Is Vimovo Safe And Effective In Treatment Of Back And Leg Pain?

Hi, I have been prescribed Vimovo 500/20 mg to be taken h.s for severe leg cramps emanating from back problems. The prescribed dosage is not holding the leg cramps at bay for the entire night. Can I safely increase the dosage, or should I go back to taking 800 mg ibuprofen (which does work) until my GP returns from vacation?