I have taken Nabumetone for 5 years at a dose of 500mg once a day when I have a lot of pain or every other day most of the time. Recently I had a bad flare up and was on Nabumetone 750 tablet once a day for 2 weeks. I noticed a swollen area on my lower lip about 15 min. after taking it just the other night. I took Benadryl (2 capsules) immediately to counteract a possible allergic reaction. Am I over reacting? I have never had any hives or swelling before. My pain is down considerably but I have stopped the Nabumetone out of fear. Any advice? I may see my doctor very soon.