Most drugs used for fibromyalgia, including two that are FDA approved for the condition, target either serotonin (another neurotransmitter) or both serotonin and norepinephrine. This study demonstrates that targeting only norepinephrine may be effective as well.
Researchers say the drug esreboxetine lowered pain levels by 30 percent or more, and also improved other symptoms such as physical function, difficulty working and depression.
The study says side effects were mostly mild to moderate and included insomnia, constipation, dry mouth, nausea, dizziness, hot flush, headache and heart palpitations. These are consistent with other medicines that alter norepinephrine activity.
Furthermore, results were similar whether participants were taking 4, 8 or 10 mg doses, suggesting that people may benefit from small doses, which minimizes risks.
The company that makes esreboxetine, Pfizer Pharmaceuticals Inc., is currently not producing the drug. However, this study suggests a new avenue of research for treating fibromyalgia.
Is It Safer?
Esreboxetine is classified as a selective norepinephrine reuptake inhibitor. Some researchers theorize that these drugs are less likely to cause side effects than their cousins, which effect serotonin (SSRIs) alone or both serotonin and norepinephrine (SNRIs.)
Studies of fibromyalgia drug Savella (milnacipran) seem to support this theory. This drug impacts norepinephrine more than serotonin, which is unusual for an SNRI.
- Norepinephrine Dysregulation in Fibromyalgia
- Risk of SSRIs/SNRIs for Fibromyalgia
- What is "Reuptake"?