IM no doctor by anymeans but zoloft shouldnt reduce tramadols effectiveness it is more likely that your body is becoming accustom to the Tramadol. Try this it helps alot as I to have chronic pain. Take two max strength Tylenol (500MG) with the tramadol it helps and make it more effective. You can ask any doctor and they should agree with that. They don't know why it helps the effectiveness of Tramadol they just know that it Does.