The use of a compound comprising formula (I), or a salt, ester, amide or prodrug thereof in the treatment of obesity and related disorders. The invention also relates to novel compounds within formula (I), to processes for preparing them and pharmaceutical compositions containing them. In formula (I): A is an optionally substituted thienyl moiety, Y is O, S, or NR.sup.2, R.sup.1 is a branched or unbranched alkyl (optionally interrupted by one or more oxygen atoms), alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, reduced arylalkyl, arylalkenyl, heteroaryl, heteroarylalkyl, heteroarylalkenyl, reduced aryl, reduced heteroaryl, reduced heteroarylalkyl or a substituted derivative of any of the foregoing groups and R.sup.2 is hydrogen or a group as defined for R.sup.1. ##STR00001##