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' are independently -H, -OH or -OR6, where R6 is a linear or branched C1-C4 alkyl； X is -CH2O-,； Z is -CH2CH2O-CH(CH3)CH2O- or -CH2CH(CH3)O-； m is 1； and n is an integer of 1- 5. The compounds of the invention are also effective for reducing inflammation and may be used alone or in combination with other analgesics.
