Cisplatin Toxicity in Cats

Cisplatin (cis‐diamminedichloroplatinum; Platinol, Bristol, Syracuse, NY) was administered to 11 cats, divided into three groups of experimental and clinical patients. In group 1, cisplatin was administered at a dose of 60 mg/m2 to four cats. In an attempt to avoid renal toxicity, saline diuresis was induced by administering 0.9% saline solution intravenously at a rate of 20 ml/kg/hr for 4 hours before and 2 hours after cisplatin administration. All four cats became dyspneic and died 48–96 hours after cisplatin administration. Postmortem findings included severe hydrothorax, pulmonary edema, and mediastinal edema. In group 2, four experimental cats entered a trial comparing the effects of saline diuresis and cisplatin (60 mg/m2) with the effects of saline diuresis and placebo (0.9% saline solution). The cats in the saline control group remained completely normal, while the cats that received cisplatin developed clinical signs and gross postmortem pulmonary changes identical to those in the first group of cats. Histopathologic examination showed that the alveolar septa were thickened and congested, and contained macrophages, occasional neutrophils, thrombi, and small foci of necrosis and fibrin. Microangiopathic changes were seen in the alveolar capillaries. In the third group, three additional cats were treated with a lower dose of cisplatin. Two cats that received 40 mg/m2 of cisplatin developed pulmonary changes similar to, but less severe than, those seen in the cats that received the higher dose of cisplatin. One cat treated with 20 mg/m2 of cisplatin showed no pulmonary changes ante mortem or post mortem. This series of 11 clinical and experimental cases identifies an apparent species‐specific, dose‐related, primary pulmonary toxicity of cisplatin in cats.