Acute pancreatitis in two dogs given azathioprine and prednisone

Acute pancreatitis was diagnosed in 2 dogs given azathioprine and prednisone. Prednisone and azathioprine had been given as immunosuppressive therapy for pemphigus foliaceus in dog 1 and for polymyositis in dog 2. Azathioprine was discontinued in both dogs. In dog 1, prednisone was reinstituted on day 6 of hospitalization. Prednisone was continued throughout the period of hospitalization in dog 2. Both dogs recovered without complication. Glucocorticoid therapy has been associated with the development of pancreatitis. In human beings, a common side effect of azathioprine is the development of drug-induced pancreatitis. Definitive identification of azathioprine as the cause of pancreatitis in these dogs was not possible; the owners refused to permit retreatment with the drug. Therefore, the synergistic action between these 2 drugs could not be ruled out as the cause of pancreatitis.