Is 20 mg of Flexeril a common dose 3xday?

Hi, Finocchi!
This is from information here on Drugs,com:
"For most patients, the recommended dose of FLEXERIL is 5 mg three times a day. Based on individual patient response, the dose may be increased to 10 mg three times a day. Use of FLEXERIL for periods longer than two or three weeks is not recommended."

Lots of things determine how you will respond to any particular drug, the largest factor ( that you have no control over) is your genetics. Some people are genetic non-responders to certain drugs. For instance, I can't respond to naltrexone. As 10 mg 3x a day really is a larger dose regimen, I am suspecting you just don't respond to it and increasing the dose will just buy you more side effects and little relief. I am a chronic pain patient, in addition to being a pain doc. Over the years I have found that I respond really well to some muscle relaxers and not at all to others. At this point, I'd ask your doctor to switch you over to a different relaxer.