Posted by Quintal on February 14, 2007, at 20:07:31
In reply to Re: Is Xanax the most potent benzodiapine in the U, posted by valene on February 14, 2007, at 17:59:51
Here are some quotes by Ashton herself that may help explain what you've observed;
__________________________________________________First you may ask how these equivalents were arrived at. Most were determined by direct clinical titration. In about 1983 Professor Michael Rawlins and I in Newcastle titrated the dose of diazepam required to substitute, in terms of anxiety symptoms, in 20 anxious patients on various doses of lorazepam. The mean came to an equivalence of 9.8mg diazepam for 1mg lorazepam. This is close to the equivalence of 1:10mg now officially accepted in most texts. Similar clinical tests were conducted for other benzodiazepine such as alprazolam though some equivalents are based on clinical experience during withdrawal of patients on various benzodiazepines who were switched to diazepam. Some equivalents were derived from animal work and human trials by drug companies. There is now a general consensus, at least in the UK, about equivalent potencies for both anxiolytic and hypnotic benzodiazepines. They are quoted in the British National Formulary produced by the British Medical Association and the Royal Pharmaceutical Society circulated to all doctors and in many published papers. Unfortunately, not all doctors read or heed this advice!
All these equivalencies are of course approximate. There is considerable individual variation in how people react to benzodiazepines. In addition, there are subtle differences in the pharmacological profiles of different drugs, and the equivalences do not always work at higher doses. For example, in my clinical experience diazepam is rather more sedative than lorazepam (Ativan) which is more anxiolytic. So if you abruptly change someone on say 6mg Ativan to 60mg of diazepam, he is likely to become very sleepy but may still be anxious. However, you can accomplish a changeover if you do it gradually and stepwise, dose by dose, titrating each dose to the clinical response. People also have differences in the speed at which they metabolise drugs, but on the whole the equivalences apply generally, except possibly in the case of benzodiazepines which have active metabolites such as diazepam where the half-lives of these can vary from 36-200 hrs.
http://www.psychmedaware.org/History%20of%20Benzodiazepines.html
__________________________________________________Q
poster:Quintal
thread:732765
URL: http://www.dr-bob.org/babble/20070213/msgs/732890.html