Can tramadol cause difficulty urinating? I am on 100mg for my knee. Even with a full bladder I have to work really hard to get urine out.

Tramadol. Tramadol (Ultram) is a rather unique analgesic drug that is indicated for moderate to moderately severe pain. Although it binds to mu receptors, tramadol is not technically classified as an opioid analgesic. Like any other medication Tramadol has some serious side effects. Very rare tramadol can induce urinary problems such as a difficulty to urinate, painful urination or urinary retention.