Drug Groups

approved; investigational

Description

Rosiglitazone is an anti-diabetic drug in the thiazolidinedione class of drugs. It is marketed by the pharmaceutical company GlaxoSmithKline as a stand-alone drug (Avandia) and in combination with metformin (Avandamet) or with glimepiride (Avandaryl).

Like other thiazolidinediones, the mechanism of action of rosiglitazone is by activation of the intracellular receptor class of the peroxisome proliferator-activated receptors (PPARs), specifically PPARγ. Rosiglitazone is a selective ligand of PPARγ, and has no PPARα-binding action.

Apart from its effect on insulin resistance, it appears to have an anti-inflammatory effect: nuclear factor kappa-B (NFκB) levels fall and inhibitor (IκB) levels increase in patients on rosiglitazone.

Recent research has suggested that rosiglitazone may also be of benefit to a subset of patients with Alzheimer's disease not expressing the ApoE4 allele. This is the subject of a clinical trial currently underway.

Indication

For the treatment of Type II diabetes mellitus

Pharmacology

Rosiglitazone, a member of the drug group known as the thiazolidinediones or "insulin sensitizers", is not chemically or functionally related to the alpha-glucosidase inhibitors, the biguanides, or the sulfonylureas. Rosiglitazone targets insulin resistance and, hence, is used alone or with metformine or sulfonylurea to improve glycemic control in patients with type 2 diabetes mellitus.

Toxicity

Side effects include fluid retention, congestive heart failure (CHF), liver disease

Affected Organisms

Biotransformation

Hepatic. Rosiglitazone is extensively metabolized in the liver to inactive metabolites via N-demethylation, hydroxylation, and conjugation with sulfate and glucuronic acid. In vitro data have shown that Cytochrome (CYP) P450 isoenzyme 2C8 (CYP2C8) and to a minor extent CYP2C9 are involved in the hepatic metabolism of rosiglitazone.

Absorption

The absolute bioavailability of rosiglitazone is 99%. Peak plasma concentrations are observed about 1 hour after dosing. Administration of rosiglitazone with food resulted in no change in overall exposure (AUC), but there was an approximately 28% decrease in C_max and a delay in T_max (1.75 hours). These changes are not likely to be clinically significant; therefore, rosiglitazone may be administered with or without food.

Half Life

3-4 hours

Protein Binding

99.8% bound to plasma proteins, primarily albumin.

Elimination

Following oral or intravenous administration of [14C]rosiglitazone maleate, approximately 64% and 23% of the dose was eliminated in the urine and in the feces, respectively.

Distribution

* 6 L

Clearance

* Oral cl=3.03 +/- 0.87 L/hr [1 mg Fasting]
* Oral cl=2.89 +/- 0.71 L/hr [2 mg Fasting]
* Oral cl=2.85 +/- 0.69 L/hr [8 mg Fasting]
* Oral cl=2.97 +/- 0.81 L/hr [8 mg Fed]
* 3.15 L/hr [Population mean]

References

External Links