Col Amit Agrawal
Army Hospital (Research & Referral)
Delhi Cantt, New Delhi
Recently, Botulinum Toxin (BTX-A) has been added to the urologist’s armamentarium as an alternative management option in patients with IC/BPS not responding to the conventional treatment. BTX-A is a neurotoxin and its action in patients with IC/BPS is mediated by its effects on the peripheral sensory nerves, central nervous system as well as by a direct action on the bladder (figure 1).
BTX-A has been traditionally given as suburothelial injections (100-200 units) over 20-30 sites in the body of the bladder, however, intra-trigonal injections have also been tried. Repeated injections (6 monthly intervals; at least 4 times) are usually required and were found to be more effective in providing a sustained pain relief. Also, the trigonal injections were equally efficacious in both Hunner lesion and non-Hunner lesion type of IC/BPS,(1) while injections into the body of bladder were less effective in the Hunner lesion type of IC/BPS.(2)
Figure 1: Mechanism of action of BTX-A in patients with IC/BPS
As far as the efficacy is concerned, BTX-A injections result in reduced frequency, urgency, and urge incontinent episodes as well as a reduction in pain in patients with IC/BPS. A recent systematic review found that BTX-A reduced the mean daytime frequency by 2.9 times, the nocturia by a mean 0.6 episodes per night and the capacity was increased by 78ml.(3) BTX-A also improves the pain as evidenced by a 50% reduction in the need of oral pain medications and the VAS decreases from 10 to 5 after treatment. An improvement of 71% and 69% was reported in The Interstitial Cystitis Symptom Index and Interstitial Cystitis Problem Index mean scores, respectively and the majority of the studies reported a high initial efficacy rate, ranging from 74% to 86% at three months. However, in absence of placebo-controlled trials, the true effectiveness of the therapy is difficult to determine.
A recent RCT explored the possibility of intravesical instillation of BTX-A in a liposome encapsulated form, instead of the usual suburothelial inj, but could not find therapeutic superiority as compared with a placebo.(4)
One of the major disadvantages of BTX-A is the need for a repeat dose/alternate therapy, as the effect lasts only for a few months, with a study reporting a low efficacy rate at three months (20%) and return to baseline symptoms in all the patients at one year of follow-up.
Thus to conclude, in the absence of placebo-controlled studies, the true effect of BTX-A is difficult to determine. However, overall, the literature suggests that a subset of patients experience a relief in the symptom for several months, with a return to baseline symptom levels over time.
Key points
BTX-A: IC/BPS |
Can be tried in IC/BPS not responding to conventional Rx |
BTX-A: 100-200U, sub-urothelial, 20-30 sites |
Improves LUTS & pain scores |
Benefit weans over time |
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