"we&#039;ll i have been on this medication for 7 months now. at first it worked well for my pain. your body has to get used to it . this medication works well for my joint pain in back and knees. it will work for headache also. but these past 2 months i&#039;ve had terrible side effects. i get these stomach pains from hell. i get sick and throw up.  the stomach pain is unbearable . taking the 18mg. 3xs a day sometimes only able to take 1 a day with food for sure and the stomach pain will come. also has caused upper respiratory infection 2xs now."