Topiramate in the Treatment of Sciatica

Irritation or damage to lumbar nerve roots referred to as lumbar radiculopathy or sciatica is a very common clinical entity with a lifetime prevalence of 1-3% in the adult population. Lumbar radiculopathy typically causes back pain and sharp, shooting pain in the leg(s). Despite its prevalence and disabling characteristics, sciatica has never been selectively studied in drug trials. We propose to study the anti-epileptic drug topiramate, which combines multiple potential analgesic actions including sodium channel blockade, GABA agonist-like effects and AMPA/kainate glutamate receptor blockade. Patients will include men and women of all ethnic backgrounds between the ages of 18 and 75 who have had signs and symptoms of sciatica for 3 months or more. The design is a double-blind, two period cross-over study comparing topiramate to placebo. Patients will be called twice a week to individually titrate doses of topiramate towards a maximum of 800 mg per day and monitor side effects. The primary outcome measures in this study will be the daily pain scores in the low back, in the leg and combined. Patients' quality of life and activities of daily living will be secondary outcome measures as assessed by the SF 36, Oswestry, and Beck questionnaires. Sixty five patients will be enrolled in this study and the duration of the study will be 17 weeks, including one week baseline, four week escalation, two week maintenance and two week wash out for topiramate and placebo respectively.