Hyperkalemia is a common side effect of these medications. GI disturbances, including nausea, vomiting, diarrhea, anorexia can occur. Triamterene and spironolactone have been known to cause impotence and sexual dysfunction. Spironolactone may precipitate gynecomastia or an SLE-like syndrome.
Flexeril has a half life of 18 hours. So 5x18 is 90 hours. Or just under 4 days. Of course, it is not that easy. This varies on how much and how long the drug was taken and it can vary from person to person. That being said I cannot image any way that flexeril would be detectable 30 days after the last dose.
It wasn't too hard to get off of. Skelaxin didn't work as well for me either but did work some as I felt it after I got of of it. For short term I would take Flexeril at night (5mg). Apparently Skelaxin doesn't work for you.Flexeril only works for 3 weeks then it is a sleeping pill really. I would go on an off as needed.