Brain Response to Single Dose of Pregabalin in Fibromyalgia

Summary

Fibromyalgia syndrome represents a "spectrum disorder" characterized by widespread chronic pain, fatigue, sleep disturbances, mood and cognitive alterations. The most accepted models explaining the causes of the disease have focused on the reduced pain inhibitory systems activity, that allow low intensity stimuli to be processed easier, and that finally amplify pain stimuli. One of the interventions approved for Fibromyalgia is Pregabalin, which demonstrated to be effective reducing pain. Different studies in animals have shown that it works reducing the liberation of neuronal messengers, which slow the conduction of pain signals. Although studies in humans have confirmed Pregabalin clinical benefits, there are still few studies aiming to explain how it actually works in patients with fibromyalgia, though.

A better understanding of the mechanisms by which Pregabalin reduces pain in patients with fibromyalgia would allow designing new interventions to enhance its clinical effects. Thus, the investigators propose to study in real-time the electrical, vascular and hormonal response of the brain of patients with fibromyalgia who receive a single dose of Pregabalin. The vascular response will be assessed using functional near infrared spectroscopy (fNIRS) neuroimaging techniques. The electrical response will be assessed using Transcranial Magnetic Stimulation (TMS). The hormonal response will be assessed in blood, measuring neurotrophins (Brain Derived Neurotrophic Factor) and inflammatory mediators (Tumor Necrosis Factor). These responses will be studied in consideration of the patients' characteristics that will be assessed using validated scales.

Taken into account the above considerations, a crossover, double-blinded randomized clinical trial is proposed. In the investigators' study, patients and healthy volunteers will be asked to visit the investigators' laboratory in three opportunities: one for a baseline assessment, and the other two to test the effects of either Pregabalin 150 mg PO or Placebo. All participants will eventually receive both, Pregabalin and Placebo. In each visit a brain hemodynamic, electrical, hormonal and clinical evaluation will be performed.

Conditions

• Fibromyalgia

Interventions

DRUG

Pregabalin

Pregabalin 150 mg PO, single dose.

OTHER

Placebo

Pill of same physical characteristics as the one used for the intervention, containing starch only. Administered PO in single dose.

Sponsors & Collaborators

• Conselho Nacional de Desenvolvimento Científico e Tecnológico

  collaborator OTHER_GOV

• Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.

  collaborator OTHER_GOV

• Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul, Brazil

  collaborator OTHER

• Hospital de Clinicas de Porto Alegre

  lead OTHER

Principal Investigators

• Wolnei Caumo, MD, PhD · HCPA

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

QUADRUPLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

FEMALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2014-12-31

Primary Completion

2017-01-31

Completion

2017-01-31