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Generic Metoprolol Reveals Flaws With FDA’s Approval Process

We've been hearing about problems with generic metoprolol since 2007. They're still coming in. Is brand name Toprol XL now affordable?

We have been writing about problems with generic metoprolol for more than a decade. This beta blocker is prescribed for patients with hypertension and heart problems such as angina pectoris, heart failure, rapid pulse and/or irregular heart rhythms. The drug was originally sold under the brand name Lopressor. A sustained-release formulation, Toprol XL, was introduced in the US by AstraZeneca in 1992. A lot of people take metoprolol. At last count the total was more than 15 million in the US. They expect this very old generic drug to work well, but does it?

The Secret of Sustained-Release Screwups:

What very few physicians, pharmacists or patients realize is that sustained-release formulations are unique. They are designed to gradually release the active pharmaceutical ingredient (API) gradually over time.

We suspect that many health professionals think that when a drug loses its patent the secret sauce is revealed to the generic drug companies so they can duplicate the brand name product exactly. Au contraire.

The way the brand name manufacturer makes its pills is a deep, dark secret. Coca-Cola does not reveal its formula to other soft drink makers and brand name pharmaceutical manufacturers do not share their secrets with generic drug companies. The generic manufacturers must reverse-engineer their copy cats. Sometimes they do pretty well. Other times, not so much.

We learned about this because of the antidepressant Wellbutrin XL 300. This brand name medicine releases its active ingredient, bupropion, gradually over many hours. Even after the patent was lost on bupropion, the brand name manufacturer retained the patent on the special membrane slow-release formulation technology.

The generic manufacturers had to come up with a different kind of formulation. The matrix some companies developed released the active ingredient differently and that led to all sorts of complications. You can read about the scandal we uncovered at this link.

Generic Metoprolol vs. Toprol XL Creates Confusion:

When AstraZeneca developed its brand of metoprolol succinate, it created a unique polymer microencapsulation process to deliver the active drug gradually. The XL in Toprol XL stands for extended release. We suspect that some generic drug manufacturers have had problems coming up with their own gradual release formulation.

In 2007, we started receiving messages from visitors to this website that generic metoprolol was not working as well as Toprol XL had. As more and more complaints poured in, we contacted the FDA about our concerns.

On October 21, 2007, we informed Gary Buehler (then director of the Office of Generic Drugs) and other FDA executives that there was a problem with the generic formulation of this and certain other important medications.

Gary Buehler’s response:

“We are investigating all aspects of this issue.”

FDA Inaction on Generic Metoprolol:

We heard nothing from the agency that year (or in following years) about its investigation into generic metoprolol. Nevertheless, over years we continued to receive complaints from patients who maintained that there were generic metoprolol formulations that were not working the same way the brand name Toprol XL did.

We received this question in the fall of 2022:

Q. I have taken metoprolol succinate ER for many years to control my heart rate. Back in 2007, I had lots of trouble when I was switched from brand name Toprol to the generic. So I went back to the brand name from AstraZeneca or an authorized generic. Fortunately, the VA used the AstraZeneca version in its mail-order pharmacy program. Now it has switched to a generic pill made in China.

This generic form of metoprolol does not work well at all. My heart rate shot up to over 100, so my doctor ordered brand name only and my heart rate is back to normal.

The price is astronomical, though, and it is always a fight with the pharmacy. They prefer to dispense the generic. What do you recommend?

A. Beta blocker heart drugs like metoprolol, atenolol and propranolol have a distinctive action on the heart. They all slow the pulse. The fact that your heart rate jumped to over 100 beats per minute strongly suggests that the generic metoprolol you took was not working.

You have a couple of options. There is a pharmacy in Lakeland, Florida, that carries the authorized generic metoprolol succinate formulation. That means it should be identical to brand name Toprol. You can find it online at www.EaglePharmacy.com. We have no connection with this pharmacy. A cardiologist we trust assured us that this authorized generic (AG) form of metoprolol succinate works the same way as the brand name Toprol XL.

Ooops! The Authorized Generic May No Longer Be Available:

That was then. This is now! As far as we can tell, this option may no longer be viable. Here is a recent message from a reader of our syndicated newspaper column:

Q. I’ve had trouble getting the authorized generic (AG) version of Toprol XL. I read that Melinta started distributing an AG but I’ve had no luck getting it.

I emailed Melinta and a pharmacist responded that they stopped selling the AG version of Toprol XL as of Dec. 31, 2023. He suggested purchasing the brand name if I wanted a high-quality product.

A. Toprol is the brand name for the heart and blood pressure medicine metoprolol. A cardiologist colleague has raised questions about the quality of some generic forms of this beta blocker.

When we checked GoodRx.com, we discovered that brand name Toprol XL is available for about a dollar a pill. That makes it reasonably affordable. Yes, the generic is cheaper, but if you want the brand name, the price hopefully won’t break the bank if you have a coupon from GoodRx. We have no financial relationship with GoodRx, just passing along information. It requires that you bypass your insurance, though.

Another option is to buy brand name Toprol XL from a legitimate Canadian online pharmacy. When we checked by using PharmacyChecker.com we found prices ranging from less than 50 cents per pill to over $1.30 per pill. The variable price depends upon where it is shipped from. Many legit online Canadian pharmacies have partnerships with worldwide pharmacies. Some pills come from Australia, New Zealand, the UK or Mauritius. The origins of the country can impact the price of the brand name product.

To learn more about authorized generic drugs and how to identify reputable Canadian pharmacies, you may wish to read our eGuide to Saving Money on Medicines. The online resource is available under the Health eGuides tab.

More Examples Of Generic Metoprolol Problems:

Roger described a blood pressure problem back on December 9, 2007:

“I had been taking Toprol XL for six years with no problems. When the generic (metoprolol succinate) came out, I was switched to that. All was well for a while but then my blood pressure shot way up. I started having dizziness & numbness on the left side of the face. I also had difficulty breathing and anxiety.

“The pharmacist told me that she has heard a ton of complaints about metoprolol succinate and that it is not the same as Toprol XL. She stated that Toprol XL is a time-release formula & metoprolol succinate is not.

“I had my cardiologist switch me back and I started feeling better right away. By the second day my BP was back to normal.”

Stephanie experienced heart rate complications:

“Generic metoprolol ER is not the same as Toprol XL. My pharmacy gave me generic metoprolol in December and within two weeks I started having irregular heartbeats.”

Nancy also developed arrhythmias on generic metoprolol:

“After taking Toprol XL with good results for three years to control cardiac arrhythmias, I was given a generic substitute three weeks ago when I switched pharmacies.

“After taking the daily dosage for five days, I began having more and more arrhythmias to the point of having to be admitted to the hospital. There were no other differences in my daily life.

“After discharge, I returned to the unused brand name drug (Toprol XL) and have had no further problems.”

Debbie describes a problem with her blood pressure that is quite compelling:

“I have been taking brand name Toprol XL for quite some time without any problems. Last week, I ran out and my doctor phoned in the refill for a generic prescription. I received metoprolol ER.

“I took it for 7 days. This is absolutely NOT the same. I have a blood pressure cuff that records my last 100 readings. During about the first 12 hours after taking it, my blood pressure was way too low. During about the last 12 hours, my blood pressure was much higher than it ever was. I am on my way now to pick up a new prescription for the brand name, at an additional cost to me, of course.”

Linda developed an alarming heart rate:

“I was recently taking Toprol XL for a heart rate problem called SVT and was doing fine. Our drug coverage changed and the mail order drug company sent me the generic metoprolol succinate ER tabs.

“About a week after starting the generic drug I was awakened at 5:00 am with a heart rate of 188. We went to emergency and they got it under control. This happened 3 times within a four week period and finally my husband and I told the doctor the only thing we could think of that had changed was the generic drug.

“She immediately wrote a new prescription for brand name Toprol XL. I never had another problem.

“As I understand it, the generic is immediate release and is in the system for about 6 hours and that the Toprol XL is 24 hour time release. I am 54 years old without a blood pressure problem, but someone elderly could have a real serious BP problem on this generic.”

What Happens When a Pharmacy Switches Manufacturers?

We received this message from a visitor to this website:

Q. I’ve been taking metoprolol for about ten years. For a long time, I took one particular generic and it worked fine. Then the pharmacy switched suppliers. After a few doses, my arrhythmia and rapid heartbeat started to recur.

Now the cardiologist’s office is trying to get my insurance to authorize brand name Toprol XL, so I can take something that will work. Why are we expected to use generics that are low quality? I Googled the maker of my current generic metoprolol. They have had numerous recalls.

We have continued to alert the FDA about serious problems with various generic metoprolol products. For people with hypertension, irregular heart rhythms or hypertrophic cardiomyopathy, having a medication that does not work as anticipated could turn into a life-threatening situation.

Adverse Reports Around Metoprolol

A report from Bloomberg News several years ago noted that the agency had received 3,425 adverse incident reports for the drug including “lack of effectiveness,” as well as “troublesome side effects.” In this Bloomberg report, the FDA made it clear that in initial tests, generic forms of metoprolol succinate dissolved properly. That seemed to suggest the FDA had tested various products and found they had all passed muster. The way a pill dissolves in a test solution provides some indication how well it will dissolve in a human body.

But that all changed on May 14, 2014. Without a lot of fanfare, the FDA noted that the Indian drug company Wockhardt had a problem with its metoprolol. That prompted the recall of 110,000 bottles of 50 mg metoprolol succinate.

Should FDA Revise its Criteria?

Perhaps even more worrisome was an acknowledgment by FDA spokesperson Sandy Walsh that the FDA was rethinking the criteria it has used for decades for approving generic drugs. We were gratified to learn that the agency was rethinking its procedures, but we worry that there could be hundreds of products on pharmacy shelves that may not be working the way physicians, pharmacists and patients expect. And we have seen nothing that indicates the agency has actually modified the generic drug approval process.

A GAO (Government Accountability Office) recommendation in February 2022 encouraged the FDA to make unannounced foreign inspections to really assess quality control. The GAO also recommended evaluating different types of translation services during foreign inspections. In addition, it urged FDA to recruit and train investigators specializing in foreign drug inspections. This all seems obvious to us, but apparently the FDA has been slow to implement these essential practices. It abandoned its efforts to make unannounced inspections.


There was a famous phrase uttered aboard the Apollo 13 moon flight on April 14, 1970: “Okay, Houston, we’ve had a problem here.”

For 25 years, we were among the country’s most stalwart supporters of generic drugs. But for the last 20 years we have been telling the FDA that we have a problem with some generic drugs. We suspect that there are also issues with the FDA’s approval process.

We also suspect that there are serious problems with manufacturing quality, particularly in countries like India and China where the FDA does not have adequate personnel to carry out inspections. COVID-19 made everything worse!

If you would like to read more about the details of our investigation into the generic drug problem in America and the FDA’s inadequate oversight, we offer our eGuide to Saving Money on Medicines.

You will discover the details behind the Budeprion XL 300 debacle and learn what steps you can take to avoid generic drug disasters. Not only will you get details about acquiring authorized generics but you will find out how to save money on brand name drugs purchased from legitimate Canadian online pharmacies.

Please share your own generic drug experience (positive or negative) below. We are especially interested in metoprolol stories, but please let us know about any generic drug you have taken.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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