Use of vanilloids in urologic disorders

Area of Science:

• Urology
• Pharmacology
• Neuroscience

Background:

• The bladder contains vanilloid targets, specifically VR1 vanilloid receptors on c-fibers, which mediate bladder sensation and pain.
• Capsaicin and resiniferatoxin (RTX) are vanilloid receptor agonists that initially excite then desensitize these c-fibers.

Purpose of the Study:

• To examine the literature on vanilloid receptor agonists for treating neurogenic bladder (NGB), overactive bladder (OAB), and interstitial cystitis/painful bladder syndrome (IC/PBS).

Main Methods:

• A literature review was conducted using PubMed with keywords including "capsaicin," "resiniferatoxin (RTX)," "neurogenic bladder," "overactive bladder (OAB)," and "interstitial cystitis/painful bladder syndrome (IC/PBS)."
• Articles focusing on randomized trials comparing intravesical vanilloid administration to placebo, published in English, were reviewed.

Main Results:

• Capsaicin and RTX show acceptable treatment results for neurogenic bladder, but larger studies are needed for confirmation.
• Efficacy for overactive bladder is demonstrated in some studies, but risks associated with catheterization may outweigh benefits, precluding routine recommendation.
• Vanilloid receptor agonists lack strong evidence for efficacy or tolerability in interstitial cystitis/painful bladder syndrome, necessitating larger studies.

Conclusions:

• Vanilloid receptor agonists offer potential for neurogenic bladder treatment, pending further research.
• Current evidence does not support routine use of vanilloids for overactive bladder or interstitial cystitis due to risk-benefit profiles and insufficient data.
• Further understanding of vanilloid mechanisms may elucidate the pathophysiology of these urological disorders.