Methods for reducing the risk of a thromboembolic event, and a related drug delivery system are provided. In some embodiments, a dose of acetylsalicylic acid can be provided in powder form to a patient using a dry powder inhaler. The dose can be effective to reduce a risk of a thromboembolic event in a patient. A dry powder inhaler used for the method can have a mouthpiece, a reservoir for receiving the dose of acetylsalicylic acid, and an actuation member for making available the dose of acetylsalicylic acid for inhalation by a patient through the mouthpiece.