Compounds for use in the treatment or prophylaxis of pain, including acute and chronic pain (e.g., nociceptive pain, neuropathic pain, headaches, migraine), represented by general formula (I) in which: the dotted line represents a single or a double bond； and R5 and R5&prime； are independently &mdash；H, &mdash；OH or &mdash；OR6, where R6 is a linear or branched C1-C4 alkyl； X is -0-, &mdash；CH2O&mdash；, &mdash；CH2CH2O&mdash；, &mdash；CH(CH3)CH2O&mdash； or &mdash；CH2CH(CH3)O&mdash；； Z is &mdash；CH2CH2O&mdash；, &mdash；CH(CH3)CH2O&mdash； or &mdash；CH2CH(CH3)O&mdash；； m is an integer of O or 1； and n is an integer of 0-50. The compounds of the invention are also effective for reducing inflammation and may be used alone or in combination with other analgesics.
