Benzodiazepines, commonly referred to as benzos, are a class of psychoactive drugs with varied pharmacological properties. For healthcare professionals and individuals seeking to understand these medications, comparing their characteristics is crucial. This Benzo Comparison Chart provides a concise overview of key attributes, including 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.com |
|---|---|---|---|---|
| Alprazolam (Xanax®) | 15-30 | 6-20 | 0.5 mg | 0.75 mg (0.5 – 2 mg) |
| Bromazepam (Lexotan®, others) | 15-30 | 8-30 | 3 mg | – |
| Chlordiazepoxide (Librium®, Limbitrol®) | 15-30 | 5-100 | 10 mg | 33 mg (12 – 50 mg) |
| Clobazam (Onfi®)*** | 20-30 | 42-47 | 20 mg | – |
| Clonazepam (Klonopin®, Rivotril®) | 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®, Loreev®) | 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 is the time it takes for your body to metabolize half of the drug, and includes active metabolites (e.g., oxazepam is a metabolite of diazepam).
** Comparative Oral Dose: Since there is no standard, equivalencies vary between the sources. This table was compiled from the two sources shown in the table, and was checked against four others.[2,3,4,5]
*** Accumulates 23-fold over 2 weeks
This benzo comparison chart highlights the variability among benzodiazepines. The ‘Onset of Action’ column indicates how quickly you might feel the drug’s effects after administration. As shown, most listed benzodiazepines have a rapid onset of action, typically within 15 to 30 minutes, while some like Diazepam and Midazolam can act even faster. Oxazepam and Temazepam, on the other hand, tend to have a slower onset, taking 30 to 60 minutes to become fully effective.
‘Half-life’ is a crucial pharmacokinetic parameter, representing the time it takes for the concentration of a drug in the body to reduce by half. Benzodiazepines exhibit a wide range of half-lives. Some, like Midazolam and Triazolam, are short-acting, while others, such as Chlordiazepoxide, Clorazepate, and Flurazepam, are long-acting, with half-lives potentially exceeding 100 hours due to active metabolites. It’s important to note that the half-life includes active metabolites, which can prolong the overall effects of certain benzodiazepines. For instance, Diazepam metabolizes into active compounds, contributing to its extended duration of action.
The ‘Comparative Oral Dose’ columns provide a crucial perspective on benzodiazepine potency. Because there isn’t a universally agreed-upon standard for benzodiazepine equivalency, this chart presents comparative doses from two reputable sources: Professor Ashton’s data and ClinCalc.com. These comparisons illustrate that the strength of benzodiazepines varies significantly. For example, Alprazolam (Xanax) and Clonazepam (Klonopin) are potent benzodiazepines, with much smaller comparative doses than Diazepam (Valium), which is used as a reference point.
It’s evident from this benzo comparison chart that understanding comparative dosages is essential. Terms like “low dose” or “high dose” are relative and depend heavily on the specific benzodiazepine. For example, Ashton’s data suggests Xanax is 20 times more potent than Valium, while ClinCalc indicates a range of 5-20 times stronger. Similarly, Clonazepam’s potency compared to Temazepam varies significantly between sources, highlighting the importance of consulting reliable comparative dose charts when considering benzodiazepine usage.
For a more comprehensive list of benzodiazepines and their pharmacokinetic properties, refer to this List of Benzodiazepines on Wikipedia. This benzo comparison chart serves as an initial guide to understanding the variations in onset, duration, and potency among common benzodiazepines. Always consult with healthcare professionals for personalized medical advice and dosage information.
