The Effects of Gastroretentive Gabapentin (Gralise®) on Spinal Stenosis Patients with Radicular Pain

Abstract

Background: The health and efficacy profiles of Gralise® in the treatment of pain from spinal stenosis and radicular symptomatology have not been measured. A review of the current literature indicates that no studies exist that evaluate the safety and efficacy profiles of Gralise® in the treatment of pain from spinal stenosis and radicular symptomatology. Objective: Our study is aimed at determining whether Gralise is a safe and effective pharmacotherapy for the pain from spinal stenosis and radicular symptomatology. Study Design: A 4-week prospective open label single arm and single center study of patients with MRI diagnosis of spinal stenosis with radicular pain. Methods: The primary measure of efficacy was a change in average daily pain (ADP) score from baseline to completion of Gralise therapy for 4 weeks. The secondary efficacy endpoints were the patients’ Patients Global Impression of Change Scale (PGIC), the clinician’s Clinical Global Impression of Change Scale (CGI) reports, and the Medical Outcomes Study (MOS) sleep scale of improvement from baseline to completing 4 weeks of Gralise therapy. The safety and tolerability were evaluated by the incidence of adverse events reported while on Gralise therapy. Setting: The study was performed at the Clinical Research Facilities at Tulane Medical Center, New Orleans, Louisiana, in the period from December 1, 2012, to August 30, 2013. Results: Thirty-five patients achieved an efficacy point of one-week Gralise medication treatment. Twenty-seven of 35 (77.2%) patients completed all 5 visits. The PGIC noted a significant positive change in: (1) activity limitations; (2) symptoms; (3) emotions and overall quality of life when related to their condition from first visit as well as improved degree of change when related to their condition from first to last visit. The MOS sleep scale and sleep diaries noted a significant increase of hours slept on average (an increase in over one hour per night — 5.8 hours versus 6.86 hours) from the beginning of the study to the end. The CGI noted a majority of 10 out of 27 with marked significant therapeutic effect with no side effects. The ADP rating from pain intensity scale and pain diaries noted significant improvement of lesser levels of pain experienced (P =.5907 and P =.8547 respectively). No significant adverse effects were noted in the study. Limitations: Variation in degree of spinal stenosis, small sample size. Conclusions: Gralise demonstrated moderate efficacy with reduced pain intensity and increased sleep and was well tolerated in spinal stenosis patients with radicular symptoms. Key words: Spinal stenosis, gabapentin, Gralise®, radicular pain, neuropathic pain