The sensors would allow health care providers to track precisely when patients take their pills, with the goal of improving medication adherence.

The FDA has approved the marketing of an ingestible sensor that can be embedded in pills. The sensor’s maker, Proteus Digital Health, has been working with the agency since 2008 to determine a pathway for its approval as the first member of a new category of medical device.
The sensor, which is approximately the size of a grain of sand, contains trace amounts of magnesium and copper, which produce a slight voltage when they make contact with the stomach fluid. This signal is detected by a patch worn on the patient’s skin, which then relays the information to a mobile phone application that a specific pill has been taken. The patch can also detect and transmit other information such as the patient’s heart rate and temperature.
With the patient’s consent, the system’s information can be made accessible to health care providers so they can monitor when the patient takes their medication, with the goal of improving adherence. So far, the sensor has only been approved for use with inert pills, but the company hopes to have it approved for use with other medications soon. It would most likely be used with medications that are taken for extended periods, such as those for drug-resistant tuberculosis, diabetes, and for the elderly with chronic diseases.
The device was approved by European regulators in 2010, and the company plans to introduce its first product, Helius, to market in the United Kingdom later this year. It will consist of a mobile health app, stick-on patches, and placebo pills with embedded sensors. Patients will be directed to take the placebo pills at the same time that they take their medication.