Cyclobenzaprine Extended Release (ER) for Fibromyalgia

October 5, 2021 updated by: Thomas L. Schwartz, M.D., State University of New York - Upstate Medical University

An Eight Week, Double-Blind Efficacy Study of Cyclobenzaprine ER (Amrix TM) Augmentation to Alleviate Fibromyalgia Fatigue and Muscle Pain

Amrix (Cyclobenzaprine hydrochloride Extended release capsules) is approved by the FDA as a muscle relaxant, indicated for the treatment of muscle spasm associated with acute, painful musculoskeletal conditions. Cyclobenzaprine ER (Amrix TM) has a distinct pharmacokinetic profile providing early systemic exposure and consistent plasma concentration over several hours. Overall, a single dose of Amrix 30 mg is similar to that of cyclobenzaprine immediate release 10 mg three times daily. This ER formula should improve compliance, with similar efficacy and possibly less side effects as is often the case with slower release formulations.

There are clinical studies showing that cyclobenzaprine can alleviate pain secondary to Fibromyalgia induced muscle tone. This multi-layered evidence base suggests that cyclobenzaprine may be able to alleviate pain in fibromyalgia. Theoretically in fibromyalgia, pain is interpreted centrally and possibly occurs due to said muscle spasm . Cyclobenzaprine may relieve this pain, thus allowing patients to function better during the day and sleep better at night. Cyclobenzaprine has tricyclic antidepressant structure which may also allow pain signal dampening in the spinal cord as well, similar to amitriptyline which is used off-label for neuropathic pain as well.

Fibromyalgia (FM) is an illness that may involve medical, rheumatologic, autoimmune, sleep, endocrine and psychiatric pathology. It is a syndrome of recurrent pain at trigger points. Greater than 90% of these patients will report fatigue as a key symptom as well. There are several investigation lines into the treatment of FM induced pain. Exercise, behavioral therapy, amitryptiline, duloxetine, tramadol, sodium oxybate, pregabalin all have randomized trials and almost all focus on pain. There are very few studies evaluating cyclobenzaprine and none studying to Cyclobenzaprine ER formulation. None evaluate pain reduction, sleep and fatigue improvement.

Cyclobenzaprine is a drug with minimal adverse effects (dry mouth, dizziness, fatigue, constipation, somnolence, nausea, and dyspepsia). It may have a safer tolerability profile than some of the FM medications noted above. As cyclobenzaprine is often studied and often added as an augmentation agent to patients' regimens who suffer from acute painful musculoskeletal conditions, the authors feel that cyclobenzaprine would also be effective in this population. The authors wish to conduct a study to determine if cyclobenzaprine ER is safe and tolerable in the treatment of FM induced pain, and secondary fatigue and insomnia. This initial study may allow for continued regulatory studies with this product in FM subjects. The authors propose a double-blind placebo controlled study to determine if cyclobenzaprine ER is safe and effective in reversing FM induced pain, and secondary fatigue and insomnia.

Study Overview

Status

Terminated

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

37

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • New York
      • Syracuse, New York, United States, 13210
        • SUNY Upstate Medical University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

If possible, 60 subjects will be included in this study.

  • All males/females of any race are eligible if aged between 18 and 65 and
  • Subjects must speak English and have capacity to receive and utilize informed consent
  • Agree to use barrier method contraception or are infertile x 2 years due to medical condition or surgery
  • Have been formally diagnosed by a Board Certified Rheumatologist using the ACR 1990 research criteria for fibromyalgia
  • Report that pain is a key distressing symptom of their FM
  • Have a score of > 4 on the Visual Analogue Pain Scale (VAPS)

Exclusion Criteria: Subjects cannot

  • Be pregnant or be attempting to conceive at present (urine bHCG must be negative)
  • Have an active substance abuse problem with last use within the past 90 days (outside of nicotine)
  • Use cardiac QTc prolonging medications i.e., tricyclic antidepressants
  • Use p4502D6 major inhibiting medications as cyclobenzaprine levels may increase
  • Have a known medical condition outside of FM that causes pain, i.e., diabetic neuropathy
  • Have a known medical condition or other medication use that relatively contraindicates cyclobenzaprine use (i.e., hypersensitivity concomitant use of monoamine oxidase (MAO) inhibitors, seizures, known cardiac abnormalities, recent MI. hepatitis, stroke, or psychosis
  • Has a prior history of cyclobenzaprine use and failure (failure due to side effects may be allowed at P.I. discretion)
  • Be receiving daytime/nighttime sedating medication with clear chronological impact on fatigue UNLESS fatigue predates sedating medication or said medication has been steadily dosed > 4 weeks
  • Other medications known to alleviate pain (i.e., Gabapentin, Pregabalin, Amitryptiline, Duloxetine,Venlafaxine, Carbamazepine, Tramadol, etc) unless they have been at steady dose more than 6 weeks

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: placebo
Drug: placebo
matching placebo for AMRIX
Experimental: cyclobenzaprine ER
Drug: cyclobenzaprine ER (AMRIX)
active drug
Other Names:
  • AMRIX

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Visual Analogue Pain Scale at 8 Weeks Post Treatment
Time Frame: 8 weeks
Change in baseline subjective pain based on a 10 point scale (1= no pain, 10 = severe pain) from baseline (T=Zero, prior to drug/placebo treatment) to week 8
8 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Brief Fatigue Inventory at 8 Weeks Post Treatment
Time Frame: baseline to 8 weeks
Change in baseline subjective fatigue based on this scale (1= no fatigue, 10 = severe fatigue) from baseline (T=Zero, prior to drug/placebo treatment) to week 8
baseline to 8 weeks
Fibromyalgia Impact Questionnaire Scores at 8 Weeks Post Treatment
Time Frame: from baseline to 8 weeks
Change in baseline subjective fibromyalgia symptoms based on a 100 point scale (0 = no fibromyalgia or minimum score, 100 = severe fibromyalgia and maximal score) from baseline (T=Zero, prior to drug/placebo treatment) to week 8
from baseline to 8 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

State University of New York - Upstate Medical University

Collaborators

Cephalon

Investigators

  • Principal Investigator: thomas l schwartz, md, SUNY Upstate

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

June 1, 2009

Primary Completion (Actual)

March 1, 2013

Study Completion (Actual)

March 1, 2013

Study Registration Dates

First Submitted

June 29, 2009

First Submitted That Met QC Criteria

December 29, 2009

First Posted (Estimate)

December 31, 2009

Study Record Updates

Last Update Posted (Actual)

October 6, 2021

Last Update Submitted That Met QC Criteria

October 5, 2021

Last Verified

October 1, 2021

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • amrixfm001

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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