BackgroundGabapentin is commonly prescribed for the treatment of neuropathic pain, restless leg syndrome, and partial-onset seizures. Although the most frequent side effects of gabapentin are associated with the central nervous system, gabapentin can also affect the cardiovascular system. Case reports and observational studies have showed that gabapentin can be associated with increased risk of atrial fibrillation. However, all the evidence is concentrated in patients older than 65 years old with comorbidities that predispose them to the development of arrhythmias.Case presentationWe describe a case of an African American male in his 20s that presented to our chronic pain clinic with lumbar radiculitis and developed atrial fibrillation 4 days after being started on gabapentin. Laboratory workup did not show significant abnormalities, including normal complete blood count, comprehensive metabolic panel, toxicology screen, and thyroid-stimulating hormone. Transthoracic and transesophageal echocardiography showed a patent foramen ovale with right-to-left shunt. The patient was initially treated with diltiazem for heart rate control and apixaban. Direct current cardioversion with successful conversion to sinus rhythm was performed 24 hours after admission. The patient was then discharged on apixaban and diltiazem. Apixaban was changed to low-dose aspirin 1 month after discharge.ConclusionWith rapidly increasing usage of gabapentin for approved and off-label indications, it is important to identify unintended adverse effects of this drug as they are considered safe alternatives to opioids. New-onset atrial fibrillation could be induced by gabapentin in young individuals.