Pioglitazone

Key facts

• Pioglitazone (sold as Actos) is a thiazolidinedione. It makes your body's cells more sensitive to insulin, lowering blood sugar in type 2 diabetes without directly increasing insulin release.
• You take it once daily, with or without food, and the full blood-sugar effect can take several weeks to appear.
• Pioglitazone causes fluid retention and must be avoided if you have heart failure, since the extra fluid can worsen it. It also carries a caution around a possible increase in bladder cancer risk with long-term use.
• Seek urgent care for sudden swelling, rapid weight gain, or shortness of breath, or for blood in your urine or pain when urinating.

What pioglitazone treats

Pioglitazone treats type 2 diabetes by improving how your cells respond to insulin, particularly useful for people with significant insulin resistance. It's sometimes added when other diabetes medicines alone don't keep blood sugar in range. It does not treat type 1 diabetes.

How pioglitazone works

Pioglitazone activates a receptor inside fat, muscle, and liver cells (PPAR-gamma) that increases their sensitivity to insulin. Cells take up more glucose from the blood, and the liver releases less. This lowers blood sugar without pushing the pancreas to make more insulin, but the receptor also encourages the body to retain fluid, which is the source of its main risks.

Before you take it

• Do not take pioglitazone if you have heart failure or a history of it, since fluid retention from the drug can worsen heart function.
• Tell your prescriber about any history of bladder cancer or visible blood in your urine; pioglitazone is generally avoided in these situations.
• Avoid it if you have significant liver disease, and tell your prescriber if you're pregnant or breastfeeding.
• Combining it with insulin or a sulfonylurea raises the risk of low blood sugar and fluid retention together.

Side effects

Common effects include swelling in the ankles or feet, modest weight gain, headache, and muscle aches.

Stop and seek urgent medical care for any of these:

• Sudden weight gain, swelling, or shortness of breath, which can mean worsening heart failure.
• Yellowing of the skin or eyes, which can signal liver problems.
• Blood in the urine or pain when urinating.
• Signs of a severe allergic reaction: rash, swelling, or trouble breathing.

Safety essentials

• Avoid pioglitazone entirely if you have heart failure; report any new swelling, rapid weight gain, or breathlessness to your prescriber right away, since these can mean the drug needs to be stopped.
• Report any blood in your urine promptly. Pioglitazone carries a bladder-cancer caution with long-term use, and this symptom needs prompt investigation.
• Your prescriber may check liver function periodically, particularly if you notice fatigue, nausea, or yellowing skin.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.