二甲雙胍
Metformin
Metformin hydrochloride; Dimethylbiguanide HCl
別名: Glucophage XR · Glumetza · Fortamet · Riomet · Dimethylbiguanide HCl · Metforimini hydrochloridium
由 VetSheet 獸醫團隊審訂更新於 2026年4月5日本內容以實證獸醫文獻為本
劑量為合格獸醫專業人員的臨床參考。請務必對照最新仿單及個別病患確認。
各物種劑量
🌎 NA — North America🌍 EU — Europe
貓
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Non-insulin dependent diabetes mellitus (NIDDM) | 50 mg (total dose) per cat PO twice daily | PO | q12h | — | 🌎 NA |
| Early NIDDM | 2 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
| General Use Warning | Not recommended | PO | — | — | 🌎 NA |
- Non-insulin dependent diabetes mellitus (NIDDM): May be efficacious only in cats with detectable concentrations of insulin at time of treatment.
- General Use Warning: Author states 'metformin has been shown toxic to cats and should not be used. It is also ineffective.'
鳥
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| General | 100-500 mg/L of drinking water | PO | Continuous | — | 🌎 NA |
劑量為合格獸醫專業人員的臨床參考。請務必對照最新仿單及個別病患確認。
概覽
二甲雙胍 (Metformin) 是一種雙胍類口服降血糖藥物，在人類醫學中廣泛用於治療第二型糖尿病。在獸醫學中，其使用極具爭議，且通常被認為療效有限。
- 貓：曾被研究作為非胰島素依賴型糖尿病 (NIDDM) 的輔助治療。然而，臨床成功率極低，且由於胃腸道毒性，動物通常耐受性不佳。部分獸醫內分泌學家強烈建議不要在貓身上使用。
- 馬：曾被研究用於控制馬代謝症候群 (EMS) 和胰島素失調。不幸的是，二甲雙胍在馬體內的藥代動力學特徵極不理想，口服生物利用度極低（約 4-7%）且消除半衰期非常快，使其全身性療效受到質疑。
臨床要點：與磺醯脲類（如格列吡嗪）或胰島素不同，二甲雙胍不會刺激胰臟釋放胰島素，因此單獨使用時極少引起低血糖。
作用機轉
Metformin acts primarily as an insulin sensitizer and inhibitor of hepatic glucose output. Its actions are multifaceted:
- AMPK Activation: Metformin activates AMP-activated protein kinase (AMPK) in hepatocytes → decreases hepatic gluconeogenesis (glucose production).
- Peripheral Sensitization: Increases insulin's ability to transport glucose across cell membranes in skeletal muscle → increases peripheral glucose uptake.
- Intestinal Absorption: May decrease the intestinal absorption of dietary glucose.
- Advanced Glycosylation: Inhibits the formation of advanced glycosylation end-products.
Because it does not stimulate insulin production or release from pancreatic beta cells, it does not directly induce hypoglycemia.
安全性與警告
禁忌症
- Hypersensitivity to metformin
- Renal dysfunction
- Metabolic acidosis
- Concurrent use of parenteral iodinated contrast agents (temporary contraindication)
不良反應
- Lethargy
- Inappetence
- Vomiting
- Diarrhea
- Weight loss
- Lactic acidosis (rare but severe)
注意事項
Important Precautions:
- Renal Impairment: Metformin is primarily excreted unchanged by the kidneys. Accumulation can lead to severe lactic acidosis in patients with renal dysfunction.
- Gastrointestinal Toxicity: Has a narrow margin of safety regarding GI upset in small animals.
- Lactation: Excreted in maternal milk in levels equivalent to plasma. Use with caution in lactating queens.
- Dosing Challenges: Human dosage forms (e.g., 500 mg tablets) may be difficult to accurately dose in cats, increasing the risk of toxicity.
藥物交互作用
May increase risk for hypoglycemia
Can cause a 60% increase in peak metformin plasma levels and a 40% increase in AUC
May reduce hypoglycemic efficacy
May reduce hypoglycemic efficacy
Can increase the AUC and plasma levels of metformin by 22%; metformin can decrease the peak plasma concentrations and AUC of furosemide
May cause acute renal failure and lactic acidosis if used within 48 hours of a metformin dose
May reduce hypoglycemic efficacy
May reduce hypoglycemic efficacy
監測
- Fasting blood glucose
- Appetite and attitude
- Body condition
- PU/PD resolution
- Serum fructosamine and/or glycosylated hemoglobin levels
- Renal function (baseline and annually)
- Adverse effects (especially GI signs)
藥物動力學
半衰期
吸收
Cats: Variably absorbed after oral administration (35-67%). Horses: Very low oral bioavailability (4% fed, 7% fasted).
分佈
Cats: Steady-state volume of distribution is 0.55 L/kg.
代謝
Not extensively metabolized.
排除
Primarily eliminated via the kidneys. Cats: Total clearance is 0.15 L/hr/kg.
過量
Overdose & Toxicity Profile:
- Small Animals: Hypoglycemia is not commonly seen in overdoses of metformin alone. However, the drug has a narrow margin of safety regarding gastrointestinal upset.
- Clinical Signs: Vomiting and diarrhea are the most common findings in dogs and cats following accidental ingestion.
- Human Data: Massive overdoses (e.g., 100 grams) caused hypoglycemia only 10% of the time, but lactic acidosis occurred. Lactic acidosis has been seen in human overdoses of 7 to 20 grams. It is unknown at what exact dose acidosis may occur in domestic animals.
Management: Treatment is largely supportive and symptomatic, focusing on managing GI distress and monitoring acid-base status and renal function.
可用產品
劑型
- Extended-Release Oral Tablets
- Oral Solution
人用標示
- Metformin HCl Oral Tablets: 500 mg, 850 mg & 1000 mg (Glucophage, generic)
- Metformin HCl Extended-Release Oral Tablets: 500 mg, 750 mg & 1000 mg (Glucophage XR, Glumetza, Fortamet, generic)
- Metformin HCl Oral Solution: 500 mg/5 mL (Riomet)
各地核准狀態
暫無法規資料: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
儲存與穩定性
Store protected from light at a controlled room temperature of 20-25°C (68-77°F), with excursions permitted to 15-30°C (59-86°F).
飼主須知
寵物主人指引：
- 試驗性用途：請了解在貓咪身上使用二甲雙胍具有高度的「試驗性質」且屬於仿單標示外使用。其在獸醫學中的有效性仍有爭議。
- 副作用：密切觀察是否有腸胃不適的跡象，包括嘔吐、腹瀉、食慾不振或極度嗜睡。
- 回報：若發現寵物有任何不良反應或行為改變，請立即向您的獸醫師回報。
- 給藥方式：除非獸醫師特別指示，否則請勿壓碎或剝半緩釋錠。請確保寵物隨時有乾淨的飲水。
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