Glimepiride, like glyburide and glipizide, is a "second-generation" sulfonylurea agents. Glimepiride is used with diet to lower blood glucose by increasing the secretion of insulin from pancreas and increasing the sensitivity of peripheral tissues to insulin. The mechanism of action of glimepiride in lowering blood glucose appears to be dependent on stimulating the release of insulin from functioning pancreatic beta cells, and increasing sensitivity of peripheral tissues to insulin. Glimepiride likely binds to ATP-sensitive potassium channel receptors on the pancreatic cell surface, reducing potassium conductance and causing depolarization of the membrane. Membrane depolarization stimulates calcium ion influx through voltage-sensitive calcium channels. This increase in intracellular calcium ion concentration induces the secretion of insulin. Glimepiride is used for concomitant use with insulin for the treatment of noninsulin-dependent (type 2) diabetes mellitus. Glimepiride`s original trade name is Amaryl.

Metformin is the most widely used drug to treat type 2 diabetes, and is one of only two oral antidiabetic drugs on the World Health Organization (WHO) list of essential medicines. Metformin is an antihyperglycemic agent which improves glucose tolerance in patients with type 2 diabetes, lowering both basal and postprandial plasma glucose. Metformin decreases hepatic glucose production, decreases intestinal absorption of glucose, and improves insulin sensitivity by increasing peripheral glucose uptake and utilization. However, we still do not completely understand its mechanisms of action. The main effect of this drug from the biguanide family is to acutely decrease hepatic glucose production, mostly through a mild and transient inhibition of the mitochondrial respiratory chain complex I. In addition, the resulting decrease in hepatic energy status activates AMPK (AMP-activated protein kinase), a cellular metabolic sensor, providing a generally accepted mechanism for the action of metformin on hepatic gluconeogenesis. The use of metformin, the most commonly prescribed drug for type 2 diabetes, was repeatedly associated with the decreased risk of the occurrence of various types of cancers, especially of pancreas and colon and hepatocellular carcinoma.

MK-0533 is a novel selective peroxisome proliferator-activated receptor gamma modulator for the treatment of type 2 diabetes mellitus. In comparison with PPARγ full agonists, MK-0533 displayed diminished maximal activity (partial agonism) in cell-based transcription activation assays and attenuated gene signatures in adipose tissue. MK-0533 exhibited comparable efficacy to rosiglitazone and pioglitazone in vivo. However, with regard to the induction of untoward events, MK-0533 displayed no cardiac hypertrophy, attenuated increases in brown adipose tissue, minimal increases in plasma volume, and no increases in extracellular fluid volume in vivo. MK-0533 was teste in phase II clinical trials but future development was discontinued.

Rosiglitazone acts as a highly selective and potent agonist at peroxisome proliferator activated receptors (PPAR) in target tissues for insulin action such as adipose tissue, skeletal muscle, and liver. It is FDA approved for the treatment of as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. Inhibitors of CYP2C8 (e.g., gemfibrozil) may increase rosiglitazone levels; inducers of CYP2C8 (e.g., rifampin) may decrease rosiglitazone levels. Common adverse reactions include edema, weight gain, and headache.