I would like to "piggyback" on to the statement above by saying that you should have a long talk with the anesthesiologist first before you attempt anything. They can tell you if they can change the "cocktail" of meds during surgery to compensate for the methadone in your system. Here is the problem you need to think about: Compared to other opioids, methadone has the potential to stay in your system for a long time. In fact, the elimination half-life of methadone is anywhere from 8 to 59 hours.
"Half-life" refers to the time it takes for the blood levels of methadone to be reduced by half. This means that every 8 to 59 hours, the level of medication in your blood will drop by 50 percent of the previous level.
With such a wide range of a reported elimination half-life for methadone, it is impossible to say exactly how long the medicine will stay in the body for any particular person. In addition, methadone accumulates in the liver and other tissues, where it is released slowly. This means that it could potentially stay in the system for a long time.
Best of luck!
One other comment I forgot to say - in addition to your doctor/surgeon - make sure that the anesthesiologist is aware that you've been on methadone, whether you are completely off of it prior to surgery day or not - just in case any anesthesia plans have to be adjusted/changed.
I totally agree that you need to discuss a tapering schedule with your doctor/surgeon for the methadone. Methadone has a long half life, so it does take a good while for it to be completely removed from your body - therefore, it'll be important that the taper be started far enough in advance of your surgery to allow for enough time for a proper taper according to your doctor's instructions, as well as time for the methadone to be completely eliminated from your body prior to surgery. If at all possible, allow for a little extra time in case you have any difficulties with the taper schedule that your doctor sets and need to make some adjustments (of course, again, with your doctor's instructions).
Whether you're on the methadone for pain management or addiction issues - it doesn't matter - you'll also need to make sure that the reason you're on it currently is addressed during and after surgery. If you're taking it for pain management, this might mean that you require a stronger pain med following surgery than someone who is not already opoid tolerant. And if you're taking it for addiction issues, you'll want to work very closely with your doctor/surgeon and follow all their instructions regarding medications to help avoid any problems with potential addiction troubles.
By all means, discuss this in length with your docttor/surgeon at length to make sure that you both are comfortable with not only the taper schedule he/she sets, but also with how pain control, etc., will be handled following surgery.
Best of luck!
This should definitely be addressed ONLY by a physician and not someone on a website. Methadone is a medication that SHOULD be titrated down per a qualified medical physician recommendations not recommendations per a website. There is per se no "cookie cutter" titration algorithm. It will depend on dosage, why it was prescribed, etc.
It is best to wait for his recommendations since he will be doing the surgery and KNOWS your medical background, what medications will be used for the surgery, etc.