||1-3||3–26 hours||Skeletal muscle relaxant||100 mg|
|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|
|Eszopiclone§||Lunesta||6 hours||hypnotic||3 mg|
|Zaleplon§||Sonata, Starnoc||1 hours||hypnotic||20 mg|
|Zolpidem§||Ambien, Nytamel, Stilnoct, Stilnox, Xolnox, Zoldem, Zolnod||2.6 hours||hypnotic||20 mg|
|Zopiclone§||Imovane, Rhovane, Ximovan; 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.
§ 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.
‡There has been an ongoing debate about the length of use and potency factors of benzodiazapines in the UK. For this reason, The Ashton Manual should not be used for Wikipedia, as it does not present a worldwide view on this subject. The Ashton Manual keeps switching the potency of Alprazolam and Clonazepam to .05 mgs (equivalent to 10 mgs of Diazepam) , when they have long been known to be 1 mg. The UK is attempting to get a 2-4 week prescribing maximum on benzodiazapines. See http://www.benzo.org.uk/appg.htm for more information. Also compare the UK's Ashton chart with the chart at http://www.psychresidentonline.com/Benzodiazepine%20Comparison.htm and you can see how the Ashton chart does not represent a worldwide view on this topic.
‡See also http://www.csam-asam.org/sites/default/files/pdf/misc/TIP_45.pdf, Page 76. US Department of Health and Human Services, 2006. States that 10 mg Valium= 1 mg Xanax, 2 mg of Klonopin, and 2 mg of Ativan. (United States Department of Health guidelines)
‡See also https://docs.google.com/viewer?a=v&q=cache:kIztmpST_isJ:www.health.qld.gov.au/atod/documents/24904.pdf+&hl=en&gl=us&pid=bl&srcid=ADGEESgmtqb6fHK5OVeXBdK8Zi_hJvaAyLSvEYXO0_8Ojc9JixlkOEIztMkXSGfN_eyPTkEu8NFLuzZuOgf6nkgTgku9nbNj__s6nYv_aH-1ZNynIuO8ssp1sRY3TN4MNyDKoZOOTRkI&sig=AHIEtbRJIodYaXE41qdLwOxivtqUfjbS_Q; Table 11, Section 5.8. It notes that 10 mg of Valium is equivalent to 1mg of Xanax and .50-1 mg of Klonopin. (Australian view)
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