Current evidence also suggests the efficacy of  dimethyl sulfoxide and amitryptyline therapy .
Hydroxyzine , intravesical bacille Calmette-Guérin  , and  resiniferatoxin therapy  failed to demonstrate efficacy , but evidence was inconclusive owing to method ological limitations .
Pentosan polysulfate may be modestly beneficial for symptoms of PBS/IC .
There is insufficient evidence for other pharmacologic treatments .
BACKGROUND More than 180 different types of therapy have been used in the treatment and management of  painful bladder syndrome/interstitial cystitis ( PBS/IC ) , yet evidence from clinical trials remains inconclusive .
This study aim ed to evaluate the efficacy of pharmacologic approaches to PBS/IC , to quantify the effect size from r and omized controlled trials , and to begin to inform a clinical consensus of treatment efficacy for PBS/IC .
A pilot clinical trial of oral pentosan polysulfate and oral hydroxyzine in patients with interstitial cystitis.
PURPOSE This pilot study was design ed to evaluate the feasibility of a multicenter , r and omized , clinical trial in interstitial cystitis ( IC ) . Secondary objectives were to evaluate the safety and efficacy of oral pentosan polysulfate sodium ( PPS ) , hydroxyzine , and the combination to consider their use in a larger r and omized clinical trial . MATERIAL S AND METHODS A 2 x 2 factorial study design was used to evaluate PPS and hydroxyzine .  Participants met the National Institutes of Health-National Institute for Diabetes and Digestive and Kidney Diseases criteria for IC and reported at least moderate pain and frequency for a minimum of 6 months before study entry . The primary end point was a patient reported global response assessment . Secondary end points included vali date d symptom indexes and patient reports of pain , urgency and frequency . The target sample size was 136 participants recruited during 10 months . RESULTS A total of 121 ( 89 % of goal ) participants were r and omized over 18 months and 79 % provided complete followup data . The response rate for hydroxyzine was 31 % for those treated and 20 % for those not treated ( p = 0.26 ) . A nonsignificant trend was seen in the PPS treatment groups ( 34 % ) as compared to no PPS ( 18 % , p = 0.064 ) . There were no treatment differences for any of the secondary end points . Adverse events were mostly minor and similar to those in previous reports . CONCLUSIONS The low global response rates for PPS and hydroxyzine suggest that neither provided benefit for the majority of patients with IC . This trial demonstrated the feasibility of conducting a multicenter r and omized clinical trial in IC using uniform procedures and outcomes . However , slow recruitment underscored the difficulties of evaluating commonly available IC drugs
Current evidence also suggests the efficacy of  dimethyl sulfoxide and amitryptyline therapy .
Hydroxyzine , intravesical bacille Calmette-Guérin  , and  resiniferatoxin therapy  failed to demonstrate efficacy , but evidence was inconclusive owing to method ological limitations .
Pentosan polysulfate may be modestly beneficial for symptoms of PBS/IC .
There is insufficient evidence for other pharmacologic treatments .
BACKGROUND More than 180 different types of therapy have been used in the treatment and management of  painful bladder syndrome/interstitial cystitis ( PBS/IC ) , yet evidence from clinical trials remains inconclusive .
This study aim ed to evaluate the efficacy of pharmacologic approaches to PBS/IC , to quantify the effect size from r and omized controlled trials , and to begin to inform a clinical consensus of treatment efficacy for PBS/IC .