Effect of trimethoprim/sulfamethoxazole on thyroid function in dogs with pyoderma.
The effect of trimethoprim/sulfamethoxazole (T/SMX, 30 mg/kg, PO, q 12 h for 6 weeks) on thyroid function was evaluated in 21 dogs with pyoderma and normal baseline serum thyroxine concentrations. The population mean serum thyroxine concentration, but not the population mean serum triiodothyronine concentration, was significantly decreased at the end of treatment. After 6 weeks of treatment, the response in 3 dogs to thyrotropin administration was substantially reduced. Radionuclide thyroid imaging of 2 dogs after T/SMX treatment revealed higher-than-normal thyroid technetium 99m pertechnetate uptake, suggestive of an interference with iodide metabolism. Use of T/SMX may cause hypothyroidism, and inadequate thyroid function may be incorrectly diagnosed in dogs treated with this antimicrobial.
Hall
I A
IA
Department of Veterinary Clinical Medicine, University of Illinois, Urbana 61801.
Campbell
K L
KL
Chambers
M D
MD
Davis
C N
CN
D000818:Animals; D001947:Breeding; D004283:Dog Diseases / Q000139:chemically induced / Q000188:drug therapy*; D004285:Dogs; D005260:Female; D007037:Hypothyroidism / Q000139:chemically induced / Q000662:veterinary*; D008297:Male; D011711:Pyoderma / Q000188:drug therapy / Q000662:veterinary*; D011877:Radionuclide Imaging; D013207:Staphylococcal Skin Infections / Q000188:drug therapy / Q000662:veterinary; D013961:Thyroid Gland / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000503:physiopathology; D013972:Thyrotropin; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000009:adverse effects* / Q000627:therapeutic use
D014284:Triiodothyronine; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D013972:Thyrotropin; D013974:Thyroxine