Sf. Foster et al., Effect of phenobarbitone on the low-dose dexamethasone suppression test and the urinary corticoid: creatinine ratio in dogs, AUST VET J, 78(1), 2000, pp. 19-23
Objectives To investigate potential effects of phenobarbitone on the low-do
se dexamethasone suppression (LDDS) test and urinary corticoid to creatinin
e ratio in dogs in a controlled prospective study and in a clinical setting
.
Animals Ten crossbreed experimental dogs and 10 client-owned dogs of mixed
breeds treated chronically with phenobarbitone to control seizures.
Procedures Experimental dogs were allocated to treatment (6 mg/kg oral phen
obarbitone, n = 6) and control (n = 4) groups. LDDS tests (dexamethasone 0.
01 mg/kg intravenously, cortisol concentration determined at 0, 2, 4, 6 and
8 h) were conducted repeatedly over a 3-month period. Urinary corticoid to
creatinine ratios were measured before LDDS tests. A single LDDS test was
performed on 10 epileptic dogs.
Results LDDS and urinary corticoid to creatinine ratios in dogs were not af
fected by treatment with phenobarbitone.
Conclusions Phenobarbitone does not interfere with LDDS testing regardless
of dosage or treatment time. Urinary corticoid to creatinine ratios are als
o unaffected.