維生素C / 抗壞血酸
Ascorbic Acid
L-ascorbic acid
別名: Vitamin C · Ascor L 500 · L-ascorbic acid · Antiscorbutic vitamin · Ascorbate
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
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概覽
抗壞血酸（維生素C）是一種水溶性維生素，對膠原蛋白合成、組織修復和抗氧化防禦至關重要。
雖然大多數家畜（如狗、貓、馬）能在肝臟中自行合成足夠的維生素C，但某些物種（最著名的是天竺鼠、非人類靈長類動物以及某些蝙蝠和鳥類）缺乏L-古洛糖酸內酯氧化酶，因此需要透過飲食補充。
在獸醫學中，抗壞血酸主要用於：
- 治療和預防易感物種（如天竺鼠）的壞血病。
- 在重症監護或溶血事件中作為輔助抗氧化療法。
- 作為尿液酸化劑。
- 協助處理特定毒性反應（例如馬的紅楓葉中毒或普拿疼中毒），因其具有還原變性血紅素的特性。
作用機制
Ascorbic acid acts as a vital coenzyme and a powerful water-soluble antioxidant.
- Collagen Synthesis: It is an essential cofactor for the enzymes prolyl hydroxylase and lysyl hydroxylase → facilitates the hydroxylation of proline and lysine residues → allows for the formation of a stable collagen triple helix.
- Antioxidant Activity: Scavenges reactive oxygen species (ROS) → protects lipid membranes, DNA, and proteins from oxidative damage.
- Methemoglobin Reduction: Assists in the reduction of methemoglobin back to functional hemoglobin, which is beneficial in certain oxidative toxicities.
- Iron Absorption: Enhances the gastrointestinal absorption of non-heme iron and regulates iron transport.
安全性與警告
禁忌症
- Patients with a history of urate or calcium oxalate urolithiasis
- Use with caution in patients with iron storage diseases (e.g., hemochromatosis)
- Patients with a history of calcium oxalate or urate urolithiasis (due to urine acidification)
不良反應
- Gastrointestinal upset (diarrhea) with high oral doses
- Pain or tissue irritation at the injection site (IM or SC)
- Increased risk of calcium oxalate urolithiasis with chronic high-dose administration
- Gastrointestinal upset (diarrhea) at high oral doses
- Pain at injection site (IM/SC)
- Potential to acidify urine, which may increase the risk of oxalate or urate urolithiasis
注意事項
Use with extreme caution in animals prone to calcium oxalate urolithiasis, as ascorbic acid is partially metabolized to oxalate and excreted in the urine. Intravenous administration should be performed slowly to avoid adverse cardiovascular events. Injectable solutions should be protected from light.
藥物相互作用
Concurrent use may exacerbate tissue iron toxicity, particularly in the heart.
May have additive acidifying effects, potentially increasing the risk of crystalluria.
監測
- Clinical signs of disease resolution (e.g., improvement of scurvy symptoms in guinea pigs)
- Urine pH (if utilized specifically as a urinary acidifier)
- Resolution of clinical signs of scurvy (in susceptible species)
- Urine pH (if using high doses)
藥物動力學
半衰期
吸收
Readily absorbed from the gastrointestinal tract (primarily the jejunum) via active transport mechanisms.
分佈
Widely distributed to all body tissues; particularly high concentrations are found in glandular tissue, leukocytes, the liver, and the lens of the eye.
代謝
Reversibly oxidized to dehydroascorbic acid; partially metabolized in the liver to inactive compounds, including oxalic acid.
排除
Excreted primarily in the urine. A renal threshold exists; once tissue saturation is reached, excess ascorbic acid is excreted unchanged in the urine.
過量
Ascorbic acid is generally very safe due to its water-soluble nature; excess amounts are rapidly excreted in the urine. Massive acute overdoses may cause gastrointestinal disturbances (such as diarrhea) or mild acidosis. Chronic overdosage significantly increases the risk of calcium oxalate urolithiasis.
可用產品
劑型
- Injection: 500 mg/mL in 50 mL vials (0.025% EDTA, preservative-free)
- Injectable: 100 mg/ml
- Oral: various strength tablets, capsules, powders and liquids
獸醫用
- Ascor L 500® (McGuff): 500 mg/mL injection in 50 mL vials
- Various injectable solutions (100 mg/ml) (POM)
- Various oral supplements (General Sale)
人用標示
- Various over-the-counter oral tablets, capsules, chewables, and liquids
- Generic injectable formulations
- Various tablets, capsules, chewables, powders, and liquids
各地核准狀態
Injectable forms are typically POM (Prescription Only Medicine), while oral forms are General Sale.
Injectable forms are POM-V; oral forms are General Sale List (GSL).
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儲存與穩定性
Store intact vials at controlled room temperature and protect from light. Preservative-free solutions should be used promptly after opening, and any unused portion should be discarded.
飼主須知
重點提示：大多數狗和貓能自行製造維生素C，除非獸醫特別指示，否則不需要額外補充。
- 天竺鼠無法自行製造維生素C，必須每天透過強化飲食或特定的維生素C滴劑補充。
- 維生素C接觸光線和空氣後容易降解，請將補充劑存放在陰涼避光處。
- 若您的寵物被處方高劑量維生素C，請觀察其排便狀況；如出現腹瀉請聯繫獸醫。
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