Questions Grow Over Serious Problems Linked to GLP-1 Drugs
GLP-1 medicines have become widely used for diabetes and weight loss. They can help control blood sugar and reduce weight, but some patients have reported serious health problems after taking them. Lawsuits now claim that drugmakers did not give doctors and patients enough warning about these risks.
A Sudden Loss of Vision
Todd Engel spent about 40 years operating heavy equipment near warehouses and highways in Maryland. His work included driving forklifts and rubber-tire loaders.
His doctor prescribed a GLP-1 drug for diabetes in early 2023. On New Year's Eve that year, Engel woke up with severe vision loss in his right eye. He described it as being like a dark patch covering his eye. He could not see anything.
A doctor diagnosed him with non-arteritic anterior ischemic optic neuropathy, commonly called NAION. The condition cannot be treated with surgery. It happens when small blood vessels fail to deliver enough blood to the optic nerve, causing sudden vision loss.
When the doctor explained the known risk factors, Engel's wife, Shelley, asked whether the medicine could be involved. She says the doctor told them there was no known connection.
Several months later, a medical study found that diabetic patients taking semaglutide appeared to have higher rates of NAION. Engel and his doctor did not know about the research at the time. He continued taking weekly injections.
About seven months after losing sight in his right eye, Engel lost vision in his left eye as well. He now says he would have stopped taking the medicine if he had known there might be a connection.
Growing Use and Legal Action
More than one in 10 Americans are taking a GLP-1 drug for weight loss, while about one in seven people have used one at some point. The medicines are also prescribed for diabetes and other health conditions.
Engel has filed a lawsuit claiming that the drugmaker failed to warn patients and doctors about the possible risk of NAION. His case is part of two large groups of lawsuits involving claims of serious or life-changing injuries linked to GLP-1 medicines.
The drugmaker has rejected the claims. It has pointed to later research that questioned whether GLP-1 medicines cause NAION and has said the lawsuits lack merit.
The company that makes another GLP-1 medicine containing tirzepatide has also said it will strongly defend itself against similar claims.
What Researchers Know So Far
A study can show that two events happen together, but that does not prove one caused the other. In this case, the research found a possible connection between semaglutide and NAION. More work is needed to determine whether the medicine directly causes the eye condition.
Two medical groups reviewed the findings and warned that the study could not prove the treatment caused NAION. The groups agreed that a possible link deserved more research. They did not advise patients to stop taking GLP-1 drugs.
Patients are being asked to weigh the possible risks against the known benefits of these medicines. Doctors also must consider that diabetes and obesity can raise the risk of many serious health problems on their own.
A Warning System With Limits
A federal health agency keeps a database of reports about possible drug side effects. Patients, doctors and drug companies can submit information to the system. Most reports are voluntary, and the agency does not confirm every case.
Even with those limits, the database can help regulators identify possible safety problems. It may also lead to more research or changes to a drug's warning label.
The database contains more than 1,000 reports of optic neuropathy connected to GLP-1 medicines since 2024. During the same period, there were nearly 190,000 total reports involving these drugs. Many involved less serious problems, such as stomach issues, incorrect doses or redness at the injection site.
The drugmaker has said that NAION and other severe problems were extremely rare during clinical trials. The company continues to gather information about side effects and share it with federal regulators.
The federal agency has started its own study of possible NAION risks. It is reviewing the available information and will decide whether action, including changes to safety warnings, is needed.
Other Serious Health Claims
The lawsuits include 247 people who developed NAION. More than 4,000 other plaintiffs report serious digestive problems, including pancreatitis and gallstones.
The federal database lists 1,928 reports of pancreatitis linked to GLP-1 medicines since 2024. That total includes 135 reports of necrotizing pancreatitis, a severe form that can destroy pancreatic tissue.
Jonathan Orent, a court-appointed attorney involved in the lawsuits, argues that patients and doctors should receive stronger warnings even when a condition is rare. He says clinical trials may not include enough people to identify uncommon problems. Trials also may not reflect the full range of patients who use the medicines in everyday life.
Why It Is Hard to Find the Cause
Diabetes and obesity are complex diseases. They can affect many parts of the body and may increase the risk of pancreatitis, gallstones and other conditions. That makes it difficult to know whether a health problem came from the medicine or from an illness that was already developing.
Mohammed Ali, a diabetes specialist, treated three patients who developed serious problems while using GLP-1 drugs. He did not report the cases to the federal database because he was unsure the medicine caused them.
He said some patients may have had early pancreatitis or gallstones before starting treatment, without knowing it. The timing of a medical problem can raise concerns, but it does not always prove the medicine was responsible.
Online Sales Add More Concern
GLP-1 medicines are also being sold through online platforms, sometimes with little medical supervision. Robert Miller, a pharmacist at a poison-control center in Texas, says more people are calling after experiencing vomiting and other side effects.
Online buyers may not have a doctor monitoring their treatment. They may also lack a clear place to report problems or ask questions. This can make it harder to track possible side effects and identify unsafe use.
For Engel, the consequences have been permanent. He can no longer work or walk along the beach without help. He cannot play ball with his grandchildren, and he cannot see his wife's face.
Shelley Engel believes better warnings could have changed what happened. She says her husband's once-outgoing personality has also changed since he lost his vision.
“This could have been prevented if we had known,” she said.
GLP-1 medicines have become widely used for diabetes and weight loss. They can help control blood sugar and reduce weight, but some patients have reported serious health problems after taking them. Lawsuits now claim that drugmakers did not give doctors and patients enough warning about these risks.
A Sudden Loss of Vision
Todd Engel spent about 40 years operating heavy equipment near warehouses and highways in Maryland. His work included driving forklifts and rubber-tire loaders.
His doctor prescribed a GLP-1 drug for diabetes in early 2023. On New Year's Eve that year, Engel woke up with severe vision loss in his right eye. He described it as being like a dark patch covering his eye. He could not see anything.
A doctor diagnosed him with non-arteritic anterior ischemic optic neuropathy, commonly called NAION. The condition cannot be treated with surgery. It happens when small blood vessels fail to deliver enough blood to the optic nerve, causing sudden vision loss.
When the doctor explained the known risk factors, Engel's wife, Shelley, asked whether the medicine could be involved. She says the doctor told them there was no known connection.
Several months later, a medical study found that diabetic patients taking semaglutide appeared to have higher rates of NAION. Engel and his doctor did not know about the research at the time. He continued taking weekly injections.
About seven months after losing sight in his right eye, Engel lost vision in his left eye as well. He now says he would have stopped taking the medicine if he had known there might be a connection.
Growing Use and Legal Action
More than one in 10 Americans are taking a GLP-1 drug for weight loss, while about one in seven people have used one at some point. The medicines are also prescribed for diabetes and other health conditions.
Engel has filed a lawsuit claiming that the drugmaker failed to warn patients and doctors about the possible risk of NAION. His case is part of two large groups of lawsuits involving claims of serious or life-changing injuries linked to GLP-1 medicines.
The drugmaker has rejected the claims. It has pointed to later research that questioned whether GLP-1 medicines cause NAION and has said the lawsuits lack merit.
The company that makes another GLP-1 medicine containing tirzepatide has also said it will strongly defend itself against similar claims.
What Researchers Know So Far
A study can show that two events happen together, but that does not prove one caused the other. In this case, the research found a possible connection between semaglutide and NAION. More work is needed to determine whether the medicine directly causes the eye condition.
Two medical groups reviewed the findings and warned that the study could not prove the treatment caused NAION. The groups agreed that a possible link deserved more research. They did not advise patients to stop taking GLP-1 drugs.
Patients are being asked to weigh the possible risks against the known benefits of these medicines. Doctors also must consider that diabetes and obesity can raise the risk of many serious health problems on their own.
A Warning System With Limits
A federal health agency keeps a database of reports about possible drug side effects. Patients, doctors and drug companies can submit information to the system. Most reports are voluntary, and the agency does not confirm every case.
Even with those limits, the database can help regulators identify possible safety problems. It may also lead to more research or changes to a drug's warning label.
The database contains more than 1,000 reports of optic neuropathy connected to GLP-1 medicines since 2024. During the same period, there were nearly 190,000 total reports involving these drugs. Many involved less serious problems, such as stomach issues, incorrect doses or redness at the injection site.
The drugmaker has said that NAION and other severe problems were extremely rare during clinical trials. The company continues to gather information about side effects and share it with federal regulators.
The federal agency has started its own study of possible NAION risks. It is reviewing the available information and will decide whether action, including changes to safety warnings, is needed.
Other Serious Health Claims
The lawsuits include 247 people who developed NAION. More than 4,000 other plaintiffs report serious digestive problems, including pancreatitis and gallstones.
The federal database lists 1,928 reports of pancreatitis linked to GLP-1 medicines since 2024. That total includes 135 reports of necrotizing pancreatitis, a severe form that can destroy pancreatic tissue.
Jonathan Orent, a court-appointed attorney involved in the lawsuits, argues that patients and doctors should receive stronger warnings even when a condition is rare. He says clinical trials may not include enough people to identify uncommon problems. Trials also may not reflect the full range of patients who use the medicines in everyday life.
Why It Is Hard to Find the Cause
Diabetes and obesity are complex diseases. They can affect many parts of the body and may increase the risk of pancreatitis, gallstones and other conditions. That makes it difficult to know whether a health problem came from the medicine or from an illness that was already developing.
Mohammed Ali, a diabetes specialist, treated three patients who developed serious problems while using GLP-1 drugs. He did not report the cases to the federal database because he was unsure the medicine caused them.
He said some patients may have had early pancreatitis or gallstones before starting treatment, without knowing it. The timing of a medical problem can raise concerns, but it does not always prove the medicine was responsible.
Online Sales Add More Concern
GLP-1 medicines are also being sold through online platforms, sometimes with little medical supervision. Robert Miller, a pharmacist at a poison-control center in Texas, says more people are calling after experiencing vomiting and other side effects.
Online buyers may not have a doctor monitoring their treatment. They may also lack a clear place to report problems or ask questions. This can make it harder to track possible side effects and identify unsafe use.
For Engel, the consequences have been permanent. He can no longer work or walk along the beach without help. He cannot play ball with his grandchildren, and he cannot see his wife's face.
Shelley Engel believes better warnings could have changed what happened. She says her husband's once-outgoing personality has also changed since he lost his vision.
“This could have been prevented if we had known,” she said.