Actos Side Effects and Bladder Cancer Risks
Actos (pioglitazone) is a Type-2 diabetes medication. Its milder, common side effects include headache, muscle pain and a runny or stuffy nose. The drug carries a black box warning for congestive heart failure, and its association with increased bladder cancer risk led to injury lawsuits.
- Last update: July 2, 2025
What Is Actos and How Does It Work?
The FDA first approved Actos (pioglitazone) in 1999 to treat Type-2 diabetes. The drug is manufactured by Takeda Pharmaceuticals and belongs to a class of drugs called thiazolidinediones, also known as TZDs. Avandia is another drug in this class.
- Helping your body respond better to insulin
- Slowing down how much sugar your liver makes
- Helping your muscles use sugar as energy
Actos is an oral medication that doctors can prescribe in different strengths depending on a patient’s needs. If one medication alone doesn’t lower blood sugar enough, medical providers may prescribe Actos along with other Type-2 diabetes medications such as metformin.
Some people may experience serious side effects from Actos, such as bladder cancer. People who developed bladder cancer filed Actos lawsuits against Takeda for failing to warn about the risk. In 2011, the FDA added a warning on the drug’s label about the potential for bladder cancer.
What Are the Most Common Side Effects of Actos?
Common side effects of Actos are typically mild and include headaches and a runny nose. You should tell your doctor if they bother you or don’t go away.
In clinical trials, these side effects happened in five percent or more of people who took Actos. Side effects are more likely with the highest dose of Actos, which is 45 mg.
We’ve listed these side effects with the most common at the top of the list.
- Cold-like symptoms (upper respiratory tract infection)
- Headache
- Sinus infection
- Muscle pain
- Sore throat
The drug’s label also warns of the potential for weight gain with Actos. If you gain weight after taking Actos, be sure to tell your doctor. It could mean your body has excessive fluid buildup, which may be a symptom of heart failure.
If you experience side effects, you can report them to the FDA’s MedWatch Program.
Serious Health Risks Linked to Actos
While Actos can be effective for managing Type 2 diabetes, it carries significant health risks, including heart failure, bladder cancer, bone fractures and liver problems.
- Heart Failure. Actos has a boxed warning — the FDA’s most serious warning — for new or worsening congestive heart failure (CHF). CHF symptoms include rapid weight gain, swelling (edema), trouble breathing and fatigue.
- Bladder Cancer. Long-term use of Actos (especially over 12 months) is associated with an increased risk of bladder cancer. Patients should watch for symptoms such as blood in the urine, pain during urination or increased frequency of urination and report these to their health care provider.
- Bone Fractures. Actos increases the risk of bone fractures, particularly in women. The fractures typically occur in the hand, arm or foot.
- Liver Damage. Rarely, Actos can cause liver damage or failure. Warning signs of liver failure include nausea, vomiting, stomach pain, dark urine, yellowing of the skin or eyes (jaundice) and loss of appetite.
- Macular Edema. Actos may increase the risk of macular edema, a condition where fluid builds up in the eye’s retina, potentially leading to altered vision or vision loss. Make sure to get regular eye exams, especially when using Actos.
- Hypoglycemia (Low Blood Sugar). When used in combination with insulin or other diabetes medications, Actos can cause dangerously low blood sugar. This may result in dizziness, confusion, sweating or even seizures.
- Edema (Fluid Retention). Actos can cause fluid retention, leading to swelling in the feet, ankles or legs. This can be, but is not always, a symptom of heart failure.
If you have any of the symptoms listed above while taking Actos, talk to your doctor right away.
Like most medications, Actos may also cause allergic reactions. These include swelling of the lips, face and mouth. Some of these can be life-threatening. If you have symptoms of an allergic reaction, seek emergency medical care.
Does Actos Cause Bladder Cancer?
The FDA has not said that Actos definitively causes bladder cancer. The agency, however, reviewed data from studies and found that people who used Actos for over a year at higher doses had an increased risk of bladder cancer.
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2010
The FDA found an early signal of bladder cancer risk from a 10-year epidemiological study.
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2011
The FDA adds bladder cancer warning to the Actos label
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2016
After an updated review of Actos, the FDA found more evidence linking it to an increased bladder cancer risk. The agency added more data about the risk to the drug’s label.
While Actos has not been recalled and remains for sale in the U.S., France and Germany removed the drug from their markets in 2011. This removal followed French government-funded studies that found an increase in bladder cancer risk associated with the drug.
Another study published in Cancer Medicine found that clinical trials and observational studies showed Actos may increase the risk of bladder cancer, especially in people who took high doses for longer periods.
What To Do if You Have Symptoms
If you took Actos and have bladder cancer symptoms, such as blood in the urine, pain during urination or increased frequency of urination, make sure you tell your medical provider.
Diagnosing cancer early allows for more treatment options. Your medical provider can run tests such as a urinalysis to detect blood in the urine, which can be the first sign of bladder cancer.
Who Is Most at Risk From Actos Side Effects?
Certain people may be more at risk from Actos side effects. Factors such as medical history, age and gender may increase the likelihood of having side effects.
- Patients With a History of Bladder Cancer. Actos is associated with an increased risk of bladder cancer, especially with use longer than one year or at higher cumulative doses. Individuals with a personal or family history of bladder cancer are at greater risk and should generally avoid this medication.
- Patients With Heart Failure or Risk of Heart Failure. Actos can cause or worsen congestive heart failure.
- Elderly Patients. Older adults are more susceptible to fluid retention, heart failure and bone fractures, all of which are increased risks with Actos use.
- Women. Women, especially postmenopausal women, have a higher risk of bone fractures when taking Actos.
- Patients With Liver Disease. Although rare, Actos can cause liver toxicity.
- Patients Taking Insulin. The risk of heart failure, macular edema and severe hypoglycemia is higher when using Actos in combination with insulin.
Before starting Actos, be sure to tell your medical provider about any medical conditions you have or medications you’re using.
Several Type-2 diabetes medications are alternatives to Actos, and these may be safer for you to take. You can ask your medical provider for more options.
How Actos Side Effects Led to Lawsuits
After the FDA released its 2011 safety warning about the increased risk of bladder cancer with Actos, people began filing lawsuits claiming Takeda didn’t properly warn the public.
Actos had been on the market for 12 years without bladder cancer warnings, and plaintiffs’ lawsuits said Takeda and Eli Lilly (who co-promoted Actos in the U.S. from 1999 to 2006) concealed the risk.
Notable Actos Settlements and Verdicts
Plaintiffs filed thousands of lawsuits over Actos bladder cancer. The litigation led to a $9 billion jury verdict for one man who developed bladder cancer after taking Actos. It was later reduced to $36.8 million.
Ultimately, Takeda offered $2.4 billion to settle about 9,000 lawsuits in 2015. The Actos settlement covered people who were diagnosed with bladder cancer on or before April 28, 2015, and average payments were around $250,000. Payments could decrease or increase depending on the severity of injuries.
You can learn more about the litigation on Drugwatch’s Actos lawsuits page.
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