Which benzodiazepine has the longest half-life?

Which benzodiazepine has the longest half-life?

• A. Lorazepam - 10.5 to 12.9 hours
• B. Diazepam - 20 to 50 hours
• C. Alprazolam - 12 to 15 hours
• D. Triazolam - 2.3 hours

Answer: (B)

Half-life is a key factor in how long a benzodiazepine stays active in the body. Diazepam has long-lasting activity because, after it’s absorbed, it is metabolized into active metabolites (such as nordiazepam and others) that themselves have long half-lives. The combined effect of the parent drug plus these active metabolites results in a very long overall elimination time, typically cited around 20 to 50 hours. That extended elimination leads to a longer duration of action and a greater potential for accumulation with repeated dosing. The other drugs listed have shorter intrinsic half-lives and, in some cases, fewer long-lasting active metabolites, so their effects wane more quickly. Hence, diazepam has the longest half-life among these options.

Half-life is a key factor in how long a benzodiazepine stays active in the body. Diazepam has long-lasting activity because, after it’s absorbed, it is metabolized into active metabolites (such as nordiazepam and others) that themselves have long half-lives. The combined effect of the parent drug plus these active metabolites results in a very long overall elimination time, typically cited around 20 to 50 hours. That extended elimination leads to a longer duration of action and a greater potential for accumulation with repeated dosing. The other drugs listed have shorter intrinsic half-lives and, in some cases, fewer long-lasting active metabolites, so their effects wane more quickly. Hence, diazepam has the longest half-life among these options.