Aims of Study
Chlorpactin has been used to treat IC, though little is known about its mechanism. We measured CGRP levels in urine, bladder wash, and lavage fluids in IC patients undergoing chlorpactin treatment.

Methods
Eight women ages 34-78 were included in this trial. Following urine collection, hydrodistention of the bladder under 80-100cm H2O pressure was carried out. An aliquot of fluid drained following the hydrodistention was obtained. One L chlorpactin (0.4%) was instilled under 10ml H2O pressure. The bladder was then washed with 50cc sterile saline x2, and both were collected for analysis. CGRP was extracted and measured by RIA.

Results
CGRP in the pre- and post-hydrodistention samples was very low, but was highly elevated after chlorpactin treatment. Even in this small sample, levels of CRGP (pg/ml) increased from pre-hydrodistention to the first chlorpactin wash (p=0.16) and decreased again between the first and second post-chlorpactin was (p=0.21).

Conclusions
Chlorpactin may act by degranulating nociceptive nerve endings in the bladder, which is consistent with the neuro-inflammatory hypothesis for IC.

Direct correspondence to:
Karl J. Kreder, MD University of Iowa Department of Urology 200 Hawkins Dr., 3 RCP Iowa City, IA 52242-1089 USA telephone: 319-356-4525 fax: 319-356-3900 email: karl-kreder@uiowa.edu