Kim et al. 2003; USA
PEDro = 9
RCT
N=36

Population: 22 males, 14 females, neurologically impaired patients (20 SCI, 7 multiple sclerosis, 9 other) with urodynamically verified detrusor hyperreflexia
Treatment: Randomized double-blind, placebo-controlled trial. Intravesical instillation of Resiniferatoxin (RTX) 0.005, 0.025, 0.05, 0.10, 0.2, 0.5, or 1.0 microM of RTX (n = 4 each group) or placebo (n=8).
Outcome Measures: incontinence episodes, bladder capacity

1. No statistical significance due to small sample sizes.
2. Intravesical RTX administration was well-tolerated. This patient group was refractory to all previous oral pharmacologic therapy, yet some patients responded with improvement in bladder capacity and continence function shortly after RTX administration.
3. In some cases, mean cystometric capacity increased up to 500% over baseline.
4. Incontinence episodes decreased by over 50% for the 2 highest doses.
5. No data available on long term effect of RXT on AD.

Giannantoni et al. 2002; Italy
PEDro = 6
RCT
N=23

Population: Refractory detrusor hyperreflexia
Treatment: Randomized two treatments
a) single dose of 2 mM. capsaicin in 30 ml ethanol plus 70 ml 0.9% sodium chloride  OR
b) 100 mM. resiniferatoxin in 100 ml 0.9% sodium chloride
Outcome Measures: Urodynamics, frequency of daily catheterizations, incontinence episodes and side effects

1. Capsaicin group showed no significant urodynamic or clinical improvements at 30 and 60 days.
2. Resiniferatoxin group demonstrated significant urodynamic improvement at 30 (p<0.05) and 60 days (p<0.001).
3. Most patients receiving capsaicin, but none receiving resiniferatoxin developed AD, limb spasms, suprapubic discomfort and hematuria.

Igawa et al. 2003; Japan
Downs & Black = 13
Pre-post
N=7

Population: 5 subjects with cervical injuries and 2 subjects with thoracic injuries.
Treatment: bladder instillation with capsaicin solution under general anesthesia.
Outcome Measures: blood pressure, heart rate, serum catecholamines, blood ethanol concentration

1. Capsaicin attenuated elevated BP secondary to bladder distention (empty or full) (p<0.01) post-treatment.
2. In all individuals, episodes of AD become negligible and well tolerated > 3 months.