[Co-analgesics in the treatment of chronic pain]

Opioids do not yield adequate analgesic effects in at least one-third of all patients suffering from chronic pain. Nonetheless, in contrast to former opinion there is no type of pain that is principally resistant to opioids, which means that the individual patient's response to opioid administration has to be investigated to determine adequate treatment. Opioids fail most frequently in cases of neuropathic, osseous or sympathetically maintained pain. In these cases there is an indication for early use of co-analgesics. The analgesic potency of anticonvulsives and tricyclic antidepressants has been best documented. A differential indication of the large number of possible coanalgesics should be determined with the help of a detailed pain history focussing on the pain quality. Similar to the WHO analgesic ladder used in (tumor) pain therapy, co-analgesic therapy should only be supplemented by invasive therapeutic procedures after various combinations and alternative substances have proven fruitless. Experience shows that this is necessary only for a small number of patients.