What is biofenac? Is it addictive? Does it have a narcotic in it? What are possible side effects? I am 55 with a swollen meniscus cartilege, probably from increasing running too fast. I weigh 150 and am 5 ft four inches. I have had no other knee problems and no significant medical history. I do have low thyroid treated with synthroid. I got a dog and increased my running from three times per week, five miles per run to an extra one or two slow miles a day with the dog (stop and go). Have rested three weeks; still swollen. MD friend from another country recommended this medicine (biofenac) and said take one time per day after full meal at dinner.