Intravesical instillation of dilute formalin for treatment of cyclophosphamide-induced hemorrhagic cystitis in two dogs.

Sterile hemorrhagic cystitis induced by cyclophosphamide therapy was diagnosed in 2 dogs. Clinical signs included pollakiuria, hematuria, and stranguria. The signs were progressive and referable to long-term oral cyclophosphamide administration. Dilute (1%) formalin was used to treat the hemorrhagic cystitis. Clinical control of hemorrhage was achieved in both cases, and hemorrhage did not recur.