Montelukast, A Savior for Your Allergies – Could It Be the Reason for the Headaches and Mood Swings?

Case Presentation A 42–year–old male presented at the outpatient clinic with breathing difficulty, productive cough, and nasal congestion. On examination, vitals were normal, the patient was lethargic, and on chest examination, there was bilateral air entry on both sides of the lung with no abnormal sounds. At the clinic, the patient improved on symptomatic treatment with Ventolin (Salbutamol) and Pulmicort (Budesonide) nebulization. He had a history of allergic rhinitis, which was well controlled on levocetrizine and montelukast for the past 1 year. The patient was stable at the time of discharge and was prescribed xylometazoline hydrochloride nasal spray 1 puff each nostril thrice daily for 3 days only, levocetrizine 5mg once daily for 10 days, and montelukast 10mg once daily for 10 days. The patient mentioned that for the past 2 weeks, he had been getting headaches on/off, feeling restless at times. He was counseled that the following symptoms could be a side effect of montelukast, and a neurology review is recommended. The patient agreed to an outpatient appointment with a neurologist.