Evaluation of the effect of cephalexin and enrofloxacin on clinical laboratory measurements of urine glucose in dogs.
OBJECTIVE
To determine the effects of cephalexin and enrofloxacin on results of 4 commercially available urine glucose tests in dogs.


METHODS
6 healthy adult female dogs.


METHODS
In a crossover design, cephalexin (22 and 44 mg/kg [10 and 20 mg/lb], p.o., q 8 h) or enrofloxacin (5 and 10 mg/kg [2.3 and 4.5 mg/lb], p.o., q 12 h) was administered to dogs for 1 day. Urine samples were tested for glucose at 0, 6, and 24 hours after drug administration. In vitro, dextrose was added to pooled glucose-negative canine urine samples containing either no antimicrobial or known concentrations of either antimicrobial; urine samples were then tested for glucose.


RESULTS
In vivo, false-positive results were obtained by use of a tablet test in the presence of both antimicrobials and by use of a strip test in the presence of cephalexin. In vitro, false-positive results were obtained with the tablet test at the highest urine concentration of cephalexin (2,400 microg/mL) and with a strip test at the highest concentration of enrofloxacin (600 microg/mL). Enrofloxacin in urine samples containing dextrose caused the urine glucose tests to underestimate urine glucose concentration.


CONCLUSIONS
Cephalexin and enrofloxacin at dosages used in clinical practice may result in false-positive or false-negative urine glucose results, and care should be taken when using urine as a basis for identifying or monitoring diabetic animals.
Rees
Christine A
CA
Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4474, USA.
Boothe
Dawn M
DM
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000652:urine; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000652:urine; D002506:Cephalexin / Q000494:pharmacology* / Q000652:urine; D018592:Cross-Over Studies; D004283:Dog Diseases / Q000139:chemically induced / Q000175:diagnosis*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D000077422:Enrofloxacin; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology* / Q000652:urine; D005947:Glucose / Q000032:analysis*; D006029:Glycosuria / Q000139:chemically induced / Q000175:diagnosis / Q000662:veterinary*; D015363:Quinolones / Q000494:pharmacology* / Q000652:urine; D011897:Random Allocation
D000900:Anti-Bacterial Agents; D000970:Antineoplastic Agents; D024841:Fluoroquinolones; D015363:Quinolones; D000077422:Enrofloxacin; D005947:Glucose; D002506:Cephalexin