A medical monitoring system increases patient safety and confidence. The system has a disposable injection device with a container holder for holding a container such as a cartridge or a syringe with a liquid drug for subcutaneous injection. The system includes a passive machine-readable tag mounted to a device housing of the injection device and coding or storing drug information about the drug in the container. The system also includes an electronic module or supplemental device releasably attachable to the injection device. The electronic module comprises injection status sensing means for monitoring a status of an injection or for tracking progress of a medication event, as well as a tag reader different from the sensing means for reading drug information from the machine-readable tag. The system includes a drug status signaling or interfacing unit for signaling to a user a drug status based on, or derived from, the drug information.