Effects of oral administration of furosemide and torsemide in healthy dogs.
OBJECTIVE
To investigate the diuretic effects, tolerability, and adverse effects of furosemide and torsemide after short- and long-term administration in healthy dogs.


METHODS
8 mixed-breed dogs.


METHODS
In a crossover study, furosemide (2 mg/kg), torsemide (0.2 mg/kg), or placebo (bifidobacterium [1 mg/kg]) was administered orally to each dog every 12 hours for 14 days. Blood and urine samples were collected before the study (baseline data) and at intervals on the 1st (short-term administration) and 14th day (long-term administration) of treatment for assessment of urine volume and specific gravity and selected clinicopathologic variables including BUN, creatinine, and aldosterone concentrations, and creatinine clearance.


RESULTS
Compared with the baseline value, short-term administration of furosemide or torsemide immediately increased urine volume significantly; after long-term administration of either drug, urine specific gravity decreased significantly. Compared with the effect of placebo, the 24-hour urine volume was significantly increased after short-term administra-tion of furosemide or torsemide. In addition, it was significantly increased after long-term administration of torsemide, compared with that of short-term administration. Long-term administration of furosemide or torsemide increased the BUN and plasma creatinine con-centrations, compared with the baseline value. Compared with the baseline value, plasma aldosterone concentration was significantly increased after long-term administration of either drug and was significantly higher after torsemide treatment than after furosemide treatment.


CONCLUSIONS
In dogs, diuretic resistance developed after 14 days of furosemide, but not torsemide, administration; however, both loop diuretics were associated with increased BUN and plasma creatinine concentrations, compared with values before treatment.
Hori
Yasutomo
Y
Department of Small Animal Internal Medicine, School of Veterinary Medicine, Kitasato University, 23-35-1 Higashi, Towada, Aomori 034-8628, Japan.
Takusagawa
Fumihiko
F
Ikadai
Hiromi
H
Uechi
Masami
M
Hoshi
Fumio
F
Higuchi
Sei-ichi
S
D000284:Administration, Oral; D000818:Animals; D001798:Blood Proteins / Q000187:drug effects / Q000378:metabolism; D001806:Blood Urea Nitrogen; D001835:Body Weight; D003404:Creatinine / Q000097:blood; D004232:Diuretics / Q000008:administration & dosage / Q000494:pharmacology*; D004285:Dogs / Q000502:physiology*; D005260:Female; D005665:Furosemide / Q000008:administration & dosage / Q000494:pharmacology*; D006400:Hematocrit; D008297:Male; D010919:Placebos; D013449:Sulfonamides / Q000008:administration & dosage / Q000494:pharmacology*; D000077786:Torsemide; D014556:Urine / Q000502:physiology
D001798:Blood Proteins; D004232:Diuretics; D010919:Placebos; D013449:Sulfonamides; D005665:Furosemide; D003404:Creatinine; D000077786:Torsemide