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Comparison of the Efficacy of Duloxetine With Placebo in Patients With Chronic Low Back Pain With a Radicular Component

Phase 4
Completed
Conditions
Chronic Low Back Pain
Interventions
Registration Number
NCT01166048
Lead Sponsor
Medical University of Vienna
Brief Summary

Objective:

The objective of this study is to compare the efficacy of duloxetine in the treatment of patients with chronic low back pain with a radicular component to placebo.

Study hypothesis:

Duloxetine is a new substance now in use for the treatment of neuropathic pain. It has proven its efficacy in diabetic peripheral neuropathy and fibromyalgia in several trials. The investigators therefore hypothesize that duloxetine will be efficacious in patients with chronic low back pain and a radicular component.

Study Rationale:

Chronic low back pain is an extremely common diagnosis. However, therapeutic options for the condition are limited and therapy remains difficult. Duloxetine has proven its efficacy in patients with neuropathic pain and may also be useful in chronic low back pain. If the investigators are able to show a benefit for patients in the duloxetine arm, the substance may constitute a further treatment alternative in chronic low back pain.

Study Design:

Prospective, randomized, double-blind placebo-controlled cross over study. Patients will be administered duloxetine for 4 weeks followed by a 2 week wash-out phase after which they will be medicated with placebo for 4 weeks. A second group of patients will receive the medication in reversed order. The primary study endpoint is constituted the weekly mean of VAS-Score in the last week of each treatment period. Secondary endpoints are defined as use of rescue medication, Beck Depression Inventory score, Health related Quality of Life SF-36 score and side effects/adverse events.

Detailed Description

Not available

Recruitment & Eligibility

Status
COMPLETED
Sex
All
Target Recruitment
41
Inclusion Criteria
  • Low back pain ( below L1)
  • Chronic pain, >6 months
  • Visual Analogue Scale (VAS) ≥ 5
  • Back pain with radicular component defined as pain with a burning, tingling sensation within the anatomic distribution of the nerve root and diagnosed by painDETECT questionnaire
  • Failed back surgery
Exclusion Criteria
  • Current mood disorder (dysthymia, bipolar mood disorder)

  • Major Depression > 12 months (Beck Depression Inventory Score ≥ 18)

  • History of a psychoactive substance use disorder within the preceding 12 months

  • Major coexisting medical illness (e.g. severe heart failure, pulmonary hypertension, renal insufficiency)

  • Glaucoma

  • Acute myocardial infarction

  • uncontrolled hypertension

  • Prostate hyperplasia

  • History of convulsion

  • Pregnancy; women of childbearing age will be required to use contraceptives during the duration of the study. Furthermore a pregnancy test will be performed prior to the beginning of the study and once a month during the study period.

  • Participation in a clinical trial in the 3 weeks preceding the study

  • Allergy to study medication

  • Use of the following medication:

    • opioids except for tramadol,
    • benzodiazepines other than indicated at low doses for sleep disorders
    • antineuropathic medication including except for that specified in the study protocol
    • muscle relaxants
    • antidepressants other than indicated at low doses for sleep disorders
    • NSAID, Paracetamol
    • non-selective MAO-Inhibitors
    • Fluvoxamine, Ciprofloxacin, Enoxacin
    • Selective Serotonin-reuptake Inhibitors (SSRI)

if tapering of these drugs is impossible before inclusion.

  • Impaired kidney function (Creatinine > 1.5mg/dl)
  • Impaired hepatic function (GOT, GPT >2 fold standard levels)
  • Patients who are not able to understand the study measures and are not able to complete pain assessment forms.

Study & Design

Study Type
INTERVENTIONAL
Study Design
CROSSOVER
Arm && Interventions
GroupInterventionDescription
Milk powder pillDuloxetinePatients will receive 2 placebo pills per day for a period of 4 weeks.
DuloxetineDuloxetineIn the experimental arm of the study patients will receive duloxetine, which will be titrated up to a dosage of 120mg over a period of two weeks and continued at this dosage for two weeks.
Primary Outcome Measures
NameTimeMethod
Weekly mean pain intensity in study phase I (Visual analogue score, units 1-10)Week 4 of study period

Operationally a VAS is a horizontal line, 100 mm in length, anchored by word descriptors at each end (left= no pain, right=worst imaginable pain).The patient marks the current subjective pain intensity on the scale. This is converted to a numeric value by measurement from the left side of the scale. (Units 1-10)

Weekly mean pain intensity in study phase II (Visual analogue score, units 1-10)Week 10 of study period
Secondary Outcome Measures
NameTimeMethod
Health related Quality of Life SF-36 score in phase I of study periodHealth related Quality of Life SF-36 score at week 4 of study period.

Subjects will be asked to fill out the Health related Quality of Life SF-36 questionnaire at screening and at the end of each treatment period (placebo and verum)

Use of rescue medication in phase II of study periodUse of rescue medication in week 10 of study period.
painDetect score in phase II of study periodpainDetect score at week 10 of study period.
Use of rescue medication in study phase IUse of rescue medication in week 4 of study period

Patients will be allowed Metamizol (500mg up to 3g per day) and Tramadol drops (20 ggt. up to 6 times per day) as rescue medication. Rescue medication will be recorded daily in a patient diary. Use of rescue medication will be scored as follows: 0=no rescue medication; 1=metamizol; 2=tramadol

Beck Depression Inventory score in phase I of study periodBeck Depression Inventory score at week 4 of study period

Subjects will be asked to perform the Beck Depression Inventory at screening and at week 4.

painDetect score in phase I of study periodpainDetect score at week 4 of study period.

Subjects will be asked to complete the painDetect questionnaire at screening and the end of each treatment period (placebo and verum).

Beck Depression Inventory score in phase II of study periodBeck Depression Inventory score at week 10 of study period.
Health related Quality of Life SF-36 score in phase II of study period.Health related Quality of Life SF-36 score at week 10 of study period.

Trial Locations

Locations (1)

Department of Special Anesthesia and Pain Therapy, Medical University of Vienna, AKH Vienna

🇦🇹

Vienna, Austria

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