Thanks for all this info. Took one 500mg pill at 4pm today,had severe pain in right lower leg about 4 hours later.Thought it was varicose vein problem,even though the pain was differrent.I will never again get a prescription filled unless i look it up on the net first.Usually i do not even take any meds, but i was so sick( or so i thought ). The side effects can be worse than the problem. Thanks to this site and all you who told your stories, may you all find some relieve, you saved me and many others i am sure.