Brands, Medical Use, Clinical Data
Drug Category
Dosage Forms
- Immediate-release oral tablets
- Extended-release oral tablets
Brands / Synonyms
Aldiab; Apamid; Digrin; Dipazide; Glibenese; Glibetin; Glican; Glide; Glidiab; Glipid; Glipizida [Inn-Spanish]; Glipizide; Glipizide and Metformin; Glipizide Extended-Release Tablets; Glipizidum [Inn-Latin]; Gluco-Rite; Glucolip; Glucotrol; Glucotrol XL; Glucozide; Glupitel; Glupizide; Glyde; Glydiazinamide; Melizide; Metaglip; Mindiab; Minidab; Minidiab; Minodiab; Napizide; Ozidia; Sucrazide
Indications
For use as an adjunct to diet for the control of hyperglycemia and its associated symptomatology in patients with non-insulin-dependent diabetes mellitus (NIDDM; type II), formerly known as maturity-onset diabetes, after an adequate trial of dietary therapy has proved unsatisfactory.
Pharmacology
Glipizide, a second-generation sulfonylurea, is used with diet to lower blood glucose in patients with diabetes mellitus type II. The primary mode of action of glipizide in experimental animals appears to be the stimulation of insulin secretion from the beta cells of pancreatic islet tissue and is thus dependent on functioning beta cells in the pancreatic islets. In humans glipizide appears to lower the blood glucose acutely by stimulating the release of insulin from the pancreas, an effect dependent upon functioning beta cells in the pancreatic islets. In man, stimulation of insulin secretion by glipizide in response to a meal is undoubtedly of major importance. Fasting insulin levels are not elevated even on long-term glipizide administration, but the postprandial insulin response continues to be enhanced after at least 6 months of treatment. Some patients fail to respond initially, or gradually lose their responsiveness to sulfonylurea drugs, including glipizide.
Mechanism of Action
Sulfonylureas likely bind to ATP-sensitive potassium-channel receptors on the pancreatic cell surface, reducing potassium conductance and causing depolarization of the membrane. Depolarization stimulates calcium ion influx through voltage-sensitive calcium channels, raising intracellular concentrations of calcium ions, which induces the secretion, or exocytosis, of insulin.
Absorption
Gastrointestinal absorption is uniform, rapid, and essentially complete.
Toxicity
The acute oral toxicity was extremely low in all species tested (LD50 greater than 4 g/kg). Overdosage of sulfonylureas including glipizide can produce hypoglycemia.
Biotrnasformation / Drug Metabolism
Hepatic. The major metabolites of glipizide are products of aromatic hydroxylation and have no hypoglycemic activity. A minor metabolite which accounts for less than 2% of a dose, an acetylaminoethyl benzine derivatives, is reported to have 1/10 to 1/3 as much hypoglycemic activity as the parent compound.
Contraindications
Immediate and Extended Release Tablets
Glipizide is contraindicated in patients with:
1. Known hypersensitivity to the drug.
2. Diabetic ketoacidosis, with or without coma. This condition should be treated with insulin.
Drug Interactions
Immediate and Extended Release Tablets
The hypoglycemic action of sulfonylureas may be potentiated by certain drugs including nonsteroidal
anti-inflammatory agents, some azoles and other drugs that are highly protein bound, salicylates, sulfonamides,
chloramphenicol, probenecid, coumarins, monoamine oxidase inhibitors, and beta adrenergic blocking agents. When such
drugs are administered to a patient receiving glipizide, the patient should be observed closely for hypoglycemia.
When such drugs are withdrawn from a patient receiving glipizide, the patient should be observed closely for loss of
control. In vitro binding studies with human serum proteins indicate that glipizide binds differently than
tolbutamide and does not interact with salicylate or dicumarol. However, caution must be exercised in extrapolating
these findings to the clinical situation and in the use of glipizide with these drugs.
Certain drugs tend to produce hyperglycemia and may lead to loss of control. These drugs include the thiazides and
other diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin,
nicotinic acid, sympathomimetics, calcium channel blocking drugs, and isoniazid. When such drugs are administered to
a patient receiving glipizide, the patient should be closely observed for loss of control. When such drugs are
withdrawn from a patient receiving glipizide, the patient should be observed closely for hypoglycemia.
A potential interaction between oral miconazole and oral hypoglycemic agents leading to severe hypoglycemia has
been reported. Whether this interaction also occurs with the intravenous, topical, or vaginal preparations of
miconazole is not known. The effect of concomitant administration of fluconazole and glipizide has been demonstrated
in a placebo-controlled crossover study in normal volunteers. All subjects received glipizide alone and following
treatment with 100 mg of fluconazole as a single daily oral dose for seven days. The mean percentage increase in the
glipizide AUC after fluconazole administration was 56.9% (range: 35 to 81).
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