January 15, 2017 Liza Colimon, MD Bladder instillations are used to place numbing medications into the bladder for temporary pain relief due to interstitial cystitis. This procedure may also be performed to test for bladder mucosal sensitivity. First the urethra is cleaned with betadine soap. A small catheter is placed in the bladder. Through this catheter a mixture of anesthetic medications is placed. The entire procedure is done in the office setting.