Rosiglitazone maleate is an oral antidiabetic agent which acts primarily by increasing insulin sensitivity. Rosiglitazone maleate is used in the management of type 2 diabetes mellitus (also known as non-insulin-dependent diabetes mellitus (NIDDM) or adult-onset diabetes).

Rosiglitazone maleate improves glycemic control while reducing circulating insulin levels.Pharmacological studies in animal models indicate that rosiglitazone improves sensitivity to insulin in muscle and adipose tissue and inhibits hepatic gluconeogenesis. Rosiglitazone maleate is not chemically or functionally related to the sulfonylureas, the biguanides, or the alpha-glucosidase inhibitors.

Risk Factor - C

Due to its mechanism of action, rosiglitazone maleate is active only in the presence of insulin. Therefore, rosiglitazone maleate should not be used in ... click here to view more

Contraindication: contraindicated in patients with known hypersensitivity to this product or any of its components.

In clinical trials, approximately 4600 patients with type 2 diabetes have been treated with rosiglitazone maleate; 3300 patients were treated for 6 months or longer and 2000 patients were treated for 12 months or longer. There were a small number of patients treated with rosiglitazone maleate who had adverse events of anemia and edema.

Overall, these events were generally mild to moderate in severity and usually did not require discontinuation of treatment with rosiglitazone maleate. In double-blind studies, anemia was reported in 1.9% of patients receiving rosiglitazone maleate compared to 0.7% on placebo, 0.6% on sulfonylureas and 2.2% on metformin. Edema was reported in 4.8% of patients receiving rosiglitazone maleate compared to 1.3% on placebo, 1.0% on sulfonylureas, and 2.2% on metformin. Overall, the types of adverse experiences reported when rosiglitazone maleate was used in combination with metformin were similar to those during monotherapy with rosiglitazone maleate. Reports of anemia (7.1%) were greater in patients treated with a combination of rosiglitazone maleate and metformin compared to monotherapy with rosiglitazone maleate.
Lower pre-treatment hemoglobin/hematocrit levels in patients enrolled in the metformin combination clinical trials may have contributed to the higher reporting rate of anemia in these studies (see Laboratory Abnormalities, Hematologic).

In vitro drug metabolism studies suggest that rosiglitazone does not inhibit any of the major P450 enzymes at clinically relevant concentrations. In vitro data demonstrate that rosiglitazone is predominantly metabolized by CYP2C8, and to a lesser extent, 2C9.

Rosiglitazone maleate (4 mg twice daily) was shown to have no clinically relevant effect on the pharmacokinetics of nifedipine and oral contraceptives (ethinylestradiol and norethindrone), which are predominantly metabolized by CYP3A4.
Glyburide: Rosiglitazone maleate (2 mg twice daily) taken concomitantly with glyburide (3.75 to 10 mg/day) for 7 days did not alter the mean steady-state 24-hour plasma glucose concentrations in diabetic patients stabilized on glyburide therapy.
Metformin: Concurrent administration of rosiglitazone maleate (2 mg twice daily) and metformin (500 mg twice daily) in healthy volunteers for 4 days had no effect on the steady-state pharmacokinetics of either metformin or rosiglitazone.
Acarbose: Coadministration of acarbose (100 mg three times daily) for 7 days in healthy volunteers had no clinically relevant effect on the pharmacokinetics of a single oral dose of rosiglitazone maleate.
Digoxin: Repeat oral dosing of rosiglitazone maleate (8 mg once daily) for 14 days did not alter the steady-state pharmacokinetics of digoxin (0.375 mg once daily) in healthy volunteers.
Warfarin: Repeat dosing with rosiglitazone maleate had no clinically relevant effect on the steady-state pharmacokinetics of warfarin enantiomers.
Ethanol: A single administration of a moderate amount of alcohol did not increase the risk of acute hypoglycemia in type 2 diabetes mellitus patients treated with rosiglitazone maleate.
Ranitidine: Pretreatment with ranitidine (150 mg twice daily for 4 days) did not alter the pharmacokinetics of either single oral or intravenous doses of rosiglitazone in healthy volunteers. These results suggest that the absorption of oral rosiglitazone is not altered in conditions accompanied by increases in gastrointestinal pH.

Limited data are available with regard to overdosage in humans. In clinical studies in volunteers, rosiglitazone maleate has been administered at single oral doses of up to 20 mg and was well-tolerated. In the event of an overdose, appropriate supportive treatment should be initiated as dictated by the patient’s clinical status.

The management of antidiabetic therapy should be individualized.
Monotherapy
The usual starting dose of rosiglitazone maleate is 4 mg administered either as a single dose once daily or in divided doses twice daily. For patients who respond inadequately following 12 weeks of treatment as determined by reduction in FPG, the dose may be increased to 8 mg administered as a single dose once daily or in divided doses twice daily.

Reductions in glycemic parameters by dose and regimen are described in CLINICAL STUDIES. In clinical trials, the 4 mg twice daily regimen resulted in the greatest reduction in FPG and HbA1c.
Combination Therapy with Metformin
The usual starting dose of rosiglitazone maleate in combination with metformin is 4 mg administered as either a single dose once daily or in divided doses twice daily. The dose of rosiglitazone maleate may be increased to 8 mg/day following 12 weeks of therapy if there is insufficient reduction in FPG. Rosiglitazone maleate may be administered as a single daily dose in the morning, or divided and administered in the morning and evening.
Rosiglitazone maleate may be taken with or without food.
No dosage adjustments are required for the elderly.
No dosage adjustment is necessary when rosiglitazone maleate is used as monotherapy in patients with renal impairment. Since metformin is contraindicated in such patients, concomitant administration of metformin and rosiglitazone maleate is also contraindicated in patients with renal impairment.
Therapy with rosiglitazone maleate should not be initiated if the patient exhibits clinical evidence of active liver disease or increased serum transaminase levels (ALT >2.5 times the upper limit of normal at start of therapy. Liver enzyme monitoring is recommended in all patients prior to initiation of therapy with rosiglitazone maleate and periodically thereafter.
There are no data on the use of rosiglitazone maleate in patients under 18 years of age; therefore, use of rosiglitazone maleate in pediatric patients is not recommended.

Management of type 2 diabetes should include diet control. Caloric restriction, weight loss, and exercise are essential for the proper treatment of the diabetic patient because they help improve insulin sensitivity. This is important not only in the primary treatment of type 2 diabetes, but in maintaining the efficacy of drug therapy.

It is important to adhere to dietary instructions and to regularly have blood glucose and glycosylated hemoglobin tested. Patients should be informed that blood will be drawn to check their liver function prior to the start of therapy and every two months for the first twelve months, and periodically thereafter. Patients with unexplained symptoms of nausea, vomiting, abdominal pain, fatigue, anorexia, or dark urine should immediately report these symptoms to their physician.
Rosiglitazone maleate can be taken with or without meals.
Use of rosiglitazone maleate may cause resumption of ovulation in premenopausal, anovulatory women with insulin resistance. Therefore, contraceptive measures may need to be considered.