Case Report Gabapentin-Induced Urinary Incontinence: A Rare Side Effect in Patients with Neuropathic Pain Sibel Kibar, Sibel Demir, Nebahat Sezer, Belma Füsun KöseoLlu, Meltem Dalyan Aras, and Bilge Kesikburun Department of Physical Medicine and Rehabilitation, Ankara Physical Medicine and Rehabilitation Education and Research Hospital, Ankara, Turkey Correspondence should be addressed to Sibel Kibar; sibelkbr@gmail.com Received 11 June 2015; Revised 20 July 2015; Accepted 6 August 2015 Academic Editor: Paola Sandroni Copyright © 2015 Sibel Kibar et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Gabapentin is a irst-line agent for neuropathic pain management and has a favorable safety proile. he literature includes a few cases of gabapentin-induced incontinence, and most of them involved patients with epilepsy who were between the ages of 12 and 43 years. Herein, we present three patients with neuropathic pain due to diferent diagnoses, and, to our knowledge, these are the oldest reported cases of urinary incontinence caused by gabapentin therapy. A 56-year-old female patient who underwent hip arthroplasty developed a sciatic nerve injury and neuropathic pain postoperatively. Ten days ater she began taking gabapentin to relieve her pain, she experienced daily urinary incontinence. In another instance, a 63-year-old female patient was diagnosed with complex regional pain syndrome, and seven days ater the initiation of gabapentin therapy, urinary incontinence developed. In addition, a 66-year-old male patient with neuropathic pain due to cervical disc pathology complained of urinary incontinence ater the onset of gabapentin therapy. Ater discontinuing this drug, the incontinence symptoms resolved in these patients on the seventh, the irst, and the second days, respectively. Physicians who administer gabapentin should inform their patients about the potential risk of gabapentin-induced incontinence and its negative impact on quality of life. 1. Introduction Gabapentin is a structural analogue of gamma aminobutyric acid (GABA) and was originally designed as an anticonvul- sant [1]. Subsequently, gabapentin became a irst-line agent for neuropathic pain management [2]. Gabapentin primarily exerts its efect via selectively interacting with the 2-1 subunit of voltage-dependent calcium channels [2]; however, its precise mechanism of action remains unclear [3], as its efects involve numerous targets requiring further research [2]. Additionally, gabapentin is widely used not only to treat seizures and neuropathic pain but for numerous other indications, including anxiety and sleep disorders, because of its apparent lack of toxicity [4]. Nevertheless, few studies have reported incontinence associated with the use of gabapentin in patients with epilepsy and neuropathic pain [5–7]. Herein, we present 3 patients with urinary incontinence caused by gabapentin therapy for neuropathic pain. 2. Case Reports 2.1. Patient 1. A 56-year-old female underwent hip arthro- plasty to relieve hip pain caused by coxarthrosis. Postoper- atively, a reduction in hip pain was noted, but the patient complained of right leg paresthesia and ankle weakness. Manual muscle testing of the right leg showed that ankle dorsilexion was 4/5 and toe dorsilexion was 3/5. here were L4-L5-S1 paresthesia and allodynia. ENMG indings indicated sciatic nerve injury. Gabapentin 400mg/day p.o. was started and progressively increased to 2400 mg/day. Fol- lowing administration of gabapentin, the patient’s paresthesia was greatly reduced; however, 10 days ater starting the therapy, she experienced daily urge urinary incontinence. Incontinence was mix type urinary incontinence. Neurolog- ical and systemic physical examination, laboratory tests, and urinalysis were normal. Lumbosacral spine magnetic reso- nance imaging (MRI) showed no abnormality. he vaginal Hindawi Publishing Corporation Case Reports in Neurological Medicine Volume 2015, Article ID 341573, 3 pages http://dx.doi.org/10.1155/2015/341573