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Pilot Study of Cyclobenzaprine for Treatment of Sleep Disturbance in Aromatase Inhibitor-treated Breast Cancer Patients

This study has been terminated.
(Accrual terminated early because of poor accrual)
Damon Runyon Cancer Research Foundation
Information provided by (Responsible Party):
Lynn Henry, University of Michigan Cancer Center Identifier:
First received: August 8, 2013
Last updated: March 21, 2016
Last verified: March 2016
Many women with breast cancer who are treated with aromatase inhibitor medications develop difficulty sleeping and fatigue during treatment. Some examples of aromatase inhibitor medications include anastrozole (Arimidex), exemestane (Aromasin), and letrozole (Femara). Frequently, sleeping pills do not work very well to improve sleep. Cyclobenzaprine (Flexeril) is a medication that was originally developed to treat muscle spasms. It may also improve sleep in patients with chronic pain disorders, such as fibromyalgia. In this study we are testing to see if cyclobenzaprine at bedtime will help improve sleep in women treated with aromatase inhibitors.

Condition Intervention Phase
Sleep Initiation and Maintenance Disorders
Drug: Cyclobenzaprine
Phase 2

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Supportive Care
Official Title: UMCC 2013.051: Prospective Pilot Study Evaluating the Use of Cyclobenzaprine for Treatment of Sleep Disturbance, Fatigue, and Musculoskeletal Symptoms in Aromatase Inhibitor-treated Breast Cancer Patients

Resource links provided by NLM:

Further study details as provided by University of Michigan Cancer Center:

Primary Outcome Measures:
  • Number of Patients That Experience an Improvement in Sleep Quality as Assessed Using the Pittsburgh Sleep Quality Index (PSQI) With 8 Weeks of Cyclobenzaprine Therapy. [ Time Frame: 8 weeks ]
    Will measure sleep quality using the Pittsburgh Sleep Quality Index at baseline and after 8 weeks of therapy with cyclobenzaprine. A total score is calculated for the Pittsburgh Sleep Quality Index. The total score ranges from 0-21, with higher scores representing worse sleep quality. Any reduction in PSQI total score was considered an improvement.

Secondary Outcome Measures:
  • Change in Fatigue Between Baseline and Week 8 With Cyclobenzaprine Therapy [ Time Frame: baseline and 8 weeks ]
    Will measure fatigue using the PROMIS fatigue questionnaire at baseline and after 8 weeks of therapy with cyclobenzaprine. The PROMIS Fatigue 7a score was calculated according to the information provided on the website. The raw score ranges from 7-35. The raw score is then converted to a T score according to the instruction on the website, with higher scores representing more fatigue. The T score rescales the raw score into a standardized score with a mean of 50 and a standard deviation of 10. The change in fatigue is calculated by subtracting the T score at baseline from the T score at 8 weeks. Positive values represent worsening of fatigue.

  • Change in Average Pain Between Baseline and Week 8 With Cyclobenzaprine Therapy [ Time Frame: baseline and 8 weeks ]
    Will measure average pain using the Brief Pain Inventory at baseline and after 8 weeks of therapy with cyclobenzaprine. On the Brief Pain Inventory, average pain is reported using a 0-10 scale, with higher numbers reflecting more pain. Change is calculated by subtracting pain at baseline is from pain at 8 weeks. A positive value represents an increase in pain.

Other Outcome Measures:
  • Percentage of Subjects Who Continue to Take Aromatase Inhibitor Therapy [ Time Frame: 24 weeks ]
    We will assess the number of patients who continue to take the original aromatase inhibitor medication at the 24 week timepoint, as assessed using patient self-report and medical records

  • Percentage of Patients That Experience Adverse Events [ Time Frame: 24 weeks ]
    Persistence with cyclobenzaprine therapy for 24 weeks will be assessed using a medication diary. Safety will be assessed using CTCAE criteria

Enrollment: 2
Study Start Date: August 2013
Study Completion Date: April 2015
Primary Completion Date: May 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Cyclobenzaprine
Cyclobenzaprine (Flexeril) 5 milligrams orally 2 hours before bed, for a total of 24 weeks.
Drug: Cyclobenzaprine
5 milligrams orally 2 hours before bedtime
Other Name: Flexeril


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Female gender, age ≥ 18, postmenopausal.
  • Histologically proven stage 0-III invasive carcinoma of the breast
  • Initiating or have been receiving a standard dose of aromatase inhibitor therapy (letrozole 2.5mg once daily or exemestane 25mg once daily or anastrozole 1mg once daily) for up to a total of 48 months of AI therapy.
  • Trouble sleeping during the past week. (After signing the informed consent document, subjects must also have a global PSQI score of ≥5)
  • ECOG performance status 0-2 (see Appendix A).

Exclusion Criteria:

  • Known hypersensitivity to cyclobenzaprine or any of the inactive ingredients
  • Diagnosis of sleep apnea that is currently interfering with sleep or requiring CPAP, restless leg syndrome that is currently interfering with sleep or requiring medication, or Epworth sleepiness scale >10.
  • Subjects with a history of hypothyroidism must have been on a stable dose of thyroid replacement medicine for at least 3 months prior to enrollment
  • Treatment with steroids within 1 month
  • Treatment with monoamine oxidase inhibitors (MAO-I) within 14 days of enrollment.
  • Concurrent treatment with bupropion, MAO inhibitors, phenothiazines (including thioridazine), selegiline, tramadol, or medications known to prolong the QT interval (
  • Currently primary psychiatric diagnosis (schizophrenia, psychosis) or suicidal ideation, history of bipolar disorder, or seizure disorder
  • Known moderate or severe hepatic impairment
  • History of congestive heart failure or cardiac arrhythmia (other than atrial fibrillation); myocardial infarction within the past 6 months
  • Uncontrolled narrow-angle glaucoma
  • Pregnant or breast feeding
  • Serious or unstable medical condition that could likely lead to hospitalization during the course of the study or compromise study participation
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Please refer to this study by its identifier: NCT01921296

United States, Michigan
University of Michigan Comprehensive Cancer Center
Ann Arbor, Michigan, United States, 48109-0944
Sponsors and Collaborators
Lynn Henry
Damon Runyon Cancer Research Foundation
Principal Investigator: Norah L Henry, MD, PhD University of Michigan
  More Information

Additional Information:
Responsible Party: Lynn Henry, Assistant Professor of Internal Med, University of Michigan Cancer Center Identifier: NCT01921296     History of Changes
Other Study ID Numbers: UMCC 2013.051
Study First Received: August 8, 2013
Results First Received: November 12, 2014
Last Updated: March 21, 2016

Keywords provided by University of Michigan Cancer Center:
Breast cancer
Aromatase inhibitor

Additional relevant MeSH terms:
Breast Neoplasms
Sleep Initiation and Maintenance Disorders
Sleep Wake Disorders
Neoplasms by Site
Breast Diseases
Skin Diseases
Sleep Disorders, Intrinsic
Nervous System Diseases
Mental Disorders
Neurologic Manifestations
Signs and Symptoms
Aromatase Inhibitors
Steroid Synthesis Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Estrogen Antagonists
Hormone Antagonists
Hormones, Hormone Substitutes, and Hormone Antagonists
Physiological Effects of Drugs
Antidepressive Agents, Tricyclic
Antidepressive Agents
Psychotropic Drugs
Muscle Relaxants, Central
Neuromuscular Agents
Peripheral Nervous System Agents processed this record on May 23, 2017