Benzodiazepines are a class of medications commonly prescribed for anxiety, insomnia, and seizure disorders. Understanding the differences between various benzodiazepines is crucial for healthcare professionals and patients alike. The “Benzo Strength Chart” serves as a valuable tool, offering a comparative overview of these medications based on key pharmacological properties. This guide delves into a benzodiazepine comparison chart, highlighting variations in onset of action, half-life, and comparative oral doses.
| Benzodiazepine | Onset of Action (min) | Half-life* (hrs) | Comp. Oral Dose** (Ashton) | Comp. Oral Dose** (ClinCalc) |
|---|---|---|---|---|
| Alprazolam (Xanax®) | 15-30 | 6-20 | 0.5 mg | 0.75 mg (0.5 – 2 mg) |
| Bromazepam (Lexotan®) | 15-30 | 8-30 | 3 mg | – |
| Chlordiazepoxide (Librium®) | 15-30 | 5-100 | 10 mg | 33 mg (12 – 50 mg) |
| Clobazam (Onfi®)*** | 20-30 | 42-47 | 20 mg | – |
| Clonazepam (Klonopin®) | 15-30 | 18-39 | 0.5 mg | 0.75mg (0.5 – 4 mg) |
| Clorazepate (Tranxene®) | 15-30 | 50-100 | 7.5 mg | 13 mg (8 – 30 mg) |
| Diazepam (Valium®) (reference) | 0-15 | 20-100 | 10 mg | 10 mg |
| Flurazepam (Dalmane®) | 0-15 | 47-100 | 30 mg | 20 mg (8 – 30 mg) |
| Lorazepam (Ativan®) | 15-30 | 10-20 | 1mg | 1.3 mg (1 – 4 mg) |
| Midazolam po (Versed®) | 0-15 | 1-4 | – | 7 mg (5 – 10 mg) |
| Oxazepam (Serax®) | 30-60 | 3-21 | 15 mg | 20 mg (5 – 40 mg) |
| Quazepam (Doral®) | 15-30 | 28-114 | 5 mg | 27 mg (15 – 40 mg) |
| Temazepam (Restoril®) | 30-60 | 10-20 | 30 mg | 20 mg (5 – 40 mg) |
| Triazolam (Halcion®) | 15-30 | 1.6-5.5 | 0.5mg | 0.25 mg (0.25 – 1 mg) |
*Half-life includes active metabolites and represents the time for the body to metabolize half the drug.
** Comparative Oral Dose: Equivalencies may vary across sources. This chart uses data from Ashton and ClinCalc, cross-referenced with additional sources [2,3,4,5].
*** Accumulates 23-fold over 2 weeks.
Decoding the Benzodiazepine Comparison Chart
This benzo strength chart provides a concise comparison based on several key pharmacokinetic parameters:
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Onset of Action: This column indicates how quickly you can expect to feel the effects of each benzodiazepine after oral administration. Medications with a faster onset of action, like diazepam and midazolam, can produce effects within minutes, while others such as oxazepam and temazepam may take longer.
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Half-life: The half-life is a crucial factor in determining how long a drug’s effects last and how frequently it needs to be dosed. It is the time it takes for the concentration of the drug in your body to reduce by half. Benzodiazepines exhibit a wide range of half-lives. Longer half-lives, such as those of clorazepate and flurazepam, mean the drug remains in the system for an extended period, potentially leading to accumulation with repeated doses and a longer duration of effect, but also potentially increasing the risk of next-day sedation. Shorter half-lives, like midazolam and triazolam, result in a quicker elimination from the body.
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Comparative Oral Dose: Due to variations in potency, a direct milligram-to-milligram comparison between benzodiazepines is not accurate. The “Comparative Oral Dose” columns, drawing from expert sources like the Ashton Manual and ClinCalc, offer an estimated equivalent dose relative to a standard reference, diazepam (Valium®), which is set at 10mg. It’s important to note that even within these sources, and across different clinical references, equivalencies can vary. This chart provides a range to highlight that variability. For example, alprazolam (Xanax®) and clonazepam (Klonopin®) are shown to be potent benzodiazepines, with much smaller comparative doses than diazepam.
Understanding Benzo Dosages and Potency
As highlighted in the chart, benzo dosages are not uniform, and the concept of a “low dose” is relative. A benzodiazepine strength chart like this is essential for understanding the varying potencies. For instance, according to Dr. Heather Ashton’s research, alprazolam (Xanax) can be significantly more potent than diazepam (Valium). The ClinCalc data also reflects this, showing Xanax to be considerably stronger than Valium. Similarly, clonazepam is often cited as having a high potency relative to other benzodiazepines.
It is also important to consider that the half-life values presented in the chart often include active metabolites. Many benzodiazepines are metabolized into other compounds that also possess benzo-like activity, contributing to the overall effect and duration of the medication. For a comprehensive list of benzodiazepines and their pharmacokinetic properties, further resources like the Wikipedia list of benzodiazepines can be consulted.
Disclaimer: This benzodiazepine strength chart is for informational purposes and should not be used for self-medication or dose adjustments. Always consult with a qualified healthcare professional for any medical decisions related to benzodiazepines.
