Tramadol is a synthetic opioid that acts via opioid receptors and serotoninergic and noradrenergic pathways to produce analgesia.
It is as effective as some established opioids in some indications, but is less effective than morphine in severe pain and is not suitable as the analgesic component of balanced anaesthesia.
However, it does appear to carry a low risk of respiratory depression and opioid addiction.
Whether this represents a clinically significant reduction in risk when compared with other opioids used in properly titrated dosages has not been established.
The reduced risk of constipation may be the major advantage of tramadol over other opioids, such as codeine, in the treatment of mild or moderate pain.