The antipsychotic agent, Abilify (aripiprazole, Otsuka), is the first Food and Drug Administration approved digital pill — a medication embedded with a sensor that can tell doctors whether, and when, patients take their medicine. The wearable sensor patch is made by Proteus Digital Health.

The approval marks a significant advance in the growing field of digital devices designed to monitor medicine-taking and to address the expensive, longstanding problem that millions of patients do not take drugs as prescribed. Experts estimate that so-called nonadherence or noncompliance to medication costs about $100 billion a year, according to published reports, much of it because patients get sicker and need additional treatment or hospitalization.

Patients who agree to take the digital medication, a version of the antipsychotic Abilify, can sign consent forms allowing their doctors and up to four other people, including family members, to receive electronic data showing the date and time pills are ingested.

A smartphone app will let them block recipients anytime they change their mind. Although voluntary, the technology is still likely to prompt questions about privacy and whether patients might feel pressure to take medication in a form their doctors can monitor.

Other companies are developing digital medication technologies, including another ingestible sensor and visual recognition technology capable of confirming whether a patient has placed a pill on the tongue and has swallowed it.