Q: I am 59 years of age having had Addison's Disease for four years and taking 15mg hydrocortisone at 08.00 hours, 10mg hydrocortisone at 12.00 midday and 2.5mg prednisolone at 16.00 hours I am going to Australia in late December and for most of January, as it will be very hot and humid at this time of year I would value your advice on precautions that I would take for this holiday.

A: I cannot comment on the regimen using a mixture of hydrocortisone and prednisolone as I am not familiar with this. Certainly the first morning dose should be taken before the patient gets out of bed immediately on waking and on an empty stomach. If a patient has adequately replaced the fludrocortisone then there should be no need to alter the dose in hot and humid climates. Certainly there is no need to change the hydrocortisone dosage. The dose of fludrocortisone would be a very small dose for an adult with Addison's Disease. Before going to Australia it would be worth checking with the endocrinologist that adequate tests have been taken to make sure that this is an adequate dose of this "mineralocorticoid". Adequacy of fludrocortisone replacement is usually determined by measuring levels of the hormone renin.