Avandia

Action

Inhibits alpha-glucosidases, enzymes that convert oligosaccharides and disaccharides to glucose. This inhibition lowers blood glucose level, especially in postprandial hyperglycemia.

Availability

Tablets: 2 mg, 4 mg, 8 mg

Indications and dosages

➣ Adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus who are either already taking rosiglitazone or not already taking rosiglitazone and are unable to achieve adequate glycemic control on other antidiabetics and, in consultation with their healthcare provider, have decided not to take pioglitazone for medical reasons

Adults: 4 mg P.O. once daily or 2 mg b.i.d. After 8 to 12 weeks, may increase to 8 mg daily or 4 mg b.i.d. if needed.

Off-label uses

• Polycystic ovary syndrome

Contraindications

• Established New York Heart Association (NYHA) Class III or IV heart failure

Precautions

Use cautiously in:

• diabetic ketoacidosis, type 1 (insulin-dependent) diabetes mellitus (use not recommended)

• edema, NYHA Class I and II heart failure, elevated liver enzymes, jaundice

• concurrent use of insulin (not recommended)

• pregnant patients

• breastfeeding patients (use not recommended)

• children (safety and efficacy not established).

Administration

☞ Obtain liver enzyme results before starting drug. Be aware that therapy shouldn't be initiated in patient with elevated baseline liver enzyme levels (alanine aminotransferase [ALT] level greater than 2.5 times the upper limit of normal) or if patient exhibits clinical evidence of active liver disease.

• Give with or without food.

• Be aware that drug is active only in presence of endogenous insulin and thus is ineffective in diabetic ketoacidosis or type 1 diabetes mellitus.

Adverse reactions

CNS: fatigue, headache

CV: hypertension, heart failure, increased risk of myocardial infarction

EENT: macular edema, decreased visual acuity, nasopharyngitis

GI: diarrhea

GU: menstrual dysfunction

Hematologic: anemia

Metabolic: hyperglycemia, hypoglycemia

Musculoskeletal: back pain, arthralgia, increased risk of fracture

Respiratory: upper respiratory infection

Other: edema, injury, weight gain

Interactions

Drug-drug. CYP2C8 inducers (such as rifampin): decreased rosiglitazone area under the curve (AUC)

CYP2C8 inhibitors (such as gemfibrozil): increased rosiglitazone AUC

Drug-diagnostic tests. Free fatty acids, high-density lipoproteins, liver enzymes, low-density lipoproteins, total cholesterol: increased levels

Hematocrit, hemoglobin: decreased levels

Patient monitoring

• Monitor CBC, lipid panel, blood glucose, and glycosylated hemoglobin levels.

• Monitor patient's weight. Assess for fluid retention, which may lead to heart failure. Be aware that dosage increases should be accompanied by careful monitoring for adverse reactions related to fluid retention.

☞ Closely monitor liver function tests. Be aware that patients with mildly elevated liver enzymes (ALT level 2.5 times ULN) at baseline or during therapy should be evaluated to determine cause of the liver enzyme elevation and if liver enzyme elevation resolves or worsens. If at any time ALT level increases to more than 3 times ULN, recheck liver enzyme levels as soon as possible. If ALT level remains at 3 times ULN, discontinue drug. If jaundice occurs, discontinue drug.

Patient teaching

• Tell patient he may take with or without food.

• Advise patient to monitor blood glucose level regularly and report significant changes.

☞ Inform patient that drug may increase fluid retention, causing or exacerbating heart failure. Encourage him to weigh himself regularly and report sudden weight gain, swelling, or shortness of breath.

☞ Teach patient to recognize and immediately report signs and symptoms of heart attack or liver problems.

• Tell patient to promptly report vision changes.

• Tell patient he'll undergo regular blood testing during therapy.

• Advise female patient that drug may result in ovulation in some premenopausal anovulatory women. Inform patient she may be at increased risk for pregnancy while taking this drug; recommend adequate contraception.

• Caution female patient not to breastfeed during therapy.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the tests and herbs mentioned above.