Pioglitazone (Actos) is a prescription drug of the class thiazolidinedione (TZD) with hypoglycemic (antihyperglycemic, antidiabetic) action to treat diabetes. Actos was the tenth-best selling drug in the U.S. in 2008, with sales exceeding $2.4 billion. While pioglitazone does decrease blood sugar levels, studies on the main cardiovascular outcomes has not yielded statistically significant results. Its cardiovascular safety profile compares favorably with rosiglitazone (Avandia), which was withdrawn after concerns about an increased risk of cardiac events. Pioglitazone has been found to be associated with bladder tumors and has been withdrawn in some countries.
Given previous experiences with the related drug troglitazone, acute diseases of the liver are regarded as a contraindication for pioglitazone.
Pioglitazone and all other drugs of its class (thiazolidinediones) are absolutely contraindicated in patients with heart failure.
A press release by GlaxoSmithKline in February 2007 noted that there is a greater incidence of fractures of the upper arms, hands and feet in female diabetics given rosiglitazone compared with those given metformin or glyburide. The information was based on data from the ADOPT trial. Following release of this statement, Takeda Pharmaceutical Company, the developer of pioglitazone (sold as Actos in many markets) admitted that it has similar implications for female patients.
The risk of hypoglycemia is low in the absence of other drugs that lower blood glucose.
Pioglitazone can cause fluid retention and peripheral edema. As a result, it may precipitate congestive heart failure (which worsens with fluid overload in those at risk). It may cause anemia. Mild weight gain is common due to increase in subcutaneous adipose tissue. In studies, patients on pioglitazone had an increased proportion of upper respiratory tract infection, sinusitis, headache, myalgia and tooth problems.
Chronic administration of the drug has led to occasional instances of cholestatic hepatitis, reversible upon drug discontinuation.
On July 30, 2007 an Advisory Committee of the Food and Drug Administration concluded that the use of rosiglitazone for the treatment of type 2 diabetes was associated with a greater risk of "myocardial ischemic events" when compared to placebo, but when compared to other diabetes drugs, there was no increased risk. Pioglitazone is currently being reviewed. A meta-analysis released subsequently showed that pioglitazone reduced the risk of ischemic cardiac events rather than increased the risk, but increased CHF. The PERISCOPE study compared pioglitazone with glimepiride in diabetics; atherosclerotic plaque volume was measured and followed over time. Glimepiride therapy had highly significant progression of plaque volume over time of 0.73 percent. In comparison, pioglitazone had a -0.16 percent regression in plaque volume. This is the first study to show that diabetic therapy slowed progression of atherosclerosis. Therapy with pioglitazone raised HDL, and lowered triglyceride and hsCRP; these are all beneficial effects on risk factors for coronary artery disease; however, to date, no oral anti-diabetic drug has been shown to reduce the risk of cardiovascular complications.
On June 9, 2011 the French Agency for the Safety of Health Products decided to withdraw pioglitazone in regards to high risk of bladder cancer. This suspension was based on the results of an epidemiological study conducted by the French National Health Insurance. According to the results of the epidemiological study, the French agency found that patients, who were taking Actos for a long time to aid in type 2 diabetes mellitus, significantly increased risk of bladder cancer compared with patients who were taking other diabetes medications. On June 10, 2011 Germany's Federal Institute for Drugs and Medical Devices also advised doctors not to prescribe the medication until further investigation of the cancer risk had been conducted.
On June 15, 2011 the U.S. FDA announced that pioglitazone use for more than one year may be associated with an increased risk of bladder cancer, and that the information about this risk will be added to the Warnings and Precautions section of the label for pioglitazone-containing medicines. The patient Medication Guide for these medicines will also be revised to include information on the risk of bladder cancer.
At least one lawsuit has been launched against Takeda Pharmaceuticals alleging wrongful death caused by the drug.
Combination with sulfonylureas or insulin reciprocally exponentiate risk of hypoglycemia. Therapy with pioglitazone increased risk for pregnancy in those taking oral contraception.
Pioglitazone selectively stimulates the nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR-γ) and to a lesser extent PPAR-α. It modulates the transcription of theinsulin-sensitive genes involved in the control of glucose and lipid metabolism in the muscle,adipose tissue, and the liver. As a result, pioglitazone reduces insulin resistance in the liver and peripheral tissues; increases the expense of insulin-dependent glucose; decreases withdrawal of glucose from the liver; reduces quantity of glucose, insulin and glycated hemoglobin in the bloodstream. Although not clinically significant, pioglitazone decreases the level of triglycerides and increases that of high-density lipoproteins (HDL) without changing low-density lipoproteins (LDL) and total cholesterol in patients with disorders of lipid metabolism, although statins are the drug of choice for this.
Pioglitazone as Actos is supplied in oral tablets containing 15, 30 or 45 mg of pioglitazone base. It is also available in combination with metformin as ActoplusMet (tablets containing 15 mg pioglitazone and either 500 or 850 mg of metformin), Competact (tablets containing 15 mg pioglitazone and 850 mg of metformin) or in combination with glimepiride as Duetact (tablets containing 30 mg pioglitazone and either 2 or 4 mg of glimepiride).
Pioglitazone is marketed as trademarks Actos in the USA, Canada, the UK and Germany, Glustin in Europe, Glizone and Pioz in India by Zydus Cadila and USV Limited, respectively and Zactos in Mexico by Takeda Pharmaceuticals. On August 17, 2012 the US FDA announced its approval of the first generic version of Actos.
^R. Baselt, Disposition of Toxic Drugs and Chemicals in Man, 8th edition, Biomedical Publications, Foster City, CA, 2008, pp. 1271-1272.
^Lincoff AM, Wolski K, Nicholls SJ, Nissen SE (2007). "Pioglitazone and risk of cardiovascular events in patients with type 2 diabetes mellitus: a meta-analysis of randomized trials". JAMA298 (10): 1180–8. doi:10.1001/jama.298.10.1180. PMID17848652.