Pretreatment Identification of Duloxetine Success in Neuropathic Pain Patients

Rambam Health Care Campus51 enrolled

Overview

The purpose of this study is to identify, prior to prescribing, which neuropathic pain patients will benefit from duloxetine more specific the investigators aims are to: * Verify whether presence of chronic pain alters the pain modulation mechanisms, such as DNIC (diffuse noxious inhibitory control) and TS (temporal summation). * Investigate whether anti-neuropathic medications such as duloxetine indeed change the pain modulation profile, and whether this profile change is associated with a reduction of clinical pain.

There is no accepted practice for selecting among recommended medications for the individual neuropathic pain patient. Guidelines published to date provided the evidence for their efficacy, however, data is not available on how to choose the right medication for the right patient in order to avoid long 'trial and error's. We hypothesize that medications affecting specific process of pain modulation will be more efficacious in patients expressing dysfunction of that specific process. Therefore, medications that enhance descending inhibition such as SSNRI will be more efficacious in patients with less-efficient pain inhibition. The latter is assessed by the conditioned pain modulation (CPM) paradigm. Accordingly, the aim of this study is to examine this hypothesis in painful diabetic neuropathy patients, using duloxetine, an SSNRI agent assumed to augment descending pain inhibition by reuptake inhibition of noradrenalin and serotonin in the spinal cord dorsal horn synapses. We expect to find better effect of duloxetine in those patients whose pain inhibition capability is less efficient, as expressed by their baseline CPM. Further, we aim to evaluate whether pro-nocieptive pattern of pain modulation indeed reverses in response to treatment. This will be explored by comparing the CPM responses before and after treatment, and by correlating pain alleviation with the possible changes in CPM.

Study Type

INTERVENTIONAL

Allocation

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Diabetes Painful Neuropathy

Interventions

DuloxetineDRUG

First week of placebo. then, initial dose of 30 mg/d will be given for one week, in order to minimize possible side effects and drop outs, and then a fixed dose of 60 mg/d will be given for additional 4 weeks

Eligibility

Sex: ALLMin age: 18 YearsMax age: 85 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Patients diagnosed as having painful diabetic neuropathy. * Pain is experienced for more than 3 months. * Pain severity is ≥ 4 on a 0-10 scale (last month average). Exclusion Criteria: * Patient already receiving duloxetine or another SNRI/SSRI. * Known hypersensitivity to duloxetine or any of the inactive ingredients. * Treatment with a monoamine oxidase inhibitor (MAOI) within 14 days of randomization or potential need to use an MAOI during the study or within 5 days of discontinuation of study drug. * Uncontrolled narrow-angle glaucoma * Because of the risk of serious ventricular arrhythmias and sudden death potentially associated with elevated plasma levels of thioridazine (Mellaril), Cymbalta and thioridazine should not be co-administered * Inability to perform psychophysical testing, due to language or perceptual barriers.

Locations (1)

Rambam Medical center

Haifa, Israel

Outcomes

Primary Outcomes

Prediction of duloxetine pain relief efficacy by pre-treatment extent of the CPM response

Regression model will assess predictive value of baseline pre-treatment extent of the CPM response and pain relief efficacy of duloxetine treatment.

Time frame: 2 year

Secondary Outcomes

Treatment-related increase in CPM response

We propose that treatment-related increase in CPM response will be correlated with duloxetine pain relief efficacy

Time frame: 2 years

Data from ClinicalTrials.gov

This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.