New opioids.

Despite the skilled use of opioid analgesics, which is crucial to the relief of cancer pain, there is a lack of evidence to support many aspects of current clinical practice. Therefore, there is a significant need for more effective treatment options. New opioids have been marketed in the past years, including hydrocodone and oxymorphone. Moreover, mixed opioids with combined mechanisms of action have been developed; one such agent, tapentadol, is a centrally acting oral analgesic that possesses a combined mechanism of action: μ-opioid receptor activation with norepinephrine reuptake inhibition. Drug development strategies involving naloxone have been initiated to reduce peripheral opioid-related adverse effects. The rationale is based on the local antagonist activity of naloxone in intestinal opioid receptors and the negligible oral bioavailability of naloxone, particularly in a prolonged-release formulation. New delivery systems have been developed to provide rapid analgesia with potent opioid drugs such as fentanyl. Despite the upcoming availability of these new drugs and technologies that will add to existing types of opioid medication, their benefits and liabilities will ultimately need to be determined by the individual physician and individual patient experiencing pain.