Tramadol
"I have been on this medication for about 4 years due to Ankylosing spondylitis and I find it pretty effective.  However, I have found that this medication caused unexpected side effects.  It was pointed out to me that shortly after taking a dose, I undertake massive projects that I normally wouldn't, become extremely talkative, insomnia and motivation that wasn't there originally.  I was diagnosed as being bipolar a year ago and these are all symptoms of the "hypermania" aspect of Bipolar disorder.  My doctor has found that Ultram put me in a "manic state" and when the medication begins to wear off I tend to become anxious and agitated.  There are studies reflecting this online. I would not recommend this medication if you are bipolar."