Our primary outcome is to determine whether AZD4017, an inhibitor of 11β-HSD1, will reduce the pressure in the brain and as a consequence improve IIH. Patients are eligible to enter the study if they are between 18-55 years old with acute (<6 months) IIH, signs of active disease (papilloedema and raised CSF pressure (>25 cmH20)), no other major illnesses and have no plans for pregnancy during the study period.