I take 20 mg in the mornings and i usually feel relief in 20-40 minutes from the op 40s. Today its been 3 hours and i took 40 mg because my back was hurting more than usual this morning. Would anyone know why i would be taking SO long to feel relief. This has happened once or twice before but i do not remember what triggered it to start to work. Is there a possibility its not going to work and i should take more? Please some help im in pain!! thanks