Reference
Ko GD, Nowacki NB, Arseneau L, et al. Omega-3 fatty acids for neuropathic pain. Clin J Pain 2010;26:168-172.
Design
Uncontrolled case studies
Participants
5 patients with chronic pain resulting from burns, spinal stenosis, carpal tunnel syndrome, fibromyalgia, or cervical disc herniation
Study Medication and Dosage
Combinations of EPA and DHA totaling 2,400–7,200 mg/day depending on pain severity
Primary Outcome Measures
McGill Pain Questionnaire, DN4 neuropathic pain scales, the Pain Detect Questionnaire, grip strength, and tender point algometry
Key Findings
In all cases, significant reductions in pain were reported.
Case 1 involved a patient with C6/C7 disc herniation compressing the right C7 nerve root accompanied by spinal stenosis. A combined EPA+DHA dose of 4,800 mg/day for 8 months led to a 42% increase in grip strength, a 92% increase in triceps extension strength, and a total elimination of pain. Improvement began after 2.5 weeks.
Case 2 involved a patient with thoracic outlet syndrome and fibromyalgia. A combined EPA+DHA dose of 2,400 mg/day for 7 months led to a 43% reduction in pain as measured by the McGill pain questionnaire and a 60% increase in grip strength on the affected side. A 13-month follow-up measurement of the Pain Detect Questionnaire revealed a 70% reduction in pain from baseline and an 80% reduction in DN4 pain scores.
Case 3 involved a patient suffering from an accident-triggered C6/C7 disc protrusion. X-rays also revealed evidence of moderate-to-severe stenosis of the cervical spine. A combined EPA+DHA dose of 4,800 mg/day, later increased to 7,200 mg/day, for a total of 17 months led to a 90% reduction in the Pain Detect Questionnaire score, a 65% reduction in pain as measured by the McGill pain questionnaire, and an 8% increase in grip strength on the affected side.
Case 4 involved a patient with pain from carpal tunnel syndrome. A combined EPA+DHA dose of 3,000 mg per day for 8 months led to a 41% reduction in a global symptom score. The patient improved enough return to a fulltime work schedule without needing surgery.
Case 5 involved a patient with 1st and 2nd degree burns on 30% of the total body surface. A combination of EPA+DHA (1,200 mg per 23 kg body weight) led to 25–53% reduction in pain scores and an unspecified reduction in morphine dosage.
Practice Implications
This is the first published report examining the effects of omega-3 fatty acids on neuropathic pain. A variety of potential mechanisms explaining how EPA and DHA might reduce such pain have been suggested (eg, the blocking of voltage-gated sodium channels) but to date these mechanistic explanations remain hypothetical.
In this column we generally avoid reporting on the findings of case studies. A small number of subjects paired with a lack of placebo control or randomization or blinding of the observer, and a lack of statistical analysis do not add up to adequate scientific support.
However, the findings of case studies can trigger further research and even, as may be the case here, some immediate experimentation on the part of healthcare practitioners.
However, the findings of case studies can trigger further research and even, as may be the case here, some immediate experimentation on the part of healthcare practitioners.
Treatment of patients with the kinds of chronic pain reported in this series of cases can be difficult. The sharp reductions in chronic pain reported here far exceed what would be expected from placebo effect alone and suggest that some readers of this column may, when other therapies fail to produce adequate clinical results, consider therapeutic trials with high-dose EPA+DHA. Further evidence is needed before omega-3 fatty acids can be proven to reduce pain in cases such as those described here.
