NCT00124306

Efficacy of Amitriptyline for Painful Bladder Syndrome (PBS)

A Randomized Multicenter Clinical Trial to Evaluate the Efficacy of Amitriptyline for the Treatment of Painful Bladder Syndrome (PBS) in Newly Diagnosed Patients

• Status: Completed
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 271 (actual)
• Sponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) · NIH
• Sex: All
• Age: 18 Years
• Healthy volunteers: Accepted

Summary

This is a randomized clinical trial study to test the efficacy and safety of amitriptyline in the treatment of patients newly diagnosed with painful bladder syndrome (PBS). PBS is defined by symptoms--frequent urination day and night and increasing pain as the bladder fills--according to the International Continence Society. The syndrome includes interstitial cystitis (IC), which has been estimated to affect as many as 700,000 people, mostly women. Estimates for PBS vary widely, but as many as 10 million people may suffer from this condition. Although amitriptyline is a Food and Drug Administration (FDA)-approved medication used for depression, the way it works makes it useful for treating the pain of fibromyalgia, multiple sclerosis, and other chronic pain syndromes. Prior small studies in interstitial cystitis (IC) suggested the drug may be a wise choice for this syndrome as well, because it blocks nerve signals that trigger pain and may also decrease muscle spasms in the bladder, helping to relieve the symptoms of pain and frequent urination.

Detailed description

The current trial is recruiting newly diagnosed adults who have not yet received treatment. Approximately 270 participants will be randomly assigned to take up to 75 milligrams of amitriptyline or a placebo each day for 14 to 26 weeks. All participants will be given techniques to practice suppressing the urge to urinate for increasingly longer stretches until they can wait 3 or 4 hours before going to the bathroom. Participants will also regulate when and how much they drink and avoid bladder irritants such as alcohol, acidic foods and carbonated or caffeinated drinks. Staff and patients will find out who received the amitriptyline when the study is finished. Medications and tests are free to participants. Ten medical centers in the United States and Canada are recruiting adults newly diagnosed with either painful bladder syndrome (PBS) or interstitial cystitis (IC).The centers make up the Interstitial Cystitis Clinical Research Network, sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) at NIH.

Conditions

• Bladder Diseases
• Interstitial Cystitis

Interventions

Type	Name	Description
DRUG	Amitriptyline	Amitriptyline will be titrated over a 6-week period as tolerated, to a maximum dose of 75mg. During the 6-week titration period, the patient who cannot tolerate a scheduled increased dose may adjust the medication dose for tolerance by tapering down one 25mg tablet.
OTHER	Placebo	Placebo will be dosed exactly as active arm.

Timeline

• Start date: 2005-02-01
• Primary completion: 2008-04-01
• Completion: 2008-12-01
• First posted: 2005-07-27
• Last updated: 2026-01-12
• Results posted: 2025-10-07

Locations

10 sites across 2 countries: United States, Canada

Regulatory

• FDA-regulated drug study