A method of stimulating ventilatory and/or respiratory drive in a subject in need thereof includes administering to the subject a therapeutically effective amount of a composition comprising a cystine ester or a pharmaceutically acceptable salt thereof. Embodiments described herein relate to compositions and methods of stimulating ventilatory and/or respiratory drive in a subject in need thereof, and particularly relates to compositions and methods of treating breathing diseases and/or disorders associated with impaired ventilatory and/or respiratory drive.
