ABSTRACT
Botulinum toxin (BTX), first isolated by van Ermengem in 1895, is the most potent biological agent known to man.1 BTX’s mechanism of action has been traditionally described as inhibiting acetylcholine release at the presynaptic cholinergic junction. However, in later sections we will present evidence that BTX could inhibit other transmitter systems and cellular processes also thought to play an important role in the development of bladder overactivity. Clinically, the urologic community’s initial experience with botulinum toxin A (BTX-A) was to treat bladder overactivity resulting from neurologic insult (i.e. spinal cord injury, etc.). Over the past few years, however, use of BTX-A has been expanded to treat patients with non-neurogenic overactive bladder (OAB). The rapid expansion in the use of BTX to treat OAB is due, in large part, to the inadequacy of current standard pharmacologic treatment (i.e. antimuscarinic agents) as well as to the demonstration of BTX’s efficacy, durability, and tolerability in early clinical series. However, at the time of this writing, use of BTX in the bladder is Food and Drug Administration (FDA) off-label, and caution should be exercised until randomized clinical trials are completed. The purpose of this chapter is to review the mechanisms underlying the effects of botulinum toxin treatment and to summarize the current off-label usage of this agent to treat OAB, including clinical results, injection techniques, and adverse events.
