CONCISE REPORT Assessment of the Efficacy of Gabapentin in Carpal Tunnel Syndrome Iltekin Duman, MD, Koray Aydemir, MD, Ahmet Ozgul, MD, and Tunc Alp Kalyon, MD C arpal tunnel syndrome (CTS) is the most common en- trapment neuropathy characterized by pain and numb- ness of first 3 digits. Pain in forearm, elbow, or even shoulder is not unusual as well. In mild or moderate entrapments of the median nerve, conservative measures such as splints, nonsteroidal anti- inflammatory drugs, physical therapy, ergonomic modifica- tions and steroid injections are preferred. Although conserva- tive treatment modalities successfully reduce the symptoms in most patients, they can fail in some cases. Ongoing symptoms despite the conservative measures are considered to be an indication for surgery. Gabapentin is an antiepileptic drug, but has also been reported to have pain-relieving effect on various neuropathic pain conditions like diabetic neuropathy, postherpetic neural- gia, plexopathies, radiculopathies, and various conditions in neurologic and rheumatological practice. 1–10 There are also reports of some cases who had neuralgia due to entrapment neuropathies who were successfully treated with gabapentin. 5,10 These encouraging reports, made us consider if gabapentin could be useful for mild or moderate cases of CTS, which were refractory to the other conservative measures or unwill- ing for the surgical procedure. So, we conducted the current study to investigate the efficacy of gabapentin in CTS. METHODS This was a prospective clinical trial with 3 months follow-up. Twenty-one patients who were diagnosed as CTS enrolled. Diagnosis was made by physical examination (Tinel and Phalen signs, compression test) and by electrodiagnostic testing. The patients who had thenar atrophy or were treated with steroid injection in last 3 months were excluded. Patients who were pregnant or lactating, patients who had known hypersensitivity to gabapentin, renal insufficiency, and hema- tological disease were excluded. The study was approved by our Institutional Local Ethics Committee and informed con- sent was obtained from each patient. Initial gabapentin dosage was 600 mg/d in 2 divided doses. This dosage was increased, if necessary, gradually every week by 300 mg until a satisfactory pain level, that was approximately half of the initial visual analog scale (VAS) score, was reached. After this level, the dosage was main- tained throughout the study. If intolerance or any side effect developed the dosage was first maintained for 3 days at that level. If side effects persisted the dosage was decreased 300 mg for another 3 days until side effects were relieved. If they persisted, the drug was ceased and the patient was excluded. Clinical examination tests were performed at baseline and weekly for the first month and monthly for remaining of the study period. However, only the values obtained at baseline, at second week, at first, second, and third months, were taken into account for statistical analyses. While per- forming the Phalen and compression tests, before beginning to test, patients were asked to declare when numbness oc- curred. The time was measured from the beginning of the maneuver to the onset of symptoms, in seconds. The test was applied 2 times and mean of the 2 measurements was used in statistical analyses. The values longer than 60 seconds were accepted as negative. On weekly in first month and then monthly visits during the study, in addition to these clinical tests, VAS scores for the intense of pain, for the severity of numbness and for the quality of sleep, were obtained. Scores of the patients for the last week were obtained using 100 mm VAS, which rated patients’ pain from “no pain” to “worst possible pain,” numb- ness from “no numbness” to “the most disturbing numbness they imagined” and quality of sleep from “sound sleep” to “could not sleep until morning.” Patients were asked to sign on the VAS scale that corresponded their pain, numbness, and quality of sleep for the last week. Satisfaction based on patients’ global assessments (no change, mildly improved, moderately improved, significantly improved, almost totally resolved, resolved) was also ob- tained at each visit. Moreover, each patient was given the self-administered questionnaire of Symptom Severity Scale (SSS) and Func- tional Status Scale (FSS) with 2-week intervals for the first month and monthly for the remaining of study. SSS consists of 11 questions with multiple choice responses, scored from 1 point (mildest) to 5 points (most severe). FSS consists of 7 questions with multiple choice responses again, rated from 1 (no difficulty with the activity) to 5 points (cannot perform the activity at all). The overall scores were calculated as the From the Department of Physical Medicine and Rehabilitation, Gulhane Military Medical Academy, Etlik-Ankara/Turkey. No grant, funding, or any kind of support was taken from any organization for this study. Reprints: Dr. Iltekin Duman, Department of Physical Medicine and Reha- bilitation, Gulhane Military Medical Academy, 06018 Etlik-Ankara/ Turkey. E-mail: iltekinduman@yahoo.com. Copyright © 2008 by Lippincott Williams & Wilkins ISSN: 1076-1608/08/1403-0175 DOI: 10.1097/RHU.0b013e318177a62a JCR: Journal of Clinical Rheumatology • Volume 14, Number 3, June 2008 175