There is provided a pharmaceutical composition comprising (i) a compound of the formula ##STR00001## wherein: X is a hydrocarbyl ring having at least 4 atoms in the ring; K is a hydrocarbyl group; Rs is a sulphamate group; (ii) optionally admixed with a pharmaceutically acceptable carrier, diluent, excipient or adjuvant, wherein the compound is present in an amount to provide a dosage of no greater than 200 .mu.g/day.