In my experience klonopin and xanax are about the same mg for mg, but klonopin never worked nearly as good as xanax did. I actually found that xanax xr worked the best for anxiety without having any signifigant side effects like drowsiness. So what is the reason that your doc wants to switch your meds up? Are you planning on quitting the benzos or just not getting the relief you need? I was taking benzos for about 4-5yrs on and off, I tried basicly everyone of the main ones. I personally never had too hard of a time coming off of them for some odd reason, besides it messed with my sleep. Obviously when you do switch you should really try and get by with the least amount possible and not worry so much about what exactly is the equivalent dose. The key is what works the best for you and finding that lowest effective dose. Im sure you know but I have to add that somewhere over 90% of methadone related overdoses are due to mixing benzo's in, so be really careful. I know you've been taking them both for a long time so Im not gonna preach about it, but just be aware and stick to the lowest effective dose. Im not sure if any of this helps, I was on methadone for years, along with benzos and various other opiates, it took me a long time to make it out. Anyways I hope everything goes well, good luck and take care.
Shrinks generally hate benzos. They have a point -- they're addictive, and after long-term use, can be tricky to wean from. Most handbooks recommend them for two weeks, maximum, including taper.
You've done your own research, which is always wise. Punch "benzodiazepines conversion" into a search engine, and go with the U.K. site, where you'll find tapering info as well.
I can tell you that Klonopin (a.k.a. Rivotril; generic name clonazepam) is 10x the strength of Valium, so 1mg K = 10mg V. No shrink (or GP, for that matter, although there are exceptions) is going to be comfortable with a patient taking the equivalent of 30-40mg of Valium a day, but he's inherited a case where that's your dosage.
I think he's going to go with something like this: Hold you at 3mg K, with an eye to a long taper (both K and V are used to get people off the shorter-acting benzos, so expect -- demand, if necessary- to stay on K at the present dose. He can't just pull the plug; the seizure risk is too high, so don't worry about it. There's a decent chance you can argue for a bait-and-switch: taper off the Xanax while holding the K at the present dose. When you're off the X, he'll probably want to reduce the K slowly. Bring printouts from the site if necessary, expressing your concern about moving too fast. This is all in his Desk Manual.
I have experience with taking long-term benzos (still am) from a GP. Addiction Specialists and shrinks are appalled, but since they help me (even though my resistance to these drugs is phenomenal) with insomnia, they shrug and say, "You're going to have a hard time coming off them, if you even can."
They're right. For people who have the time and money, it starts with a 28-day in-house rehab, with a gradual switch to Imovane (which is so similar to benzos, it's just a technicality to separate them) or phenobarbital. Sleep disruptions can persist for a long time, but who wants to be chained to doctors and drugs forever?
Don't worry, though -- it would be clear-cut malpractice to cut you off entirely. Good luck and let us know how it goes.