Botox has been available for more than 20 years. During that time it has become a household word, associated with cosmetic injections to smooth facial wrinkles. Now the FDA has approved it for treating overactive bladder. A Botox injection into bladder muscle increases capacity and reduces urinary incontinence. Repeat injections may be needed, but should not be done more frequently than every 12 weeks. Side effects from the Botox injection include incomplete bladder emptying, painful urination and urinary tract infections. Overactive bladder is frequently treated with medications that also have side effects such as constipation, confusion, dry mouth and dry eyes. Botox injections are intended for people who cannot tolerate these drugs.