A drug delivery monitoring system comprising a monitor is disclosed that utilizes sound to monitor the occurrence and properties of a drug delivery event. The monitor is affixed to the exterior of a drug delivery device or drug container, and thus does not require disassembly of the drug delivery device and cannot interfere with the operation of the drug delivery device. The monitoring system includes a display device such as a smart phone or tablet computer for analyzing data related to the drug delivery device usage and displaying information to a patient or caregiver before, during, and after a drug delivery event.
