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The core structure of benzodiazepines. "R" labels denote common locations of side chains, which give different benzodiazepines their unique properties.
The below tables contain a sample 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.
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[who?] make the mistake of not adjusting benzodiazepine dosage according to age in elderly patients. Thus the approximate 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.[this quote needs a citation] 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.
per Ashton "Benzodiazepine Equivalency 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,||1-2||9–20 hours||anxiolytic||1 mg|
|Bretazenil||N/A||?||2.5 hours||anxiolytic, anticonvulsant||0.5 mg|
|Bromazepam||Lectopam, Lexaurin, 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||sedative||40 mg|
|Clonazepam||Rivatril, 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|
|Diclazepam||N/A||1.5-4 (4-6)||42–220 hours [10–200 (metabolites)]||anxiolytic, anticonvulsant, hypnotic muscle relaxant, sedative, skeletal muscle relaxant||1-1.5 mg|
|Estazolam||ProSom||1-5||10–24 hours||hypnotic||2 mg|
|Etizolam||Etilaam, Etizest, Pasaden, Depas||1-2||6 hours||anxiolytic, hypnotic||1 mg|
|Ethyl loflazepate||Victan, Meilax, Ronlax||1.5||50–100 hours||anxiolytic||2 mg|
|Flubromazepam||N/A||1.5-4 (4-8)||100–220 hours||anxiolytic, anticonvulsant, hypnotic muscle relaxant, sedative||4-6 mg|
|Flunitrazepam||Rohypnol, Hipnosedon, Vulbegal, 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||2 mg|
|Lorazepam||Ativan, Lorenin, Lorsilan, 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, Ansilan, Mezapam, Rudotel, Raporan||?||36–200 hours||anxiolytic||10 mg|
|Midazolam||Dormicum, Versed, Hypnovel, Dormonid||0.5-1||3 hours (1.8–6 hours)||hypnotic, anticonvulsant||7.5 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, Opamox||3-4||4–15 hours||anxiolytic||20 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||15 mg|
|Pyrazolam||N/A||1-1.5||16-18 hours||anxiolytic||1 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||Myolastan||1-3||3–26 hours||Skeletal muscle relaxant||100 mg|
|Triazolam||Halcion, Rilamir||0.5-2||2 hours||hypnotic||0.25 (.5 with oral bioavailability) mg|
|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|
|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, Sanval, Stilnoct, Stilnox, Sublinox (Canada), 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.
‡ Equivalent doses are based on clinical experience but may vary between individuals. http://www.benzo.org.uk/bzequiv.htm.
** Flumazenil is an imidazobenzodiazepine derivative, and in layman's terms, it is a benzodiazepine overdose antidote that is given intravenously in Intensive Care Units (ICUs) to reverse the effects of benzodiazepine overdoses, as well for overdoses of the non-benzodiazepine "Z-drugs" such as Ambien and Lunesta. Flumazenil is contraindicated for benzodiazepine-tolerant patients in overdose cases. In such cases, the risks far outweigh the benefits, which include potential and severe seizures. The method by which Flumazenil acts to prevent non-benzodiazepine tolerant overdose from causing potential harm is via preventing the benzodiazepines and Z-drugs from binding to the GABAA receptors via competitive inhibition which the Flumazenil creates. Clinical observation notating the patient's oxygen levels, respiratory, heart and blood pressure rates are used, as they are much safer than the potential seizure effects from Flumazenil. Supportive care to mediate any problems resulting from abnormal rates of the pulmonary, respiratory, and cardiovascular systems is typically the only treatment that is required in benzodiazepine-only overdoses. In most cases, activated charcoal/carbon is often used to prevent benzodiazepines from being absorbed by the gastrointestinal tract, and the use of stomach-pumping/gastric lavage is no longer commonly used nor suggested by some toxicologists. Even in cases where other central nervous system (CSN) depressants (such as in combined benzodiazepine and tricyclic antidepressant/TCA overdoses) are detected and/or suspected, endotrachial intubation for the airway path and supportive oxygen are typically implemented and are much safer than Flumazenil.
The Ashton Manual claims the potency of both Alprazolam and Clonazepam to be 0.5 mg equivalent to 10 mg of diazepam/Valium, whereas most sources give 1 mg equivalent to 10 mg diazepam.
Another chart with different ratios can be seen at www.health.qld.gov.au/atod/documents/24904.pdf; Table 11, Section 5.8. It notes that 10 mg of Valium is equivalent to 1 mg of Xanax/Alprazolam and .50 – 1 mg of Klonopin/Clonazepam/Rivotril. (Australian Department of Health)
The UK's House of Commons began APPGITA/The All Party Parliamentary Group on Involuntary Tranquilliser Addiction. Since 2002, APPGITA has tried to politically mandate prescribing guidelines for benzodiazepines. APPGITA has attempted to get a two to four week limit mandate for prescribing benzodiazepines to replace the two to four week benzodiazepine prescribing guidelines, which are merely recommended.