Delivering drugs to the central nervous system presents unique challenges. But drug developers and researchers have discovered that delivering CNS therapeutic drugs via inhalation mitigates several of these issues. The accessibility and vascular structure of the nose make it an attractive route for delivering both small molecule drugs and biologics across the blood-brain barrier to the CNS. Pulmonary delivery to the deep lung can have favorable pharmacokinetics. And inhaled delivery offers the potential for faster onset of action and less frequent dosing relative to oral drugs.