Efficacy of Gralise® for Chronic Pelvic Pain

Inclusion Criteria: * 18 years of age and older * English speaking * able to give consent * willing to use electronic diary during entire length of the study * has 'chronic' pelvic pain * Meets one of the following diagnostic criteria for one of the following: Irritable Bowel Syndrome (IBS) Ulcerative Colitis (UC), Interstitial Cystitis (IC), and Prostatitis Exclusion Criteria: * allergic to gabapentin or inactive ingredients * taking gabapentinoids (i.e. gabapentin or pre-gabalin) * with severe or unmanaged psychiatric disturbance (at PI discretion) * with severe ongoing or unaddressed medical conditions (esp. Renal or Hepatic disease, uncontrolled hypertension), rheumatologic disease, narrow angle glaucoma, hyponatremia, clotting disorders, uncontrolled seizure disorder or urinary retention. * who plan to change their therapeutic regimen during the course of the trial (e.g. start physical therapy, massage, medications, injections, etc.) * with acute pain Female subjects: * pregnant or plan to become pregnant * gave birth within the last 6 months * breastfeeding * episodic visceral pain (e.g. endometriosis)