The most common side effects of pioglitazone alone or in combination with sulfonylureas, metformin, or insulin are:
- upper respiratory tract infection,
- muscle aches,
- tooth disorders,
- hypoglycemia, and
- sore throat.
In addition, dose related fluid accumulation (edema) can occur especially when combined with insulin. Fluid accumulation can worsen or lead to heart failure. Pioglitazone should not be used in patients with heart disease classified by the New York Heart Association (NYHA) as Class III and IV heart failure or symptomatic heart failure. Fluid accumulation also may lead to macular edema, resulting in reduced vision. Pioglitazone also can reduce red blood cells. Pioglitazone has been associated with liver injury. Periodic monitoring of liver-related side effects and liver tests should be conducted in patients taking pioglitazone.