5.2.2. Dimethyl Sulphoxide

Dimethyl sulphoxide (DMSO) intravesical instillation was developed some decades ago by Stewart et al. [19]. Now, DMSO is an FDA-approved second-line therapy for IC/BPS [20]. DMSO, an organic solvent, can desquamate urothelium, disrupt mucosa, and interfere with cellular phospholipid membranes. In addition, DMSO luminal effluent leads to a loss of urothelial layers and mucosal folding; thus, it facilitates membrane penetration to increase urothelium permeability and to cause leakage of cytosolic contents. Besides, DMSO was found to inhibit the stretch-activated adenosine triphosphate release from urothelial cells and relax the detrusor muscle in rabbits [21].

Petrou et al. conducted a phase 1/2 study in treating refractory idiopathic detrusor overactivity in women by using 300 U of onaBoNTA plus 50% DMSO solution for instillation [22]. The results demonstrated that patients who underwent this treatment had improved incontinence events, decreased Indevus Urgency Severity Scale scores, and improved quality of life as recorded by questionnaires (i.e., 6-item Urogenital Distress Inventory, bothersome score, and Incontinence Impact Questionnaire short-form) at the endpoint of the 3-month observation.
