Although originally used as an anticonvulsant, gabapentin which is a γ-aminobutyric acid has become the first-line choice in the treatment of neuropathic pain. It has earned this distinction through its efficacy combined with its low toxicity and minimal side effect profile. Adverse effects most often include drowsiness or dizziness. The literature includes a few cases suggesting an association between gabapentin use and urinary incontinence. This case focuses on a previously unrecorded association between gabapentin and increased urinary frequency, which was dose dependent.

The patient is a 48-year-old Caucasian male being treated for neuropathic pain of his left upper extremity secondary to a Sjogren syndrome-associated C4 spinal lesion. MRI brain and Lumbar spine were unremarkable. His only medication was gabapentin 300 mg TID which was efficacious in relieving his pain; however, he reported sleep disturbance due to an increased frequency of urination without dysuria or urgency. He arose from sleep 2-3 times per night to void. He found this effect to be dose-dependent and it resolved when he decreased his dose to 100 mg TID.

This association along with previous case reports regarding an association between gabapentin use and urinary incontinence reflects a need for further research on the effect of gabapentin on the genitourinary system. It’s been suggested that GABA B receptor activation by gabapentin may cause relaxation of the external urethra sphincter leading to urinary incontinence and overactive bladder. In this case, it has been noted that the urinary frequency was dose-dependent, which may be related to the above phenomenon. When the dose was decreased from 300 mg TID to 100 mg TID, his symptoms were completely resolved. Considering its widespread use, it is imperative to better understand this adverse effect to guide medication management.