Mobic (brand name) is an alternative to diclofenac. I know this because when I told my Spine Dr at my last visit that I could only take the diclofenac once a day or it upset my stomach, he said let's try this instead.
He scripted me 15mg of Mobic a day.
But I would get your grandmother into see a doctor. These are both VERY strong anti-inflammatories which have hordes of horrible side effects. I am not sure if Mobic would be a good choice for her as I do not know what other meds she is on. Anyway, it would be an option to mention to her doctor.
“We are what we imagine ourselves to be. ” ― Kurt Vonnegut