Restless Legs Syndrome Associated With Fexofenadine Use: A Case Report.

Restless legs syndrome (RLS) is a neurological sensorimotor disorder characterized by an irresistible urge to move the legs, typically worsening at night and leading to sleep disturbance. While first-generation antihistamines are recognized as common pharmacological triggers, second-generation nonsedating antihistamines are rarely implicated. We report the case of a 35-year-old man with allergic rhinitis who developed new-onset RLS after 1 month of treatment with fexofenadine 180 mg daily. His symptoms included an uncomfortable urge to move his legs, particularly in the evening and at night, which interfered significantly with sleep quality. Clinical examination and laboratory studies, including renal function and iron indices, were unremarkable. Despite several medical consultations, the symptoms persisted until fexofenadine was discontinued. Remarkably, his symptoms resolved completely within days of withdrawal without pharmacologic intervention and did not recur on follow-up. This case highlights a rare but clinically relevant association between fexofenadine and RLS. Although fexofenadine is classified as a peripherally selective, nonsedating antihistamine, this report underscores that even second-generation agents may contribute to RLS in susceptible individuals. Recognition of this potential adverse effect is important, as prompt discontinuation of the offending medication alone can result in rapid and complete symptom resolution. Clinicians should therefore maintain vigilance when evaluating patients with new-onset RLS and carefully review medication histories, including use of second-generation antihistamines such as fexofenadine.