グリピジド
**グリピジド**は、主にヒトの2型糖尿病に使用される第2世代の経口スルホニル尿素系抗糖尿病薬ですが、獣医学、特に猫の患者において特定の用途があります。 * **猫への応用**: 機能している膵臓β細胞の集団がまだ残っている合併症のない糖尿病の猫の治療に有益な場合があります。新たに診断された糖尿病の猫の約**20%〜30%**がグリピジド療法に反応する可能性があります。 * **臨床的有用性**: 通常、飼い主が（多くの場合、注射恐怖症のために）インスリン注射を絶対に拒否する場合、または猫がごく微量のインスリンで良好にコントロールされており、飼い主が経口薬への移行を希望する場合に限定して使用されます。 * **犬における制限**: グリピジドは一般的に**犬には無効**です。犬が臨床的な高血糖を呈する頃には、通常、絶対的または相対的なインスリン欠乏状態（ヒトの1型糖尿病に類似）にあり、グリピジドが機能するために必要な機能的β細胞が不足しています。 * **臨床のポイント**: グリピジドの試験的投与には忍耐が必要です。完全な治療効果が観察されるまでに**4〜8週間**かかる場合があります。さらに、猫での長期使用は膵島アミロイド沈着の増加を促進し、残存するβ細胞の破壊を加速させる可能性があります。
作用機序: 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.
動物種別の用量
- 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.
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- 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
有害事象
- 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
薬物相互作用
- 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
モニタリング
- 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)
過量投与
**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.
VetSheet の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。