GLYBURIDE

(glye'byoor-ide)

DiaBeta, Euglucon

, Glynase, Micronase
Classifications: hormone; antidiabetic agent; sulfonylurea;
Therapeutic: antidiabetic; sulfonylurea
Pregnancy Category: C

Availability

1.25 mg, 2.5 mg, 5 mg tablets; 1.5 mg, 3 mg, 4.5 mg, 6 mg micronized tablets

Action

One of the most potent of the second-generation sulfonylurea hypoglycemic agents. Potency is enhanced by as much as 200-fold over first-generation agents. Appears to lower blood sugar concentration in both diabetic and nondiabetic individuals by sensitizing functioning pancreatic beta cells to release insulin in the presence of elevated serum glucose levels.

Therapeutic Effect

Blood glucose-lowering effect persists during long-term glyburide treatment, but there is a gradual decline in meal-stimulated secretion of endogenous insulin toward pretreatment levels.

Uses

Adjunct to diet to lower blood glucose in patients with type 2 diabetes mellitus; after dietary control alone has failed.

Contraindications

Hypersensitivity to glyburide or sulfonylureas; diabetic ketoacidosis; as sole therapy for type 2 diabetes mellitus; moderate or severe renal impairment (Cl_cr <50 mL/min) or renal failure; pregnancy (category C); withhold 14 d before labor and delivery; lactation. Safe use in children is not established.

Cautious Use

Limit use in patients with cardiovascular disease; thyroid disease; mild renal impairment or hepatic disease; older adults, debilitated, or malnourished patients; adrenal or pituitary insufficiency.

Route & Dosage

Control of Hyperglycemia
Adult: PO 1.25–5 mg/d with breakfast, may increase by 2.5–5 mg q1–2wk; >15 mg/d should be given in divided doses with morning and evening meal (max: 20 mg/d); Micronized 1.5–3 mg/d (max: 12 mg/d)

Administration

Oral

Give once daily in the morning with breakfast or with first main meal.
Store in tightly closed, light-resistant container at 15°–30° C (59°–86° F).

Adverse Effects (≥1%)

Metabolic: Hypoglycemia. GI: Epigastric fullness, heartburn, nausea, vomiting. Skin: Pruritus, erythema, urticarial or cholestatic jaundice (rare) morbilliform eruptions. Special Senses: Blurred vision.

Interactions

Drug: Alcohol causes disulfiram-like reaction in some patients; oral anticoagulants, chloramphenicol, clofibrate, phenylbutazone, mao inhibitors, salicylates, probenecid, sulfonamides may potentiate hypoglycemic actions; thiazides may antagonize hypoglycemic effects; cimetidine may increase glyburide levels, causing hypoglycemia. Herbal: Ginseng, garlic may increase hypoglycemic effects.

Pharmacokinetics

Absorption: Readily absorbed from GI tract. Onset: 15–60 min. Peak: 1–2 h. Duration: Up to 24 h. Distribution: Distributed in highest concentrations in liver, kidneys, and intestines; crosses placenta. Metabolism: Extensively in liver. Elimination: Equally in urine and feces. Half-Life: 10 h.

Nursing Implications

Assessment & Drug Effects

Monitor blood glucose levels carefully during the dangerous early treatment period when dosage is being individualized. Older adults are especially vulnerable to glyburide-induced hypoglycemia (see Appendix F) because the antidiabetic agent is long-acting.
Note: The first signs of hypoglycemia may be hard to detect when the patient is also receiving a beta blocker or is an older adult.
Lab tests: Monitor at regular intervals: Blood and urine glucose, HbA_1c, urine ketones, and liver function tests.

Patient & Family Education

Eat or drink some form of sugar (e.g., corn syrup, orange juice with 2 or 3 tsp of table sugar) when symptoms of hypoglycemia occur. Report reaction to physician promptly.
Remember that loss of control of diabetes may result from stress such as fever, surgery, trauma, or infection. Check blood glucose and urine for ketones more frequently during stress periods; transfer from the sulfonylurea to insulin may be necessary.
Keep all follow-up medical appointments and adhere to dietary instructions, regular exercise program, and scheduled urine and blood testing.
Report blurred vision to physician.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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