Can you suggest medicine for overactive bladder? Plz...

Same as urge leakage. Overactive bladder is prelude to urge incontinence. As such your doctor can offer you any number of antimuscarinics such as oxybutynin. However, they're all reasonably effective w/o any particular one being significantly better than another. Check out http://alvinblin.Blogspot.Com/2012/06/whats-best-medicine-to-treat-urinary.Html for recent study looking at this class of medications.