For months, Amazon has been signaling that it planned to open an Amazon-branded online pharmacy to compete with the likes of CVS, Walgreens and Rite Aid. This week, it did.

For many consumers, this represents greater convenience and the possibility of paying less for prescription drugs.

It also means what little privacy you have left is rapidly disintegrating.

“Most people consider their medical information to be the information they’re most sensitive about,” said Peter Winkelstein, executive director of the Institute for Healthcare Informatics at the University of Buffalo.

“At this point,” he told me, “we have no idea what’s going to happen when you tell Amazon that you need a certain medication. The only thing that seems fair to say is that they’re going to monetize this information any way they can.”

There it is.

Amazon is perhaps the most data-driven company in the history of the world — a business so adept at gathering customer information and crunching numbers, it can suggest with alarming accuracy purchases of things you may not even have known you wanted.

And now we’re going to add to the mix intimate details of our health and well-being, our lifestyles and behavior, even how long we may live.

An Amazon spokeswoman, asking that I not use her name, said Amazon Pharmacy won’t share patient data with other parts of the company. More on that in a moment.

Winkelstein is an Amazon Prime member. I asked if he’d transfer his prescriptions to Amazon Pharmacy in return for greater convenience and possibly lower prices.

He had to think about that for a moment.

“I just don’t know,” Winkelstein finally responded. “I don’t know if it’s worth it.”

It’s a question millions of Amazon customers soon may be wrestling with.

“Amazon doesn’t need a pharmacy to make predictions about your health,” said Anna Lauren Hoffmann, an assistant professor of information and data ethics at the University of Washington.

But running what could easily end up being the world’s largest online pharmacy “does allow them to make decisions, manipulate prices and increase consumer dependency on Amazon in ever-expanding ways,” she told me.

Think about it. If you’re an Amazon customer (and you probably are), particularly if you’re a Prime member (ditto), the company already knows more about you than any consumer-facing company has ever known about its customers.

In my case, Amazon knows what clothes I wear. It knows the personal-hygiene products I prefer and how often I use them.

It knows the books I read, the movies I watch, the music I listen to.

And now, if I choose to take advantage of speedy free shipping and maybe lower costs for prescription drugs, Amazon will know the most sensitive details of my health and everything that entails, including how well I look after myself and any complications I may experience.

“There are lots of potential dangers to consumers besides the ‘creepiness’ factor that firms know everything about us,” said Florencia Marotta-Wurgler, a law professor at New York University who focuses on digital commerce.

She cited a 2015 data breach involving Ashley Madison, a skeevy website that helped users cheat on their spouses. Hackers accessed the personal information of about 32 million registered customers.

A few months ago, some of those customers received “sextortion” e-mails demanding $1,000 in bitcoin if the recipients wanted to keep their identities secret.

“As the Ashley Madison data breach showed, the release of private information can result in high and painful personal costs,” Marotta-Wurgler said.

That doesn’t worry me as much as another eye-opening incident.

In 2012, Target analyzed purchase data to figure out that a teenage girl residing near Minneapolis was pregnant. It sent her coupons for maternity wear and baby items, much to the consternation of her parents, who had no idea their daughter was in a family way.

Amazon has been getting the hang of drug sales since acquiring the online pharmacy PillPack in 2018. However, it has operated PillPack as an independent subsidiary, separate from its other retail offerings.

The new Amazon Pharmacy is integrated with the rest of the company’s online superstore. It offers Prime members the prospect of easier shopping for meds and lower prices for cash purchases that don’t use insurance — an approach already in use at Costco and some other big-box retailers.

One reason Amazon is so wildly successful is because it’s really, really good at making at online purchases easy and hassle-free.

But health care is different. Federal law prevents medical providers from sharing patients’ data with others.

The Amazon spokeswoman said all patient data will stay within the pharmacy and not be accessible by other Amazon divisions.

But there’s a potential loophole in Amazon Pharmacy’s privacy policy, which allows for sharing of information with “business associates,” including “accounting services, consulting services or information technology services.”

There are a lot of unknowns here. Amazon is an information technology company. Will patient info be available to parts of Amazon that allow an online drugstore to function? Can another Amazon division serve as a “consulting service” for the pharmacy?

What if Amazon moves to acquire an insurance company, as CVS Health did with its 2018 purchase of Aetna? Would the retailer use its insights about customers to adjust coverage rates on an individual basis (as it reportedly does with many consumer products)?

“This is why we need a new, comprehensive privacy law in the United States,” said Alan Butler, interim executive director of the Electronic Privacy Information Center.

“Being subject to invasive data collection and profiling should not be treated as a necessary cost of using services online,” he said.

You can try to prevent any one company from knowing too much about you by, say, spreading purchases among multiple retailers. But all that ultimately does is slow the data gathering, not stop it.

In the case of Amazon, some privacy experts say, it may be a case of in for a penny, in for a pound.

“If you already had millions of gold bullion bars stored at Fort Knox, would you mind backing up the truck and unloading another thousand bars there?” asked Merrill Warkentin, a professor of information systems at Mississippi State University.

“I could argue that you could have more risk by diversifying the locations where your sensitive information is stored,” he said.

Fair point. If Amazon already knows everything else about me, what’s the harm in it knowing about my medical status as well?

The answer is we just don’t know. There’s never before been a company like Amazon, and our laws and regulations never anticipated a business this powerful and this diverse, dominating virtually every market it enters.

It’s no coincidence that shortly after Amazon Pharmacy was announced, shares in CVS, Walgreens and other drugstores instantly plunged.

I choose not to live in fear. My initial take is that Amazon has earned my trust, so it’s not unthinkable I’ll now share my medical information with the company.

That said, adulterous Ashley Madison users probably felt secure as well.