How is botulinum toxin A used in treating urinary incontinence?

• A. Injected into the detrusor muscle to reduce detrusor overactivity and increase bladder capacity.
• B. Orally as daily tablets.
• C. Injected into the urethra.
• D. Applied topically to bladder.

Answer: (A)

Botulinum toxin A treats urinary incontinence by quieting an overactive bladder. It is given as injections directly into the detrusor muscle of the bladder (usually during cystoscopy). By blocking acetylcholine release at the neuromuscular junction in the detrusor, it reduces involuntary contractions, increases bladder capacity, and lowers urgency and leakage. It is not taken by mouth, not injected into the urethra, and not applied to the skin. The effects wear off over several months and may require repeat injections; potential risks include urinary retention and urinary tract infections.