Painful sexual relations occurs in over 75% of IC patients. Researchers instilled a solution in the bladders of 21 sexually active IC patients, three times per week for three weeks. The solution contained lidocaine (a localized painkiller), heparin (to coat a hypothetically leaky bladder lining), and bicarbonate (basically baking soda– as a buffer). Before the instillations began, the researchers evaluated the vaginal tenderness of each patient and then divided the patients into two groups: those with pain only at the vaginal wall closest to the bladder, and those with pain elsewhere in the vagina as well.
Twelve of the patients (57%) reported no dyspareunia at all after the series of instillations. Of those who no longer had dyspareunia, 10 (83%) were women who, on the initial examination, only had tenderness of the vaginal wall closest to the bladder. Two of those no longer having dyspareunia had, on initial exam, vaginal tenderness at other sites. Those patients who initially had tenderness only on the vaginal wall closest the bladder also had superior improvement in their urgency, frequency and pain, as compared to patients with initial tenderness throughout the vagina. The authors suggest that larger controlled trials are needed to confirm the findings of this small-scale study.