Lawrence K, Palmer G H, Needham J R
Res Vet Sci. 1986 May;40(3):413-5.
A preliminary investigation of the blood levels of carbenicillin, after the administration of a single intramuscular injection, suggests that the tortoise's bladder may act as a reservoir of antibiotic that is available for resorption. This phenomenon could confound the establishment of a safe, effective dose regime for antibiotics, in tortoises, which are excreted in an unchanged active form in urine.
