(R)-Hydroxytolterodine-d 14 is deuterated labeled Desfesoterodine. Desfesoterodine (PNU-200577) is a potent and selective muscarinic receptor ( mAChR ) antagonist with a K B and a pA 2 of 0.84 nM and 9.14, respectively. Desfesoterodine is a major pharmacologically active metabolite of Tolterodine (PNU-200583) and Fesoterodine. Desfesoterodine improves cerebral infarction induced detrusor overactivity in rats.