Safety and Efficacy of Prednisolone in Adrenal Insufficiency Disease (PRED-AID Study)

Inclusion Criteria:

• Aged 18 - 70 years
• Male or female
• Diagnosed with AI for over 6 months according to standard diagnostic criteria
• Established on stable HC replacement or prednisolone replacement, dose not altered forat least 3 months
• Established on a stable dose of Fludrocortisone, if taking, dose not altered for atleast 3 months
• Participants taking other hormone replacements (e.g. levothyroxine, testosterone orgrowth hormone in secondary adrenal insufficiency) are accepted providing that theirreplacement doses have not altered for at least 3 months
• Participants who are otherwise healthy enough to participate, as determined bypre-study medical history and physical examination.
• Participants who are able and willing to give written informed consent to participatein the study.

Exclusion Criteria:

• Participants with a diagnosis of Type 1 or Type 2 diabetes mellitus.
• Unable to give informed consent.
• Taking supplements or herbal medications that the participant is unwilling or unableto stop prior to and during the study period e.g. St John's Wort (may decreaseprednisolone levels), Cat's claw, Echinacea (immunomodulatory properties).
• Currently taking medications that alter CYP3A4 metabolism of glucocorticoids that theparticipant is unwilling or unable to stop prior to and during the study period e.g.phenytoin, phenobarbital, rifampicin, rifabutin, carbamazepine, primidone,aminoglutethimide, itraconazole, ketoconazole, ciclosporin or ritonavir.
• Pregnancy, taking the combined oral contraceptive pill, or oral oestrogen replacementtherapy due to the effects on cortisol binding globulin levels and determination ofprednisolone levels. Transdermal oestrogen replacement is permitted.
• Diagnosis of congenital adrenal hyperplasia, untreated