rosiglitazone

Rosiglitazone is an oral drug that reduces the amount of sugar (glucose) in the blood. It is used for treating patients with type 2 diabetes and is in a class of anti-diabetic drugs called thiazolidinediones. The other member of this class is pioglitazone (Actos). Insulin is a hormone produced by the pancreas that is important for controlling the levels of glucose in the blood. Insulin stimulates the cells of the body to remove glucose from the blood and thereby lowers the level of glucose in the blood. Patients with type 2 diabetes cannot make enough insulin or are resistant to the effects of insulin (insulin resistance). As a result, the cells in their bodies do not remove enough glucose from the blood, and the level of glucose rises. Rosiglitazone often is referred to as an "insulin sensitizer" because it attaches to the insulin receptors on cells throughout the body and causes the cells to become more sensitive (more responsive) to insulin and remove more glucose from the blood. At least some insulin must be produced by the pancreas in order for rosiglitazone to work. Rosiglitazone was approved by the FDA in May 1999.

AND PRECAUTIONS The most common side effects seen with rosiglitazone alone or in combination with metformin are:

• upper respiratory tract infection,
• headache,
• back pain,
• hyperglycemia (elevated blood sugar),
• fatigue,
• sinusitis,
• diarrhea, and
• hypoglycemia (low blood sugar).

Rosiglitazone has been shown to cause mild to moderate accumulation of fluid (edema) and can lead to heart failure. Patients who already have heart failure may develop worsening symptoms with rosiglitazone. Therefore, rosiglitazone should not be used by patients with heart failure. Rosiglitazone also has been associated with an increased risk of chest pain and heart attacks. The risk of heart attacks may be greater in those with established heart disease and taking nitrates or individuals receiving insulin.

Other important side effects include:

• anemia with rosiglitazone alone or combined with metformin.
• weight gain, and
• Increased risk of bone fractures in women who received rosiglitazone for 4 to 6 years.

Rosiglitazone may be taken once or twice daily, with or without meals. Daily doses range from 4 to 8 mg either with or without other antidiabetic medications. There is no additional benefit for doses greater than 8 mg per day.

Rifampin decreases concentrations in the blood of rosiglitazone by increasing its breakdown in the liver. Therefore, use of rifampin may decrease the effectiveness of rosiglitazone.

Gemfibrozil (Lopid) increases the concentration of rosiglitazone in the blood by reducing its breakdown in the liver. Therefore, rosiglitazone may increase the side effects of rosiglitazone.

Rosiglitazone should not be combined with nitrates (for example, isosorbide dinitrate [Isordil Titradose, Dilatrate-SR, Isochron]). In clinical trials, the risk of chest pain and heart attacks was greater in individuals on nitrate therapy.

• There are no adequate studies of rosiglitazone in pregnant women. Rosiglitazone crosses the placenta and is detectable in fetal tissue.
• It is unknown if rosiglitazone is secreted in breast milk. Therefore, the safety of rosiglitazone to nursing infants also is unknown.

What preparations of rosiglitazone are available?

Tablets: 2, 4, and 8 mg.

How should I keep rosiglitazone stored?

Tablets should be kept at room temperature, 15 C -30 C (59 F -86 F).