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Efficacy and Safety of Gabapentin in Treating Overactive Bladder (OAB)

This study has been completed.
St. Luke's Medical Center, Philippines
Information provided by (Responsible Party):
Michael E. Chua, St. Luke's Medical Center, Philippines Identifier:
First received: December 4, 2011
Last updated: December 29, 2016
Last verified: December 2016
Overactive bladder (OAB) syndrome as defined by International Continence Society is a pathological condition characterized by irritative symptoms: urinary urgency, with or without incontinence, urinary frequency and nocturia. The syndrome often seriously compromises the quality of life of the patients. The etiology of the OAB is considered multifactorial. Neural plasticity of bladder afferent pathways is one of the proposed mechanisms of OAB. The detrusor muscle itself has for many years been the target for drug treatment such as antimuscarinics. However, depression of detrusor contractility, may results in a reduced ability to empty the bladder and lead to some sympathetic adverse effects, which limits the treatment of OAB. Currently the focus of OAB treatment has changed to other bladder structures/mechanisms, such as afferent nerves and urothelial signaling as targets for intervention. C-fiber bladder afferents nerves may be critical for symptom generation in pathologic states such as OAB because these fibers demonstrate remarkable plasticity. Up-regulation of bladder C-fiber afferent nerve function may also play a role in urge incontinence, overactive bladder (OAB) and sensory urgency. The mechanism of Gabapentin's action for neuropathic pain has not been fully elucidated but is appears to have inhibitory activity on afferent C-fibers nerve activity; moreover, several studies had established the safety of Gabapentin in its treatment of different conditions. Due to the proposed mechanism, the investigators suggest that Gabapentin may be a new alternative for treating OAB.

Condition Intervention Phase
Urinary Urgency
Urinary Frequency
Detrusor Uninhibited Activity
Quality of Life
Drug: Gabapentin
Drug: Solifenacin Succinate
Drug: Placebo drugs
Phase 2
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Efficacy and Safety of Gabapentin in Treating Overactive Bladder

Resource links provided by NLM:

Further study details as provided by St. Luke's Medical Center, Philippines:

Primary Outcome Measures:
  • improvement of symptom domain means decreased frequency to less than 8 micturitions per 24 hours, no urgency noted per 24 hrs and less that 3 wakening at bedtime for micturation. [ Time Frame: 12 weeks ]
    Mean number of Micturations per 24 hrs, Mean number of urgency episodes pe 24 hrs, mean urgency incontinence episodes per 24hrs and mean nocturia episodes per 24hrs

Secondary Outcome Measures:
  • Improvement of bladder function domain means increased bladder capacity (MVV) [ Time Frame: 12 weeks ]
  • Improvement in quality of life domain means increased overall quality of life as perceived and result in OAB-q [ Time Frame: 12 weeks ]

Enrollment: 94
Study Start Date: October 2010
Study Completion Date: January 2015
Primary Completion Date: October 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Gabapentin
Two to three months of behavioral therapy prior to start of Gabapentin 100mg/capsule, initially 1 capsule once a day for 1 week then titrate dosage according to symptoms until maximum dose of 1500mg/day Placebo tablet of Solifenacin Succinate will titrate dose same as Solifenacin arm according to symptoms of patient
Drug: Gabapentin
100mg/capsule initially one capsule once a day then titrate according to the symptoms of the patient upto maximum dose of 1500mg/day
Active Comparator: Solifenacin Succinate
Two to three months of behavioral therapy prior to Solifenacin Succinate 5mg/tablet initially 1 tablet once a day then titrate dosage according to symptoms upto maximum dose of 10mg/day Placebo form of Gabapentin will titrate dosage same as Gabapentin group according to symptoms of patient
Drug: Solifenacin Succinate
5mg/tablet initially 1 tablet once a day then titrate up to maximum dose of 10mg/tab
Placebo Comparator: Placebo
Two to three months of behavioral therapy prior to Placebo form of Gabapentin and Solifenacin and titrate accordingly same as the treatment arms
Drug: Placebo drugs
will titrate medications similar to the active drug group


Ages Eligible for Study:   18 Years to 75 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Ambulatory and able to use the toilet without difficulty
  • History of OAB symptoms for ≥ 3 months
  • An average of ≥ 8 micturitions per 24 hours and ≥ 1 urgency episode (with or without incontinence) per 24 hours as documented in a 3-day micturition diary
  • Subjects are bothered by symptoms as reflected by OAB-questionnaire

Exclusion Criteria:

  • Patient has stress or mixed incontinence
  • Patient has Benign Prostatic Hyperplasia with severe lower urinary tract symptoms based on IPSS score
  • Patient has uncontrolled Diabetes Mellitus Type II Patient has Diabetes Insipidus, UTI
  • Patient has history of interstitial cystitis, painful bladder syndrome, or chronic pelvic pain
  • Patient has a history of stroke, seizures, or major neurological disorders
  • Patient has a history of fecal incontinence and or continual urine leakage
  • Patient has had surgery to correct stress urinary incontinence or pelvic organ prolapse within 6 months of study start
  • Patient received bladder training of electrostimulation within 2 weeks of study start
  • Patient requires a catheter
  • Patient is taking medications that cannot be stopped for the duration of the trial including certain anticholinergics or smooth muscle relaxants
  • Patient began taking tricyclic antidepressants, serotonin/norepinephrine reuptake inhibitors, calcium channel blockers, ephedrine/pseudoephedrine, or diuretic therapy less than 8 weeks before study start
  • Patient has been on hormone replacement therapy for less than 12 weeks at study start
  • Patient must take medication for arrhythmia, contraindicated for Solifenacin or Gabapentin
  • Patient has multiple and/or severe allergies to foods and drugs
  • Patient regularly uses any illegal drugs
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Please refer to this study by its identifier: NCT01486706

Comprehensive Pelvic Floor Center- St. Luke's Medical Center
Quezon City, National Capital Region, Philippines, 1102
Sponsors and Collaborators
Michael E. Chua
St. Luke's Medical Center, Philippines
Study Director: Marcelino L Morales JR, MD Institute of Urology, St. Luke's Medical Center, Philippines
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Michael E. Chua, Medical Doctor, St. Luke's Medical Center, Philippines Identifier: NCT01486706     History of Changes
Other Study ID Numbers: SLMC10-010
Study First Received: December 4, 2011
Last Updated: December 29, 2016

Keywords provided by St. Luke's Medical Center, Philippines:
Overactive Bladder
Quality of Life

Additional relevant MeSH terms:
Urinary Bladder, Overactive
Urinary Bladder Diseases
Urologic Diseases
Lower Urinary Tract Symptoms
Urological Manifestations
Signs and Symptoms
Solifenacin Succinate
gamma-Aminobutyric Acid
Muscarinic Antagonists
Cholinergic Antagonists
Cholinergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Urological Agents
Sensory System Agents
Peripheral Nervous System Agents
Antiparkinson Agents
Anti-Dyskinesia Agents
Calcium Channel Blockers
Membrane Transport Modulators
Anti-Anxiety Agents
Tranquilizing Agents
Central Nervous System Depressants
Psychotropic Drugs
Excitatory Amino Acid Antagonists processed this record on April 28, 2017