Hydrodistention Hydrodistention is an outpatient procedure done under general anesthesia that fills your bladder with water until it stretches. It is done using a long thin camera called a cystoscopy. It is often done in conjunction with other procedures. At the time of the hydrodistention a medication, dimethyl sulfoxide, may be placed in the bladder. This medication helps reduce inflammation, relax the bladder, relieve pain, and increase bladder storage by helping break down scar tissue. If bladder ulceration is seen the ulcers can be cauterized or have steroid injected in them giving symptomatic relief for up to a year.