Fibromyalgia: Psychiatric drugs target CNS-linked symptoms
Repeated pain signals in the periphery may sensitize spinal cord neurons, resulting in amplified and prolonged signals traveling to the brain
Lifestyle changes are as important as medications in controlling fibromyalgia symptoms. In addition to exercise, recommend that patients:
- follow a daily routine
- pace activity to avoid exacerbating symptoms
- reduce stress.
BELIEF: ‘A magic pill exists that will resolve all my symptoms and have no side effects’
Clinical evidence: Most medications that have been studied were effective in 30% to 50% of patients and reduced pain scores by 30% to 50%.
Patient education: Explain to the patient with a pain rating of 7 at the first visit that achieving a pain level of 3 to 4 may be possible with treatment. Even with successful treatment, symptoms may flare intermittently. As with any treatment, adverse effects may occur. Discuss these, so the patient is not surprised.
BELIEF: ‘I can’t exercise’
Clinical evidence: Most patients experience more fatigue and pain with physical activity, but exercise is important to maintain physical function.
Patient education: When discussing an exercise program, focus on what the patient can do. Most patients attempt too much, too soon; advise them to start at a tolerable level (such as 2 to 3 minutes of aerobic activity daily for the first week) and gradually increase as tolerated.
BELIEF: ‘You (the psychiatrist) can make me feel better’
Clinical evidence: Psychiatrists can help by prescribing appropriate medications, but much of the burden falls on the patient to maintain a healthy, active lifestyle and to manage stressors in an adaptive manner.
Patient education: A fibromyalgia patient may find relief with a medication, but symptoms may flare if they ‘overdo’ and take on too many physical or emotional stressors. A consistent, healthy routine is ideal.
BELIEF: ‘I will eventually become disabled by fibromyalgia’
Clinical evidence: Despite little long-term research on fibromyalgia patients, most evidence points to a chronic, fluctuating syndrome that does not worsen with age. Factors that may worsen symptoms include uncontrolled comorbid conditions, chronic opiate use, inactivity, and deconditioning.
Patient education: Discourage long-term physical disability; exercise and maintaining an active daily routine helps patients avoid focusing in a nonadaptive manner on their dysfunction and symptoms.
Source: Sharon B. (Shay) Stanford, MD
New direction with medications
Pregabalin is an anticonvulsant that binds to the alpha-2-delta subunits of neurons’ voltage-gated calcium channels. This activity reduces calcium influx at nerve terminals and inhibits release of excitatory neurotransmitters, such as substance P and glutamate.18 In June 2007, pregabalin was the first medication FDA-approved for fibromyalgia.
Two placebo-controlled trials19,20 showed that pregabalin at 150 mg bid, 225 mg bid, or 300 mg bid significantly reduced weekly mean pain scores in fibromyalgia patients. Click here for details of these trials. The most common side effects—dizziness, somnolence, peripheral edema, blurred vision, and weight gain—were regarded as mild to moderate in 87% of patients.21
Although a dosage of 300 mg bid also was studied, the FDA approved pregabalin at dosages of 150 mg bid and 225 mg bid for fibromyalgia.22
Duloxetine is a serotonin/norepinephrine reuptake inhibitor (SNRI) thought to inhibit dorsal horn neurons’ response to peripheral pain signals by increasing serotonin and norepinephrine in the brain and spinal cord. This SNRI was first FDA-approved for diabetic peripheral neuropathic pain and major depressive disorder. Approval for fibromyalgia at 60 mg/d in June 2008 was based on 2 placebo-controlled, double-blind, 12-week trials comprising 874 patients.23,24Click here for detailed findings of these studies and a 6-month fixed-dose trial.25
Milnacipran is an SNRI that was approved for treating fibromyalgia in January 2009 at dosages of 50 mg bid and 100 mg bid. Like other SNRIs, milnacipran is thought to work by inhibiting pain signals through increasing serotonin and norepinephrine in the brain and spinal cord. Milnacipran has a higher selectivity for norepinephrine reuptake compared with duloxetine, which may mean these medications will have different effects in different patients. Although milnacipran is approved as an antidepressant in other countries, the FDA has not approved it for treating depression in the United States.
Click here for details of a 15-week, double-blind, placebo-controlled trial of milnacipran in patients with fibromyalgia. Side effects in clinical trials were similar to those of duloxetine, with nausea, constipation, and increased sweating being most prominent.26
