Comparison of the effects of etomidate and its fluoro analogue, R 8110, on plasma cortisol, 11 beta-deoxycortisol, 17 alpha-hydroxyprogesterone and testosterone concentrations in dogs.
R 8110, an imidazole derivative, was shown to be clinically superior to etomidate for induction and maintenance of anaesthesia in dogs. The present study compared the effects of intravenous (i.v.) R 8110, etomidate and Ringer solution on cortisol biosynthesis by the adrenal gland in seven male labradors. A tetracosactide challenge was carried out 30 min after the i.v. injection of 3 mg/kg of both drugs and after i.v. Ringer solution (1 ml/kg). Etomidate and R 8110 both suppressed the cortisol response to tetracosactide almost completely and increased the plasma 11 beta-deoxycortisol levels more than 20 fold. Maximal 11 beta-deoxycortisol values were reached 120 min after R 8110, and not less than 300 min after etomidate. Plasma 17 alpha-hydroxyprogesterone and testosterone concentrations did not differ between placebo and R 8110 treatment, but they decreased after etomidate. These results indicate that the effects of R 8110 on steroid biosynthesis in dogs are less pronounced than those of etomidate and are largely limited to a temporary inhibition of the 11 beta-hydroxylase in the adrenal gland.
De Coster
R
R
Janssen Pharmaceutica, Beerse, Belgium.
Degryse
A D
AD
Van Dijk
P
P
Ooms
L A
LA
Lagerweij
E
E
D015065:17-Hydroxycorticosteroids / Q000097:blood*; D000818:Animals; D003350:Cortodoxone / Q000097:blood*; D004285:Dogs / Q000097:blood*; D005045:Etomidate / Q000031:analogs & derivatives* / Q000494:pharmacology*; D006854:Hydrocortisone / Q000097:blood*; D006908:Hydroxyprogesterones / Q000097:blood*; D008297:Male; D013739:Testosterone / Q000097:blood*
D015065:17-Hydroxycorticosteroids; D006908:Hydroxyprogesterones; C052803:R 8110; D013739:Testosterone; D003350:Cortodoxone; D006854:Hydrocortisone; D005045:Etomidate