Positive Effect of Pregabalin Not Only on Neuropathic Pain in Patients with Spinal Cord Injury

Neuropathic Pain in Spinal Cord Injury

Neuropathic pain in patients with spinal cord injury may be triggered by damage to nerve structures not only at the site of the primary lesion but also above it (compression of a peripheral nerve in chronic cases) or below it. The pain is most often dull, burning, or stabbing. It is poorly localized, can be paroxysmal or continuous, and unlike nociceptive pain, it does not have a protective character. The pharmacological treatment of this pain primarily involves antiepileptics and antidepressants, occasionally also nonsteroidal anti-inflammatory drugs or weak opioids.

Characteristics of Pregabalin

Pregabalin is a derivative of gamma-aminobutyric acid (GABA) that acts on the subunit of the voltage-gated calcium channel, thereby affecting calcium entry into neurons in the central nervous system. Although it is classified among third-generation antiepileptics, its main indication currently is neuropathic pain.

Study Design and Objective 

The efficacy of pregabalin in patients with spinal cord injury was demonstrated in a multicenter randomized placebo-controlled study, in which patients (n = 70) were administered a flexible dose of pregabalin (150–600 mg daily divided into 2 daily doses) or placebo (n = 67). Patients were allowed to continue using their established analgesic medication at a stable dose for the duration of the study.

The primary objective was to determine the pain score calculated as the average of values recorded in the patient's diary during the last 7 days of the study.

Results 

The average pain score at the beginning of the study was 6.54 in the pregabalin group and 6.73 in the placebo group. At the end of the observation period, the pain score was lower in the pregabalin-treated patients than in the placebo group (4.62 vs. 6.27; p < 0.001). The treatment effect was observed as early as the first week of treatment. The average dose of pregabalin after the 3-week titration phase reached 460 mg daily.

Significantly better outcomes were achieved by treated patients in the evaluation of pain using the short form McGill Pain Questionnaire (SF-MPQ), in sleep quality assessment, and in anxiety evaluation. A higher percentage of patients in the pregabalin group also reported a response to therapy and overall improvement in condition. The most common side effects were mild to moderately significant and usually transient, mainly feelings of instability and drowsiness.

Conclusion

This study demonstrated that pregabalin at a dose of 150–600 mg daily not only provides relief from neuropathic pain in patients with spinal cord injury but also improves sleep quality, anxiety, and overall condition.

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Sources:
Siddall P. J., Cousins M. J., Otte A. et al. Pregabalin in central neuropathic pain associated with spinal cord injury: a placebo-controlled trial. Neurology 2006; 67 (10): 1792–1800, doi: 10.1212/01.wnl.0000244422.45278.ff.

Hyšperská V., Kříž J. Diagnosis and treatment of pain in patients after spinal cord injury – our experience. Neurology for Practice 2009; 10 (3): 153–159.