Intravesical Therapy

Success of intravesical administration of anticholinergics for overactive bladder and detrusor hyperreflexia has been documented in many studies.15 However, secondary to the cumbersome nature of administration and the relatively short duration of action requiring repeated catheterization, intravesical anticholinergic drug therapy is not widely accepted.

Intravesical administration of local anesthetics such as lidocaine has been shown to be effective for suppressing overactive bladder, but secondary to its short-term effectiveness, the use of intravesical lidocaine is limited to its diagnostic use for differentiating detrusor hyperactivity caused by lesions of the spinal cord versus lesions of the brain.

Intravesical peppers or vanilloids such as capsaicin and resiniferatoxin (RTX) activate nociceptor sensory nerve fibers known as vanilloid receptor subtype 1. These receptors function as transducers of painful thermal stimuli, and are located predominantly on C fiber bladder afferent nerves. Activation of these receptors initially excites these nerves, but ultimately results in desensitization. C fiber hyperactivity has been identified in patients with idio-pathic detrusor hyperactivity,multiple sclerosis, and spinal cord injuries.15

Intravesical capsaicin and RTX are still considered experimental, but in a recent meta-analysis of published studies, the beneficial clinical effects of increased bladder capacity on cystometrics and mean symptomatic improvement were noted in approximately 72%, and may last up to 1 year.15 The side effects are acute burning and pain, as initial instillation causes stimulation of the unmyelinated C fibers. Resiniferatoxin is markedly more potent than capsaicin as a vanilloid receptor agonist, but causes significantly less local pain and inflammatory neurotrans-mitter release.

Botulinum toxin (Botox) inhibits acetylcholine release at the presynaptic membrane, thereby decreasing muscle contractility and causing muscle atrophy at the site of injection. This action is temporary because the nerves regenerate in 3 to 6 months. Traditionally, botulinum toxin has been used to treat detrusor-sphincter dyssynergia because the toxin produces a chemical denervation at the neuromuscular junction of the external sphincter. Schurch et al.16 demonstrated increases in mean maximum bladder capacity of 296 to 480 mL (P < .016) and a decrease in mean maximum detrusor voiding pressure of 65 to 35 cm H2O (P < .016) measured 6 weeks after injection in spinal cord-injured patients with detrusor hyperreflexia who received intravesical injection at up to 30 sites.

In our experience, patients respond well to Botox injections, but symptoms are likely to recur within 6 months. Limited clinical data are available on Botox for OAB, and it is not FDA approved for this indication.

5 Common Skin Problems Answered

5 Common Skin Problems Answered

Our skin may just feel like a mere shield that protects us from the world outside. But, the fact is, its more than just the mask that keeps your insides in. It is a very unique and remarkable complex organ that reflects our general health.

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