The present invention relates to compounds of formula (I), wherein R is C1-6alkyl, C2-6alkenyl, C2-6alkynyl, C3-7cycloalkyl, C3-7cycloalyklC1-4alkyl, which groups are optionally substituted by hydroxy, C1-4alkoxy or NRaRb, where R?a and Rb¿ each independently represent hydrogen or C¿1-4?alkyl; or R is C1-4alkyl substituted by Ar, and optionally further substituted by one or both of R?4 and R5; R1, R2 and R3¿ represent a variety of substituents; R?9 and R10¿ are each hydrogen, halogen, C¿1-6?alkyl, CH2OR?e¿, oxo, CO¿2R?a or CONRaRb where Re represents hydrogen, C¿1-6?alkyl or phenyl; X is -CH2, or -CH2CH2-; Y is -CH=, -CH2-, -CH2CH= or -CH2CH2-, with the proviso that the sum total of carbon atoms in X+Y is 2 or 3; and when Y is -CH= or -CH2CH=, the broken line is a double bond; or a pharmaceutically acceptable salt thereof. The compounds are of particular use in the treatment or prevention of pain, inflammation, migraine, emesis and postherpetic neuralgia.