Effect of intravesical formalin on the urothelium.

In an experimental study, the urinary bladder of the rabbit was subjected to 10% formaldehyde instillation for periods ranging from 15 to 90 min. Varying degrees of cystitis, ranging from focal superficial to transmural necrotising cystitis, epithelial sloughs and intra-epithelial calcification may be seen. The depth of reaction was related approximately to the duration of exposure. Saline irrigation after instillation, contact time of 10 min and 1% formaldehyde seemed to reduce complications.