The Food and Drug Administration has approved its first digital drug: a pill embedded with a sensor that transmits whether someone has taken it.

Although the approval is a big step for digital medicine, there are concerns about privacy, convenience and cost.

The tablet and embedded sensor is called Abilify MyCite. Abilify, made by Japan-based Otsuka Pharmaceutical, is the brand-name version of aripiprazole, an antipsychotic drug used for treating schizophrenia, bipolar disorder and as an add-on treatment for depression in adults.

The tiny sensor, made by a company called Proteus, is about the size of a grain of sand. It's activated when it comes into contact with fluid in the stomach. The sensor detects and records the date and time the pill is ingested.

The sensor transmits that information to a patch worn by the patient. The patch then sends the data to a smartphone application; the data can then be shared with selected family members or caregivers.

That's a lot of moving parts, but the problem it aims to address is a real (and expensive) one: nonadherence, which is the term for patients not following through with prescribed treatment. Nonadherence is a problem for people with many kinds of health conditions, such as hypertension and high cholesterol.

"Being able to track ingestion of medications prescribed for mental illness may be useful for some patients," said Dr. Mitchell Mathis, director of the Division of Psychiatry Products in the FDA's Center for Drug Evaluation and Research. "The FDA supports the development and use of new technology in prescription drugs and is committed to working with companies to understand how technology might benefit patients and prescribers."

In its announcement, the FDA notes that Abilify MyCite's labeling information states the product hasn't been shown to improve patients' compliance with their treatment regimen. It also says that "Abilify MyCite should not be used to track drug ingestion in 'real-time' or during an emergency because detection may be delayed or may not occur."

Some health experts were surprised that the first digital drug to be approved by the FDA is an antipsychotic, because some people who have schizophrenia experience paranoia and delusions that they are being watched.

Taking a pill that transmits data from their body to others might not be desirable to these patients.

"Many of those patients don't take meds because they don't like side effects, or don't think they have an illness, or because they become paranoid about the doctor or the doctor's intentions," Dr. Paul Appelbaum, director of law, ethics and psychiatry at Columbia University's psychiatry department, told The New York Times.

"A system that will monitor their behavior and send signals out of their body and notify their doctor?" Appelbaum said. "You would think that, whether in psychiatry or general medicine, drugs for almost any other condition would be a better place to start than a drug for schizophrenia."

Still, there are upsides to a pill with a built-in sensor, says Dr. Walid Gellad, co-director of the Center for Pharmaceutical Policy and Prescribing at the University of Pittsburgh.

Gellad tells NPR that while Abilify MyCite might not be attractive to patients, it may appeal to caregivers and family members who worry about whether a person has taken his medication. Most of the other current tracking options involve pill bottles that track whether they've been opened, he says.

With this drug, Gellad says, "you will actually know if a person has taken the pill, put in in their mouth, and it's in their stomach."

But he points out that other possible solutions to the nonadherence problem already exist. For instance, there is an injectable version of Abilify, a monthly shot administered by a health care professional.

Then there's the potential cost factor for Abilify MyCite, which doesn't yet have a set price.

The list price for a month's supply of nondigital Abilify pills "is at least $891," according to The Wall Street Journal,which adds that "the smallest vial of the long-acting injectable — introduced in 2013 — has a list price of $1,478."

The FDA approved the first generic versions of Abilify two years ago, and Gellad predicts that "the daily generic is going to be much less expensive than this one with the sensor."

And he warns that there are broader privacy concerns when it comes to sensors that transmit health information.

"We've seen time and time again that stuff that's being transmitted ends up in the hands of people it shouldn't," Gellad says. "There are real concerns about data security."

Copyright 2021 NPR. To see more, visit https://www.npr.org.