[Opioids and new trends in pain therapy]

Opioids are well known for their ability to reduce the perception of pain without a loss of consciousness. However, the influence of opioids on organism is very complex. Clinical pharmacology of currently available opioid analgesics is determined by three major factors - their opioid receptor properties, pharmacokinetic properties and genetic polymorphism in the opiate receptor and cytochrome P450 isoform. In acute severe pain are opioids very efficient. Long-term experience with opioid analgesia in patients with cancer pain has shown high favorable risk/benefit ratio. However, the treatment with opioids has its issues. Life expectancy of chronic pain patients is temporarily unlimited and for that reason the time horizon of opioid therapy is unlimited as well. In comparison with cancer pain opioid responsiveness to chronic non-cancer pain is somewhat different. Clinical experience has shown that exceeding of medium-sized doses of opioids in the treatment of chronic non-cancer pain does not lead to further improvement of analgesia, but only increases degree of physical dependency and tolerance. The most important step is to choose the right patient. Subsequently, the success of opioid therapy depends on a careful search of balance between pain, opioid dosage and analgesia with emphasis on individualization and attention to the prevention and management of side effects.