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Byetta & Bydureon Side Effects

Byetta and Bydureon are medications used to help treat Type 2 diabetes. But these drugs, containing the active ingredient exenatide, are also linked to very serious side effects and complications that can even include the development of cancer. Clinical research and post-marketing studies have found an increased risk of thyroid cancer, inflammation of the pancreas and the development of pancreatic cancer in patients using Byetta and Bydureon.

Although Byetta and Bydureon have been approved to assist users in the treatment of Type 2 diabetes, these drugs have also been linked to deadly side effects, such as cancer.

Patients taking these drugs are also at an increased risk of developing pancreatitis, a very serious and potentially deadly condition of the organ that works to aid in digestion and the control of blood sugar levels.

Byetta and Bydureon drug labeling also warns patients of the risks of the following conditions:
  • Hypoglycemia (abnormally low level of blood sugar in the body)
  • Renal (kidney) impairment
  • Gastrointestinal disease, such as gastroparesis (a disorder that occurs when the stomach takes too long to empty food)
  • Immunogenicity – patients may develop antibodies to the active ingredient (exenatide)
  • Hypersensitivity (allergic reaction) – including anaphylaxis, which can be deadly

Thyroid Tumors (Cancer Risk)

Clinical study results linked Byetta exposure to thyroid cancer. This risk is especially seen with higher doses of the drug and when used for prolonged periods of time.

Illustration of the thyroid
The thyroid gland is located in the front of the neck.

One study conducted by Michael Elashoff and colleagues at the University of California, Los Angeles and published in Gastroenterology revealed that people who used Byetta were almost five times more likely to develop thyroid cancer than those who took another diabetes medication, Avandia (rosiglitazone).

A review conducted by doctors at National Taiwan University College of Medicine and published in Experimental Diabetes Research found Byetta increased the number of cancerous cells in the thyroids of mice. The U.S. Food and Drug Administration’s adverse-event database also shows an increased risk of thyroid cancer associated with the drug.

According to tests of lab rats, the risk involved the gland’s C cells, resulting in malignant thyroid C-cell carcinomas. This includes medullary thyroid carcinoma (MTC). The increased risk was notably observed in females.

What is the thyroid?
The thyroid is a butterfly-shaped gland that is located in the lower front of the neck, just above the collarbone. It makes hormones necessary for regulating the body’s metabolism, including body temperature, how fast calories burn and how fast the heart beats.

Medullary Thyroid Carcinoma (MTC)

Medullary thyroid carcinomas (MTCs) are moderately malignant tumors affecting the C cells of the thyroid gland that can infiltrate nearby tissues in the neck and spread to other organs in the body as well, such as the lungs and the liver.

A person is more likely to develop MTC if they have a family history of MTC or multiple endocrine neoplasia (MEN). Drug labeling warns against the use of Byetta and Bydureon in these patients.

Signs & Symptoms of Medullary Carcinoma

Most patients with thyroid cancer in its early stages have no symptoms of the disease.

MTC typically begins with a small lump in the thyroid gland and may be accompanied by or followed with lymph node swelling in the neck. MTC can also cause enlargement of one or both thyroid lobes. Sometimes, extensive enlargement involves the entire thyroid gland.

This swelling and enlargement often results in other signs and symptoms of the cancer including:
  • Problems swallowing
  • Neck pain
  • Hoarseness
  • Breathing problems due to narrowed airways
  • Cough
  • Coughing up blood
  • Facial flushing due to overproduction of hormones
  • Diarrhea due to elevated calcitonin levels
  • Weight loss and fatigue

Diagnosis & Treatment of Medullary Carcinoma

Blood testing, an ultrasound of the thyroid and a thyroid biopsy are all methods used to diagnose MTC. Treatment typically involves surgery to remove the thyroid gland and surrounding lymph nodes that may have also been affected. A surgeon who specializes in this type of cancer is important, as MTC is not a common tumor.

Clinical trials are being done to discover new treatments for MTC, according to the National Institutes of Health (NIH). Currently, chemotherapy and radiation do not work well for the cancer. Although, radiation may be used in some patients after surgery.

About 86 percent of patients with MTC live at least five years after diagnosis. The 10-year survival rate is about 20 percent lower.

Pancreatitis & Risk of Pancreatic Cancer

Pancreatitis is a medical condition that causes the pancreas to become inflamed and swell. Severe cases can lead to hospitalization and even death – with a mortality rate of 10 to 30 percent. According to data gathered from the FDA and compiled by the Institute of Safe Medication Practices, there were more than 400 reports of acute and chronic pancreatitis in 2011 resulting from exenatide.

Pancreatitis Reports

In a 2011 study published in Gastroenterology, researchers found people who took Byetta were six times more likely to report pancreatitis. The results were consistent with animal studies that also revealed an increased risk.

Patients taking Byetta or Bydureon are almost 50 percent more likely to develop pancreatitis than those taking other diabetes medications.

As a result of the increasing reports of pancreatitis in users of Byetta, the FDA required the manufacturer to conduct more post-market studies on the drug in 2009. The FDA issued an updated safety communication in 2013, saying it was still investigating the drugs’ link to pancreatitis and cancer.

Pancreatic Cancer

Pancreatic cancer is a cancer with a low survival rate because more than 80 percent of cases are diagnosed after tumors spread to other organs. Long-term survival rates are exceedingly low: about 95 percent of people succumb to the disease within five years.

Illustration of the pancreas
The pancreas is located behind the stomach.

The active ingredient of the diabetes drug is linked to an increase in pancreatic cancer. The same 2011 study published in Gastroenterology revealed that there was an almost three-fold increase in reported cases of pancreatic cancer in users of Byetta.

What is the pancreas?
The pancreas is a long, flattened glandular organ that is located deep in the belly. It is both a part of the digestive system and the endocrine system. The pancreas produces chemicals called enzymes, as well as the hormones insulin and glucagon. It is important to digestion and the control of blood sugar levels in the body.

Because of its “hidden” location within the body, tumors of the pancreas are rarely felt by pressing on the abdomen. Most problems with the pancreas, including pancreatic cancer, are not detected until the condition begins to interfere with the function of the pancreas and other nearby organs, such as the stomach, duodenum (first section of the small intestine), liver and gallbladder.

Signs & Symptoms of Pancreatitis

Most of the time, the enzymes produced by the pancreas, are only active after they have reached the small intestine to carry out their role in the digestion of food. But when these enzymes become active inside the pancreas, they begin to eat away at, or digest, the tissue in the organ. This is turn causes swelling and bleeding in the mixed gland and ultimately results in damage to the pancreas and its blood vessels.

Pancreatitis triggers pain in the upper abdomen that can spread to the back. The pain can surface in various ways, sometimes being felt as mild at first, and often becoming worse after eating.

Other signs and symptoms of pancreatitis might include:
  • Swollen and tender abdomen
  • Gas and/or abdominal fullness
  • Nausea and vomiting
  • Hiccups
  • Indigestion
  • Fever
  • Rapid pulse
  • Mild yellowing of the skin and whites of the eyes (jaundice)
  • Skin rash or sores (lesions)

Pancreatic cancer has a lot of the same symptoms but can also include:
  • Diarrhea
  • Dark urine and clay-colored stools
  • Fatigue and weakness
  • Sudden increase in blood sugar levels (diabetes)
  • Loss of appetite and weight loss

Diagnosis & Treatment of Pancreatitis

A physical exam can reveal abdominal tenderness or a lump that may be associated with a diagnosis of pancreatitis.

Generally, a treating physician who suspects pancreatitis will also check the patient’s following vitals:
The patient will usually have a fever.
Blood pressure
Will typically be low.
Heart rate
Commonly it will be rapid; fast.
Breathing (respiratory) rate
Typically it will be rapid.

In addition to the physical exam and retrieving a patient’s medical history, a doctor will typically perform a blood test for digestive enzymes (amylase and lipase) of the pancreas. In a patient with pancreatitis, the levels of these enzymes are often elevated by about three times the normal level.

Abdominal imaging, such as CT scan, MRI or ultrasound, can also be used where blood tests are unavailable or inconclusive.

Treatment Options

Treatment for pancreatitis often involves a hospital stay along with the following:
  • Pain medicines
  • Fluids given through a vein (IV)
  • Stopping food or fluid by mouth to limit the organ’s activity
  • Antioxidant therapies
  • Treatment of underlying conditions

In more severe cases, or when cancer is present, surgery may be needed to remove dead or infected pancreatic tissue or tumors. In most patients with pancreatic cancer, the tumor has already spread and cannot be completely removed after diagnosis. In such cases, a cure is not possible.

Pancreatitis Complications

Most cases of pancreatitis resolve in about a week. However, the condition can sometimes progress to a life-threatening illness.

The death rate is higher in the following instances:
  • Hemorrhagic (severe bleeding) pancreatitis
  • Liver, heart or kidney impairment
  • Necrotizing pancreatitis – where a portion of the pancreatic tissue is no longer viable (capable of working successfully) due to injury; the dead tissue can become a source of infection

Chronic Conditions

Sometimes, even after healing, the condition can return. Patients should avoid smoking, alcoholic drinks and fatty foods even after pancreatitis has improved. Repeat episodes can lead to chronic pancreatitis.

Some complications that can result from pancreatitis might include:
  • Kidney failure
  • Acute respiratory distress syndrome (ARDS) – a type of fluid buildup in the tiny, elastic air sacs (alveoli) in the lungs
  • Buildup of fluid in the abdomen (ascites)
  • Cysts or abscesses in the pancreas
  • Heart failure
  • Low blood pressure

Please seek the advice of a medical professional before making health care decisions.

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Kristin Compton's background is in legal studies. She worked as a paralegal before joining Drugwatch as a writer and researcher. She was also a member of the National Association of Legal Assistants. A mother and longtime patient, she has firsthand experience of the harmful effects prescription drugs can have on women and their children. Some of her qualifications include:

  • Bachelor of Arts in Legal Studies | Pre-Law from University of West Florida
  • Past employment with The Health Law Firm and Kerrigan, Estess, Rankin, McLeod & Thompson LLC
  • Personal experience battling severe food allergies, asthma and high-risk pregnancies
Edited By

10 Cited Research Articles

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