Toxicities and salvage therapy following overdose of vinblastine in a cat.

A cat receiving chemotherapy for lymphoma was administered a four times overdose of vinblastine in error. Severe, acute life-threatening toxicities occurred. The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) was suspected based on electrolyte disturbances. A favourable outcome was achieved with aggressive supportive care. Personnel involved in administering chemotherapy to small animal patients must check that the patient is receiving the correct drug, at the appropriate dose, prior to every treatment.