How long does it take for 10 mg flexeril to start working? And how long will it work for?

I have taken 3 today and no relief for me at all.

I don't know because for me it don't work well by itself. It only works with my other medicines.

I notice it helps relax me and reduce pain in about 30-40 minutes. I'm not sure how long the half life is..should be easy enough to find in a search.

I took a mine tonight only took about 15-20 mins to kick in

I find it works right away, 20-30 minutes and I get a good 6 hours out of it. Makes me very groggy though.

Fexeril is a muscle relaxer & my doc prescribes it twice a day, but it doesn't always last that long. My hubby takes it too, & he can take it every 6 hours if needed. It usualyy takes a good 20 to 30 minutes to get going in your system where your muscles spasms will relax a bit, also put a heating pad where you are having th spasms. Pleas read the link below...
https://www.drugs.com/flexeril.html