Side Effects of Rosiglitazone (Avandia)
Rosiglitazone, often referred to by its trade name Avandia, is a PPAR (peroxisome proliferator activated) receptor agonist of the thiazolidinedione (TZD) class. It is commonly used in the treatment of diabetes.
Mechanism of Action
Avandia, like other thiazolidinediones, acts as an agonist at PPARs. Activation of this receptor increases insulin action at target tissues, meaning more glucose is utilized and taken up into the tissues. This counters insulin insensitivity in tissues that may cause symptoms in diabetes.
Common Side Effects
Avandia acts on multiple tissues and is as such associated with a number of side effects. The FDA lists the common side effects that occur in more than 1%:
- Hypertension (high blood pressure)
- Anemia (low red blood cells)
- Hyperglycaemia (high blood glucose concentration)
- ALT elevations (indicative of liver damage)
- Hypoglycaemia (low blood glucose concentration)
- Hypocholesterolemia (low blood cholesterol)
- Upper respiratory tract infection
- Back pain
Less Common Side Effects
The FDA reports other side effects have not been reported in large scale clinical trials. They are hormonal imbalances, increases in waist circumference, hepatitis (inflammation of the liver), dyspnea (difficulty breathing), fractures, pulmonary edema (swelling of the peripheries), and decreases in white blood cell concentration.
How Does Pharmacogenetic Testing Work?
Identifying these polymorphisms can aid clinical decision-making. Physicians may alter the dose of Avandia prescribed given a known allele. Unfortunately, routine genomic screening is not carried out by most health care providers. At MD Labs, we provide a genetic testing service that does just this. Rxight® sequences 18 genes (including CYP genes like CYP2C9) to establish how a patient is likely to react to hundreds of medications (including Avandia).
For instance, polymorphisms in the PPAR gene have been associated with variable blood glucose concentrations in patients taking Avandia. This could cause symptoms such as hyperglycaemia. Concurrently, polymorphisms in the enzymes that metabolize Avandia may cause poor metabolism of the drug, raising blood concentrations and potentially increase the likelihood of developing adverse effects. These enzymes are part of the cytochrome P450 superfamily of enzymes, namely isoenzymes CYP2C8 and CYP2C9.
Understand Your Risk for Side Effects with the Rxight® Genetic Test
Many patients do not suffer side effects when taking Avandia. However, some may experience multiple, severe adverse reactions. This interpatient variability can be explained by differences in patient’s genetics. Pharmacogenetics, or the study of how an individual’s genome interacts with the drugs they are prescribed, shows that polymorphisms in the genes that code for receptors and enzymes that rosiglitazone interacts with, will have an effect on its therapeutic efficacy and the likelihood of a patient developing a side effect.
Contributors to this Article:
Michael Sapko, MD, PhD; and Deborah Kallick, PhD, Medicinal Chemistry
Read more about Rxight® : What is PGx Testing?