Various embodiments of a medical module are provided which includes a primary module housing, a secondary module housing, a dosage sensor, a power source, and a microcontroller. The module is configured to be attached to a disposable drug delivery pen or a reusable drug delivery pen so that the module may: determine dosage selected, injection of selected dosage, duration of injection, time of injection, whether the pen has been primed or shaken to thoroughly mix up insulin mixtures, trans-mit information relating to insulin dosage and injection to a data management unit, provide reminders, error warning or messages on improper usage or reusage of needles, track amount of drug remaining on board the pen or duration of usage of pen with re-spect to expiry of the drug on board, or provide an audible alarm for locating misplaced pen and module.
