Low Dose Naltrexone for Treatment of Pain in Patients With Fibromyalgia - Effect Via a Central Mechanism? (LDN-in-FM)

Rigshospitalet

Status and phase: Completed; Phase 4

Conditions: Fibromyalgia

Treatments: Drug: Low dose naltrexone; Drug: Placebo

Study type: Interventional

Funder types: Other

Identifiers

NCT02806440

2015-002972-26

Details and patient eligibility

About

This study evaluates the effect and mechanism of low dose naltrexone for treatment of pain in patients with fibromyalgia. It s a randomised, double-blinded, placebo-controlled, cross-over study.

The study takes place at The Multidisciplinary Pain Center in Grindsted.

Full description

Fibromyalgia syndrome is a prevalent musculoskeletal disorder characterized by pain, profound fatigue, sleep disorder, mood disturbance etc. The prevalence is estimated to be 2-8%.

Treatment of pain in patients with fibromyalgia is often based on opioids. However, opioids may lead to tolerance, addiction and hyperalgesia and alternative treatments are therefore warranted.

Low dose naltrexone (3-5mg) (LDN) has shown promising results in the treatment of pain in patients with fibromyalgia, but there is a need for further research.

At the typical dose of naltrexone, 50 mg, it is an opioid antagonist. However LDN demonstrates analgesic and anti-inflammatory effects, possibly involving an antagonism of microglia in the CNS.

The investigators hypothesize, that LDN has a better pain relieving effect than placebo in in patients with fibromyalgia (FM). The investigators also hypothesize that LDN has a better effect upon experimentally induced pain in FM-patients, compared to placebo. A tentative mechanism is a central facilitation of the endogenous pain inbitory system.

Enrollment: 58 patients

Sex: All

Ages: 18 to 65 years old

Volunteers: No Healthy Volunteers

Inclusion and exclusion criteria

Patients diagnosed with fibromyalgia based on the criteria of American College of Rheumatology.

Inclusion Criteria:

• Widespread pain in patients with fibromyalgia (based on the above criteria)
• Enrolled as a patient in one of the multidisciplinary pain clinics involved in the project
• Inflammatory rheumatic disease (peripheral inflammation, including arthritis), must be excluded
• Women must be treated with a contraceptive measure, if not menopausal

Exclusion Criteria:

• Cancer
• Treatment with opioids (other analgesic treatments in stabile dose 14 days prior to study start are allowed)
• Change in stabile treatment (p.n. paracetamol is allowed, but must be registered)
• Pregnant/breastfeeding
• Does not speak/understand Danish
• Allergy to the ingredient
• Severe liver impairment
• Severe kidney impairment
• Acute hepatitis

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Quadruple Blind

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58 participants in 2 patient groups, including a placebo group

Low dose naltrexone

Active Comparator group

Description:

Low dose naltrexone 4.5 mg/tablet, 1 tablet a day for 21 days

Treatment:

Drug: Low dose naltrexone

Placebo

Placebo Comparator group

Description:

Placebo tablet 1 tablet a day for 21 days

Treatment:

Drug: Placebo