Chronic pain--challenge and response.

Tramadol is effective in treating both acute and chronic pain, exhibiting a potency equivalent to that of pethidine, and it has an acceptable adverse event profile. Whilst the most common adverse events are nausea, vomiting, drowsiness and dizziness, as would be expected from an opioid, there is a noticeable lack of respiratory depression. This latter property, together with its low potential for the development of tolerance and dependence, make tramadol a most interesting agent for clinical use. The studies reported in this article illustrate the beneficial and adverse effects of tramadol to enable the clinician to judge the value of this agent.