The problem with using those so-called 'benzodiazepine equivilancy charts' is that they are written for the purposes of tapering
only, and assume chronic use of a given benzodiazepine, in exchange for chronic use of another benzodiazepine.
They are not
charts of how much therapeutic effect a single dose will have.
The long-acting benzodiazepines, because a daily dose results in a cumulative effect, will require a lower equipotent dose, all other things considered, than a short-acting benzodiazepine with no cumulative daily effect.
Therefore, the people looking to substitute, say, 1mg of alprazolam as a PRN dose for a panic attack, with, say, 1mg of clonazepam PRN, are apt to be very dissappointed. The alprazolam, once you take it, in 6 hours, 50% of it is gone, and 75% is gone after 12 hours. Basically, when you get out of bed in the morning after taken alprazolam the day before, there is *none* left in your system. The clonazepam (diazepam, flurazepam, chlordiazepoxide, etc.), if you take a pill a day, mathematically, will accumulate in the body to a dose level that is far
above the daily dose.
Doctors who understand accumulation and exponential decay properly understand this sort of stuff. A family doctor who just looks at an 'equivilancy chart', which is only
valid for the tapering of chronic use of the agent, will not.
The equivilancy charts are *not* wrong. But trying to use them to compare long-acting benzos to long-acting benzos in terms of therapeutic potency, is. Even Ashton points out that they are for tapering purposes only.
edit: oh my, did I just type out the same damn reply twice???? Geez, I'm getting bad at this
Edited by MarkP, 11 December 2009 - 03:29 PM.