Glucocorticoid maintenance therapy following adrenalectomy: assessment of dosage and preparation

Plasma cortisol was monitored repeatedly after oral administration of cortisol and cortisone (cortisone acetate) to seven adrenalectomized patients with pituitary-dependent Cushing's syndrome. The amount of glucocorticoid administered was 25 mg cortisol or 33 mg cortisone/g urine creatinine/24 h. Peak plasma cortisol levels were within recommended values in all patients after cortisone and in three of the patients after cortisol. The remaining four patients had elevated peak plasma cortisol levels after cortisol. Transcortin binding capacity in plasma was normal. It is concluded that cortisol as well as cortisone is suitable for oral glucocorticoid substitution therapy in patients with normal liver function, but that cortisone apparently gives a marginally smoother plasma cortisol curve. However, it is essential to monitor plasma cortisol after institution of glucocorticoid maintenance therapy, since different and unpredictable plasma cortisol levels may exist after a given amount of glucocorticoid, although the dose required correlates reasonably well with creatinine excretion in urine.