No side effects from the Lidocaine patch. My primary physician prescribes them for me. I see a neurologist for the arthritis in my spine, but there was no reason the make a change. You can purchase them over the counter, but they are 3 or 4%, and the scripts is for 5%. They are expensive. I think I paid 40.00 co-pay for a 90 day supply (with insurance). You keep these on for 12 hours at a time. Hope all works out for you.