This disclosure relates to preventing over-delivery of a drug and related systems and methods. In certain aspects, a method is performed by a data processing apparatus. The method includes receiving, from a drug delivery device, information pertaining to a desired amount of fluid to be delivered by the drug delivery device and receiving information pertaining to a delivered amount of a fluid that has been delivered by the drug delivery device. The method also includes determining that the delivered amount satisfies a predetermined threshold amount and in response to the determination, detecting whether an initial amount of fluid provided to the drug delivery device corresponds to the desired amount of fluid to be delivered.
