Digestible microchips embedded in drugs may soon tell doctors whether a patient is taking their medications as prescribed. These sensors are the first ingestible devices approved by the US Food and Drug Administration (FDA). To some, they signify the beginning of an era in digital medicine.

“About half of all people don’t take medications like they’re supposed to,” says Eric Topol, director of the Scripps Translational Science Institute in La Jolla,California. “This device could be a solution to that problem, so that doctors can know when to rev up a patient’s medication adherence.” Topol is not affiliated with the company that manufactures the device, Proteus Digital Health in Redwood City,California, but he embraces the sensor’s futuristic appeal, saying, “It’s like big brother watching you take your medicine.”

The sand-particle sized sensor consists of a minute silicon chip containing trace amounts of magnesium and copper. When swallowed, it generates a slight voltage in response to digestive juices, which conveys a signal to the surface of a person’s skin where a patch then relays the information to a mobile phone belonging to a healthcare-provider.

Currently, the FDA, and the analogous regulatory agency in Europe have only approved the device based on studies showing its safety and efficacy when implanted in placebo pills. But Proteus hopes to have the device approved within other drugs in the near future. Medicines that must be taken for years, such as those for drug resistant tuberculosis, diabetes, and for the elderly with chronic diseases, are top candidates, says George Savage, co-founder and chief medical officer at the company.

“The point is not for doctors to castigate people, but to understand how people are responding to their treatments,” Savage says. “This way doctors can prescribe a different dose or a different medicine if they learn that it’s not being taken appropriately.”

Proponents of digital medical devices predict that they will provide alternatives to doctor visits, blood tests, MRIs and CAT scans. Other gadgets in the pipeline include implantable devices that wirelessly inject drugs at pre-specified times, and sensors that deliver a person’s electrocardiogram to their smartphone.

In his book published in January, The Creative Destruction of Medicine, Topol says that the 2010s will be known as the era of digital medical devices. “There are so many of these new technologies coming along,” Topol says, “it’s going to be a new frontier for rendering care.”