Posted by Squiggles on February 6, 2007, at 21:31:15
In reply to Re: Benzo Confidential - clonazepam's history, posted by Squiggles on February 6, 2007, at 21:11:45
From a presentation article by Professor Heather Ashton, I see a proposed explanation for the particular difficulty of withdrawing from Clonazepam to be the unappreciated potency of
the drug (along with some others):----------------------------------------------
History of Benz odiazepines: What the Textbooks May Not Tell You
(3rd Annual Benz odiazepine Conference, Bangor, Maine, October 12, 2005)
C.H. Ashton" [SLIDE 10 ] Half-lives and equivalent potencies of benz odiazepine
anxiolytics
Explain slide (elimination half-lives and approximate clinical potency of some
benzodiazepines compared to diazepam). The three most potent in this group of anxiolytics
are alprazolam, clonazepam and lorazepam which are 10-20 times more potent than
diazepam. This difference is often disregarded and the drugs prescribed in excessive dosage.
For example, I have recently seen patients prescribed alprazolam in daily doses of 4-6mg
equivalent to 80-120mg of diazepam. Alprazolam is no longer prescribed under the NHS in
the UK though it can be prescribed privately. I have also recently seen lorazepam prescribed
in 6, 10, and over 12mg daily doses again in equivalence up to 120mg diazepam. Both
these drugs are fairly short-acting and have to be taken 3-4 times a day. Patients often suffer
mini-withdrawal symptoms between doses. Clonazepam is also very potent, 10-20 times the
strength of diazepam. In the UK it is only officially indicated as an anticonvulsant for
epilepsy but it is popular in the US and British doctors are following suit and prescribing it for
anxiety.
All these three drugs are highly addictive; dependence develops rapidly and they are
particularly hard to withdraw from. This difficulty is partly due to the relatively excessive
dosage used, partly I suspect from their potency which probably means that they bind
particularly avidly to GABA/BZ receptors, partly because equivalent potencies are not
adhered to when switching patients to other benzodiazepines such as Valium or Librium in
attempts at withdrawal, and partly because they are not available in small enough dosage
strengths to allow for gradual dosage reduction. In the UK Ativan is only available in 2.5mg
or 1mg tablets. The 1mg tablet is equivalent to 10mg diazepam. Even if you halve it you are
withdrawing by decrements of 5mg in diazepam equivalents, which can be a big drop for
some people. Strangely, 0.5mg Ativan tablets are available in the US and Canada, but all
attempts to get the drug company (Wyeth) to supply this in the UK have failed. "pdf file: (xpdf:/tmp/Maine.benzo2.pdf)
-----------------------------------------
However, in my experience, alprazolam (XANAX) was a piece of cake to withdraw from (1.50mg over about 7-10 yrs.) in comparison to clonazepam (1.0mg) over about the same time.
Squiggles
poster:Squiggles
thread:730516
URL: http://www.dr-bob.org/babble/20070201/msgs/730622.html