The Effects of Milnacipran on Sleep Disturbance in Fibromyalgia

Fibromyalgia is a condition of chronic widespread pain, sleep disturbance and fatigue. Most of the patients with fibromyalgia complain of either non-restorative sleep or complaints of disturbed sleep due to pain. The study aimed at examining the effects of milnacipran on sleep disturbance in patients with fibromyalgia. The study is a randomized, double-blind, placebo controlled, two way crossover polysomnography (PSG) study to explore the effects of milnacipran on sleep disturbance. Patients received either milnacipran 50 mg twice a day (BID) or matching placebo.

The sleep disturbance in fibromyalgia is characterized as non-restorative in nature, and is defined as a feeling of light sleep, independent of duration, and as non-refreshing. As such, these patients wake up in the morning and complain of stiffness and overall aching of the body.

It is well known that reciprocal relationship exists between sleep and pain, with sleep disturbances being an important contributor to morbidity in fibromyalgia. Milnacipran, a selective serotonin norepinephrine receptor inhibitor (SNRI), was approved by the Food and Drug Administration (FDA) for the management of fibromyalgia. Although milnacipran has extensively been studied in fibromyalgia patients, but there is no objective measure, i.e., the use of overnight polysomnography, to determine its effects on sleep.

The study was undertaken to evaluate the effects of milnacipran on PSG determined measures of sleep in patients with fibromyalgia. The study also evaluated the impact of milnacipran on subjective measures of sleep and fibromyalgia symptoms.

Eligibility Criteria:
Inclusion Criteria:

1. Men or women at least 18 years or older
2. Diagnosis of fibromyalgia
3. Clinically significant sleep disturbance, defined as difficulty in maintaining sleep (wake after sleep onset and arousal index) at least three times per week for at least one month
4. Understand and willing to cooperate with the study procedures
5. Maintain a normal sleep schedule, with daytime-awake and nighttime-sleep schedule, with customary bedtime between 9 PM and midnight, and rise time 5 AM and 9 AM
6. Patients who are able to speak, read, and understand English language and able to follow the study protocol, and are able to sign the informed consent

Exclusion Criteria:

1. Subject has any of the following medical conditions:

   Liver disease, blood disorder, autoimmune disease, endocrine, cardiovascular, hypertension, renal, hepatic, gastrointestinal, or neurological disorder, active peptic ulcer or inflammatory bowel disease
2. Significant sleep apnea
3. Periodic leg movement disorder (PLMD) or restless legs syndrome (RLS)
4. Any form of severe psychiatric illness, moderate to severe depression, including significant risk of suicide
5. Patients with uncontrolled glaucoma
6. Inability to discontinue the prohibited medications
7. Female of childbearing potential not using birth control measures; or lactating.
8. History of alcohol, narcotic, benzodiazepines or other substance abuse within the past one year.
9. Patient on prohibited medication will include but not limited to:

   * Anxiolytics, anti-convulsants, antipsychotics, lithium, barbiturates, anti-histamines, monoamine oxidase inhibitors, or medications that affect sleep
   * Any prescription or over the counter stimulants
   * Medications that are contraindicated with the use of milnacipran
10. Excessive caffeine use, defined as a consumption of more than 500 mg of caffeine or other xanthines, smoking \>1/2 a pack/day or alcohol use \>14 units/week
11. History of allergy to milnacipran.