Basic Vetoryl Monitor

ACTH Stimulation and Na:K ratio

In order to monitor Vetoryl® it is important to know what effect the medication is having on adrenal function. The test is performed 4-6 hours after the medication when Trilostane is at its greatest level of activity. By sampling at this time we know what the greatest level of adrenal suppression will be. It is likely that later in the day, suppression will be less. There are circumstances when investigating problem cases, that it may be appropriate to perform the ACTH stimulation test outside this period on the guidance of a specialist or Dechra Technical Support (01939 211200).

Vetoryl® will inhibit both glucocorticoid and mineralocorticoid production. Sodium and potassium are included because they will help identify whether there is too much suppression of the adrenal glands.

In interpreting the ACTH stimulation test 4-6 hours post Vetoryl® Capsule, we are looking for evidence of suppressed steroidogenesis, that is, post-ACTH cortisol concentrations <250nmol/L that also show an increase over baseline levels. The failure of ACTH to stimulate an increase in cortisol concentrations suggests that consideration be given to lowering the dose or withholding medication. Please note all the following diagnostic and treatment flowcharts are reproduced by kind permission of Dechra Veterinary Products.