Tapentadol. Acute or chronic pain: no therapeutic advance.

The standard opioids for relieving moderate to severe pain are: codeine as a step 2 analgesic and morphine for step 3. Tapentadol is an opioid similar to tramadol. An immediate-release form has been authorised in France for moderate to severe acute pain in adults and a sustained-release form for severe chronic pain in adults. It has been evaluated in comparative trials in several types of acute pain: pain following orthopaedic or gynaecological surgery or tooth extraction, and joint pain. These trials were principally designed to show its analgesic effect versus placebo.They did not establish the equianalgesic dose ratios of tapentadol to codeine, morphine or oxycodone. In chronic pain, one trial compared sustained-release tapentadol versus sustained-release morphine, but only unconvincing preliminary results are available.The results of other trials versus sustained-release oxycodone are unconvincing, because half of the patients were lost to follow-up. The known adverse effects of tapentadolare mainly those associated with all opioids, including neuropsychiatric disorders and addiction. Aggression and serotonin syndrome are possible reactions that require further investigation. Gastrointestinal disorders appeared less common with tapentadol than with oxycodone, but the data could well be biased due to the use of a relative overdose of oxycodone in the trials. In practice, the evaluation of tapentadol was not designed to show whether this drug represents a therapeutic advance. Its analgesic efficacy remains unclear, and it provokes the adverse effects common to all opioids.