Which of the following is not a side effect of Tramadol?

Excessive perspiration is not typically recognized as a common side effect of Tramadol. Tramadol is an opioid analgesic used to treat moderate pain and can cause various side effects, but the other options listed are more frequently reported. Nausea, confusion, and dry mouth are well-known side effects associated with Tramadol use. This indicates that while every medication can have a wide range of effects, excessive perspiration does not commonly occur as a result of Tramadol use, making it the correct choice in this context.