Drug delivery systems and methods are disclosed herein. In some embodiments, a drug delivery system can be configured to deliver a drug to a patient in coordination with a physiological parameter of the patient (e.g., the patient's natural cerebrospinal fluid (CSF) pulsation or the patient's heart or respiration rate). In some embodiments, a drug delivery system can be configured to use a combination of infusion and aspiration to control delivery of a drug to a patient. Catheters, controllers, and other components for use in the above systems are also disclosed, as are various methods of using such systems.