Patients with tuberculous Addison's disease usually require antituberculous chemotherapy. It is important to recognise the problems that may ensue if rifampicin is used. The enzyme induction that is produced increases the metabolic clearance of cortisol and thus may precipitate an adrenal crisis. Higher-than- usual doses of replacement therapy are therefore required in patients on rifampicin, and also those on anticonvulsants (which induce the same enzymes). Measurement of plasma renin levels assists in tailoring the doses of 9a-fludrocortisone to suit the needs of individual patients.
