PPARs are transcription factors that reside in the nucleus and become activated by ligands such as thiazolidinediones. Thiazolidinediones enter the cell, bind to the nuclear receptors, and alter the expression of genes. The several PPARs include PPARα, PPARβ/δ, and PPARγ. Thiazolidinediones bind to PPARγ. PPARs are expressed in fat cells, cells of the liver, muscle, heart, and inner wall (endothelium) and smooth muscle of blood vessels. PPARγ is expressed mainly in fat tissue, where it regulates genes involved in fat cell (adipocyte) differentiation, fatty acid uptake and storage, and glucose uptake. It is also found in pancreatic beta cells, vascular endothelium, and macrophages Rosiglitazone is a selective ligand of PPARγ and has no PPARα-binding action. Other drugs bind to PPARα. Rosiglitazone also appears to have an anti-inflammatory effect in addition to its effect on insulin resistance. Nuclear factor kappa-B (NF-κB), a signaling molecule, stimulates the inflammatory pathways. NF-κB inhibitor (IκB) downregulates the inflammatory pathways. When patients take rosiglitazone, NF-κB levels fall and IκB levels increase. History
Rosiglitazone was approved by the US FDA in 1999 and by the EMA in 2000;  the EMA however required two postmarketing studies on longterm adverse effects, one for chronic heart failure and the other for cardiovascular effects. Society and culture
Sales
US sales of the drug were of $2.2 billion in 2006. Sales in 2Q 2007 down 22% compared to 2006. 4Q 2007 sales down to $252 million.Though sales have gone down since 2007 due to safety concerns, Avandia sales for 2009 totalled $1.2 billion worldwide.
Nissens meta analysis was criticized in a 2007 article by George Diamond et al. in the Annals of Internal Medicine. The authors concluded that Nissens analysis had excluded trials with important data on the cardiovascular profile of rosiglitazone, had inappropriately combined trials of greatly differing design, and had inappropriately excluded trials with no cardiovascular events. The authors concluded that no firm conclusion could be drawn regarding whether rosiglitazone increased or decreased cardiovascular risk. Investigators from the Cochrane Collaboration published a meta-analysis of their own on the use of rosiglitazone in Type II diabetes, concluding there was not sufficient evidence to show any health benefit for rosiglitazone. Noting the recent publication by Nissen, they repeated their meta analysis including only the trials included in the Nissen study that dealt with Type II diabetics. (The Nissen study included some trials in people with other disorders.) They did not find a statistically significant increase in cardiovascular events, but noted that all of the cardiovascular endpoints they analyzed showed a non-significant trend toward worse outcomes in the rosiglitazone arms.In July 2007 the FDA held a joint meeting of the Endocrinologic and Metabolic Drugs Advisory Committee and the Drug Safety and Risk Management Advisory Committee. FDA scientist Joy Mele presented a meta analysis examining the cardiovascular risk of rosiglitazone in completed clinical trials. The study found an overall 1.4x increase in risk of cardiovascular ischemic events relative to the control arms.