Glipizide
**Glipizide** is a second-generation oral sulfonylurea antidiabetic agent primarily used in human medicine for Type II diabetes, but it has specific applications in veterinary medicine, particularly for feline patients. * **Feline Application**: It may be beneficial in treating cats with uncomplicated diabetes mellitus who still possess a population of functioning pancreatic beta cells. Approximately **20% to 30%** of newly diagnosed diabetic cats may respond to glipizide therapy. * **Clinical Utility**: It is typically reserved for situations where owners absolutely refuse insulin injections (often due to needle phobia) or when a cat is well-controlled on minute doses of insulin and the owner wishes to transition to an oral medication. * **Canine Limitation**: Glipizide is generally **ineffective in dogs**. By the time dogs present with clinical hyperglycemia, they are typically absolutely or relatively insulinopenic (similar to human Type I diabetes) and lack the functional beta cells required for glipizide to work. * **Clinical Pearl**: A glipizide trial requires patience; it may take **4 to 8 weeks** before full therapeutic effects are observed. Furthermore, prolonged use in cats may contribute to increased islet amyloid deposition, potentially accelerating the destruction of remaining beta cells.
Mecanismo: Glipizide lowers blood glucose concentrations by stimulating the release of endogenous insulin from the pancreas and enhancing peripheral insulin sensitivity. * **Pancreatic Mechanism**: Glipizide binds to the **sulfonylurea receptor 1 (SUR1)** on the membrane of pancreatic **β-cells** → This binding closes **ATP-sensitive potassium (K+) channels** → Decreased potassium efflux leads to **cellular depolarization** → Depolarization opens **voltage-dependent calcium (Ca2+) channels** → Calcium influx triggers the exocytosis of **insulin**-containing secretory granules. * **Extrapancreatic Effects**: Ongoing use enhances peripheral tissue sensitivity to circulating insulin and reduces the production of hepatic basal glucose, though the exact mechanisms for these secondary effects remain partially unexplained.
Dosificación por especie
- Diabetes mellitus (non-ketotic, relatively healthy) · 2.5 mg per cat (initially), may increase to 5 mg per cat · PO · q12h · Ongoing if stable · Give in conjunction with a meal. Perform spot BG checks every 3-4h for initial 12-18h. Increase dose to 5 mg BID after 2 weeks if hyperglycemia persists and no adverse reactions occur.
- Diabetes mellitus · 2.5-5 mg per cat · PO · q12h · 2-3 months trial · Combine with dietary fiber therapy. Evaluate every 1-2 weeks. If fasting BG remains >200 mg/dL after 2-3 months, discontinue and institute insulin.
- Diabetes mellitus (mild weight loss, non-ketoacidotic, no peripheral neuropathy) · 2.5 mg (total dose) · PO · q12h
- Diabetes mellitus · 5 mg per cat, may increase to 7.5 mg (maximum) · PO · q12h · 4-8 weeks trial · Decrease dose if hypoglycemia occurs. Response may be delayed; evaluate over 4-8 weeks before determining efficacy.
- Non-ketotic diabetes mellitus · 2.5-5 mg per cat · PO · q12h · Start at the lower end of the dose range, increasing the dose as required if no adverse effects are reported after 2 weeks.
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Severe burns, trauma, or infection
- Diabetic coma or other hypoglycemic conditions
- Major surgery
- Ketosis, ketoacidosis, or other significant acidotic conditions
- Known hypersensitivity to sulfonylureas
- Diabetic ketosis / ketoacidosis
- Hepatic impairment
- Renal impairment
- Absolute insulin deficiency (Type I diabetes)
- Insulin resistance
Efectos adversos
- Gastrointestinal upset (anorexia, vomiting in ~15% of cats)
- Hypoglycemia (severe cases are rare)
- Hepatotoxicity (cholestatic jaundice and elevated liver enzymes in ~8% of cats)
- Increased pancreatic amyloid deposit formation
- Allergic skin reactions (reported in humans)
- Bone marrow suppression (reported in humans)
- Vomiting
- Hypoglycemia
- Jaundice (hepatotoxicity)
- Skin rashes
- Fever
Interacciones farmacológicas
- Alcohol · May cause a disulfiram-like reaction (anorexia, nausea, vomiting)
- Azole Antifungals (ketoconazole, itraconazole, fluconazole) · May increase plasma levels of glipizide
- Beta-blockers · May potentiate hypoglycemic effect and mask signs of hypoglycemia
- Chloramphenicol · May displace glipizide from plasma proteins, increasing effect · moderate
- Cimetidine · May potentiate hypoglycemic effect
- Corticosteroids · May antagonize insulin effects and reduce glipizide efficacy
- Thiazide Diuretics · May reduce hypoglycemic efficacy
- Isoniazid · May reduce hypoglycemic efficacy
- MAO Inhibitors · May potentiate hypoglycemic effect
- Niacin · May reduce hypoglycemic efficacy
- Phenothiazines · May reduce hypoglycemic efficacy
- Phenytoin · May reduce hypoglycemic efficacy
- Probenecid · May potentiate hypoglycemic effect
- Sulfonamides · May displace glipizide from plasma proteins, increasing effect
Monitorización
- Physical examination and body weight (weekly during first month)
- Urine glucose and ketones
- Serial blood glucose measurements or spot checks
- Liver enzymes (ALT, AST, ALP) and bilirubin (every 1-2 weeks initially)
- Complete Blood Count (CBC)
- Clinical signs of hypoglycemia or gastrointestinal distress
- Blood glucose curves
- Fructosamine levels
- Liver enzymes (ALT, AST, ALP, Bilirubin)
- Renal function (BUN, Creatinine)
- Clinical signs of diabetes (water intake, urination, weight)
Sobredosis
**Toxicity Profile**: Oral LD50 is greater than 4 g/kg in all tested animal species. The primary and most dangerous consequence of an overdose is **profound hypoglycemia**. **Management**: * **Decontamination**: Employ gut-emptying protocols (emesis, activated charcoal) if the ingestion is recent and the patient is asymptomatic. * **Treatment**: Monitor blood glucose closely. Administer parenteral glucose (e.g., IV dextrose bolus followed by a CRI) as needed. * **Monitoring**: Because of its relatively short half-life, prolonged hypoglycemia is less likely compared to older sulfonylureas (like chlorpropamide), but blood glucose monitoring and supportive care may still be required for several days. Massive overdoses may require monitoring of blood gases and serum electrolytes.
La referencia de fármacos de VetSheet está destinada a veterinarios colegiados como apoyo a la decisión clínica, no sustituye el juicio profesional ni la ficha técnica vigente del fabricante.