Efficacy of Amitriptyline for Painful Bladder Syndrome (PBS) (IC01)

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

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.

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.

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.

Inclusion Criteria: Participant must report bladder pain/discomfort score of 3 or greater on a 0-10 Likert scale over the previous 4 weeks. Participant must report a symptom score of abnormal urinary frequency of 3 or greater on a 0-10 Likert scale over the previous 4 weeks. Symptoms of abnormal urinary frequency and bladder pain/discomfort must have been present for at least six weeks prior to screening visit. Exclusion Criteria: Known allergy or intolerance to amitriptyline or any of its components. Currently receives treatment with amitriptyline or other tricyclic antidepressant, selective serotonin reuptake inhibitor (SSRI) or serotonin and norepinephrine reuptake inhibitor (SNRI), or monoamine oxidase (MAO) inhibitor antidepressants. Previous treatment with amitriptyline or other tricyclics, hydroxyzine or other antihistamines for bladder symptoms; pentosanpolysulfate; DMSO or any other intravesical therapy, biofeedback or pelvic floor physical therapy for PBS symptoms

Imamura M, Scott NW, Wallace SA, Ogah JA, Ford AA, Dubos YA, Brazzelli M. Interventions for treating people with symptoms of bladder pain syndrome: a network meta-analysis. Cochrane Database Syst Rev. 2020 Jul 30;7(7):CD013325. doi: 10.1002/14651858.CD013325.pub2.

Foster HE Jr, Hanno PM, Nickel JC, Payne CK, Mayer RD, Burks DA, Yang CC, Chai TC, Kreder KJ, Peters KM, Lukacz ES, FitzGerald MP, Cen L, Landis JR, Propert KJ, Yang W, Kusek JW, Nyberg LM; Interstitial Cystitis Collaborative Research Network. Effect of amitriptyline on symptoms in treatment naive patients with interstitial cystitis/painful bladder syndrome. J Urol. 2010 May;183(5):1853-8. doi: 10.1016/j.juro.2009.12.106. Epub 2010 Mar 29.