Effect of L-dopa In Subacute Back Pain Population

Phase 4

Completed

Conditions: Sub-acute Back Pain

Interventions: Drug: Naproxen
Drug: Placebo
Drug: Carbidopa/Levodopa

Registration Number: NCT01951105

Lead Sponsor: Northwestern University

Brief Summary: This study aims to determine if early treatment with Carbidopa/Levodopa and Naproxen in individuals with sub-acute back pain (SBP) is associated with changes in blocking transition to chronic back pain (CBP).

Detailed Description: The transition from acute low back pain to chronic low back pain has been shown to be a result of changes in brain circuitry. Learning mechanisms give rise to the transition from acute to chronic pain and render the pain to become more emotional. The aim of this study is to further explore the idea that persistent pain, following an inciting injury, leads to an aversive learning signal that reorganizes the brain into a chronic pain state. We hypothesize that blocking the emotional/motivational learning response triggered by peripheral nerve injury in a critical time window will decrease the probability of transition to chronic pain. The primary hypothesis to be tested in the study is that early treatment with Carbidopa/Levodopa and Naproxen in individuals with sub-acute back pain (SBP) should decrease related reorganization and block transition to chronic back pain (CBP). This will be done through a 6 month, double-blind, randomized, placebo-controlled, three-arm, parallel-group trial of the pharmacological treatment Carbidopa/Levodopa for individuals (N = 200) with sub-acute back pain (SBP). A baseline MRI scan will be used to determine each subject's pain type and group assignment. Individuals with recovering sub-acute back pain will be observed over 6 months. Individuals with a persisting sub-acute back pain will be randomized to receive either 12 weeks of Carbidopa/Levodopa plus naproxen or placebo plus naproxen. The main outcome measurements will be the results of MRI scans at the baseline and final visit, assessment of back pain by the NRS pain scale, as well as pain assessment through self-reported questionnaires.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 72

Inclusion Criteria

Male or female, over the age of 18 years, (no racial/ethnic restrictions)
Must have a history of low back pain for a minimum of 4 weeks and a maximum of 12 weeks with signs and symptoms of radiculopathy: positive straight leg raising test with dermatomal radiation and/or myotomal weakness and/or reflex asymmetry; pain must radiate into buttock or below
Must have a high risk phenotype for chronification of back pain (evaluated at baseline T1-MRI, DTI-MRI, and fMRI scans)
Must have an average pain score over a 5 day period (average of ~15 measures on smartphone app) immediately preceding the baseline visit of ≥ 5 (on a 0-10 NRS) at the baseline visit
Must be willing to read and able to understand instructions as well as PROs
Must be in generally stable health Must sign an informed consent document after complete explanation of the study documenting that they understand the purpose of the study, procedures to be undertaken, possible benefits, potential risks, and are willing to participate

Exclusion Criteria

Previous (distinct) episodes of back pain onset (more than 3 distinct episodes of back pain lasting for a total of more than 4 weeks) in the previous year
Evidence of rheumatoid arthritis, ankylosing spondylitis, acute vertebral fractures, chronic spinal stenosis, prior back surgery and history of tumor of the spine
Low back pain associated with any systemic signs or symptoms, e.g., fever, chills
Other comorbid chronic pain conditions such as fibromyalgia or neuropathic pain secondary to diabetes or post-herpes zoster
Chronic neurologic conditions, including Parkinson's disease, Alzheimer's disease, and other conditions associated with dementia
Significant other medical disease such as congestive heart failure, coronary or peripheral vascular disease, chronic obstructive lung disease, or malignancy
Diabetes Type I or Type II
History of glaucoma or narrow angle glaucoma
Presence of undiagnosed skin lesions or history of melanoma
Presence of severe cardiovascular or pulmonary disease, bronchial asthma, renal, hepatic or endocrine disease
History of myocardial infarction with residual cardiac arrhythmia
History of gastrointestinal bleeding or peptic ulcer
Diagnosis of current depression (assessed via BDI, total > 28 are excluded) or psychiatric disorder requiring treatment, or such a diagnosis in the previous 6 months
Use of therapeutic doses of antidepressant medications (i.e., tricyclic antidepressants, SSRIs, SNRIs; low doses used only in the evening for sleep will be allowed if dose is not changed)
Current use of recreational drugs or recent history of alcohol abuse (pattern of drinking having social, financial or physical consequences) or drug abuse
Any change in medication for back pain in the last 30 days
High dose opioid prophylaxis, defined as > 50mg morphine equivalent/day
Use of MAOIs, currently or within the past 2 weeks
Prior use of Levodopa
Use of any of the following drugs: bromocryptine, linezolid, metoclopramide, phenothiazines,promethazine/codeine, isoniazid, rifampin, pyrazinamide
Oral iron supplementation
Contraindications to use of study product, based on any of the following:
- Hypersensitivity to Carbidopa/Levodopa or other constituents of the Carbidopa/Levodopa capsules
- Hypersensitivity to lactose or other constituents of the placebo capsules
- Hypersensitivity to Naproxen or other constituents of the Naproxen capsules
- Hypersensitivity to Acetaminophen or other constituents of the Acetaminophen tablets
Currently taking Levodopa or dopaminergic drugs
Involvement in litigation regarding their back pain or having a disability claim or receiving workman's compensation or seeking either as a result of their low back pain
In the judgment of the investigator, unable or unwilling to follow protocol and instructions
Intra-axial implants (e.g. spinal cord stimulators or pumps)
All exclusion criteria for MR safety: any metallic implants, pacemaker, brain or skull abnormalities, tattoos on large body parts, and claustrophobia
Pregnancy or inability to use an effective method of birth control in sexually active men and women while taking the study drug and for one week thereafter. Barrier contraceptives (condoms or diaphragm) with spermicide, intrauterine devices (IUD's), hormonal contraceptives, oral contraceptive pills, surgical sterilization, and complete abstinence are examples of effective methods of contraception.
Following laboratory abnormalities: liver function tests (SGOT/SGPT) greater than twice the upper limit of normal; unexplained anemia (Hgb <9 g/dL); evidence of renal insufficiency (creatinine >upper limit of normal) or any other abnormality that the principal investigator feels puts the subject at risk during the study
History of chronic opioid use for pain management.
Any medical condition that in the investigator's judgment may prevent the individual from completing the study or put the individual at undue risk

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Placebo & Naproxen	Placebo	Individuals identified as having a persisting phenotype (SBPr) will be treated with placebo capsule plus 250mg naproxen tablet three times a day for 12 weeks.
Carbidopa/Levodopa & Naproxen	Carbidopa/Levodopa	Individuals identified as having a persisting phenotype (SBPr) will be treated with Carbidopa/Levodopa on a flexible dose-titration designed intervention based on dose-response TID throughout the 12 week treatment period. Naproxen (250mg) capsules will be administered orally, one capsule TID, throughout the 12 week treatment period.
Placebo & Naproxen	Naproxen	Individuals identified as having a persisting phenotype (SBPr) will be treated with placebo capsule plus 250mg naproxen tablet three times a day for 12 weeks.
Carbidopa/Levodopa & Naproxen	Naproxen	Individuals identified as having a persisting phenotype (SBPr) will be treated with Carbidopa/Levodopa on a flexible dose-titration designed intervention based on dose-response TID throughout the 12 week treatment period. Naproxen (250mg) capsules will be administered orally, one capsule TID, throughout the 12 week treatment period.

Primary Outcome Measures

Name	Time	Method
Number of Participants With 20% Reduction in Pain on the NRS Pain Intensity Scale	6 months	Primary outcome is 20% reduction in pain intensity at p\<0.1 based on pain ratings during 1 week prior to treatment and last week of study participation (at \~6months)

Secondary Outcome Measures

Name	Time	Method
Percent of Residual Pain Stratified by Gender for Individuals Receiving Treatment	6 months	Residual pain is computed based on pain ratings from the week prior to treatment and last week of study participation (at \~6months)