Hemodynamic effects of methylprednisolone acetate administration in cats.
OBJECTIVE
To investigate the mechanisms by which corticosteroid administration may predispose cats to congestive heart failure (CHF).


METHODS
12 cats receiving methylprednisolone acetate (MPA) for the treatment of dermatologic disorders.


METHODS
The study was conducted as a repeated-measures design. Various baseline variables were measured, after which MPA (5 mg/kg, IM) was administered. The same variables were then measured at 3 to 6 days and at 16 to 24 days after MPA administration. Evaluations included physical examination, systolic blood pressure measurement, hematologic analysis, serum biochemical analysis, thoracic radiography, echocardiography, and total body water and plasma volume determination.


RESULTS
MPA resulted in a substantial increase in serum glucose concentration at 3 to 6 days after administration. Concurrently, RBC count, Hct, and hemoglobin concentration as well as serum concentrations of the major extracellular electrolytes, sodium and chloride, decreased. Plasma volume increased by 13.4% (> 40% in 3 cats), whereas total body water and body weight slightly decreased. All variables returned to baseline by 16 to 24 days after MPA administration.


CONCLUSIONS
These data suggest that MPA administration in cats causes plasma volume expansion as a result of an intra to extracellular fluid shift secondary to glucocorticoid-mediated extracellular hyperglycemia. This mechanism is analogous to the plasma volume expansion that accompanies uncontrolled diabetes mellitus in humans. Any cardiovascular disorders that impair the normal compensatory mechanisms for increased plasma volume may predispose cats to CHF following MPA administration.
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, 1365 Gortner Ave, Saint Paul, MN 55108, USA.
Trasida
T
Ployngam
Anthony H
AH
Tobias
Stephanie A
SA
Smith
Sheila M F
SM
Torres
Sheri J
SJ
Ross
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D002371:Cat Diseases / Q000188:drug therapy*; D002415:Cats; D002712:Chlorides / Q000097:blood; D003971:Diastole / Q000187:drug effects; D004906:Erythrocyte Count; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology*; D008775:Methylprednisolone / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000077555:Methylprednisolone Acetate; D012871:Skin Diseases / Q000188:drug therapy / Q000662:veterinary*; D012964:Sodium / Q000097:blood; D013599:Systole / Q000187:drug effects
D000893:Anti-Inflammatory Agents; D002712:Chlorides; D000077555:Methylprednisolone Acetate; D012964:Sodium; D008775:Methylprednisolone