Oxybutynin, a prescription antispasmodic medication, is used to treat bladder problems from overactive bladder, spina bifida and other conditions that affect the muscles of the bladder. These conditions cause bladder muscle spasms that lead to symptoms of frequent, urgent or uncontrolled urination (incontinence). Oxybutynin treats these symptoms by relaxing the bladder muscles. This medication is available in several forms: extended release tablet, tablet, syrup, patch and gel. Oxybutynin belongs to a class of medications called anticholinergic drugs.