Opioid-induced pruritus: an update.

Pruritus is an unpleasant sensation leading to scratching. It can be a feature of numerous skin or systemic diseases, and may also be a side-effect of various drugs. Opioids are one of the best-known medicines evoking pruritus. The pathogenesis of opioid-induced pruritus is still not fully known, but two different mechanisms have been proposed: peripheral and central. Several treatment options have been tested for opioid-induced pruritus, but none has been completely satisfactory. Opioid antagonists seem to be the most potent antipruritic drugs, but they also decrease analgesia, which limits their usage. Many other treatments have been tried, but to date, the data are conflicting or only limited studies have been performed to confirm their efficacy. Further studies are still needed to better elucidate the mechanism of opioid-induced pruritus and to develop more effective treatment options.