This is why I've never discontinued the phentermine. I have sciatica, but I still exercise. It depends, tigger. Your doctor makes that call. Sciatica is nerve pain in the lower back.
People take beta-blockers, calcium channel blockers and all sorts of other drugs indefinitely.
If you have a chronic illness and you stop your medication your symptoms will come back. I walk, use the treadmill and lift weights mostly. I thought most obesity meds were intended for only a year's use. I stretch my back before I walk. Older medications like phentermine, diethylpropion, etc. were only tested for short periods of time.