甲基睪酮
Methyltestosterone
17beta-Hydroxy-17alpha-methylandrost-4-ene-3-one
別名: Android · Methitest · Testred · Virilon · Orandrone · NSC-9701 · 17-alpha-methyltestosterone
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
劑量為持牌獸醫專業人員的臨床參考。請務必對照最新藥品說明書及個別病患確認。
各物種劑量
🌎 NA — North America🌍 EU — Europe
狗
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Alopecia X (when melatonin fails) | 1 mg/kg to a maximum dose of 30 mg (total dose) | PO | once daily | Stop after maximal hair re-growth is noted | 🌎 NA |
| Testosterone-responsive dermatosis | 1 mg/kg to a maximum dose of 30 mg | PO | every other day | Once dog responds, then every 4-7 days | 🌎 NA |
| Suppress estrus in Greyhounds | 5 mg (total dose) | PO | once weekly or divided, two times a week | — | 🌎 NA |
| Estrus suppression | 25-50 mg (total dose) | PO | twice weekly | — | 🌎 NA |
| Anti-estrogenic activity, anabolic effects, negative feedback on gonadotropin release | 0.5 mg/kg | PO | once daily | — | 🌎 NA |
- Alopecia X (when melatonin fails): Get baseline liver profile and then again one and two months after starting treatment. Can cause hepatotoxicity, aggressive behavior and/or seborrhea.
- Anti-estrogenic activity, anabolic effects, negative feedback on gonadotropin release: Dose may need to be adjusted, but should not exceed 1 mg/kg.
貓
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Anti-estrogenic activity, anabolic effects, negative feedback on gonadotropin release | 0.5 mg/kg | PO | once daily | — | 🌎 NA |
- Anti-estrogenic activity, anabolic effects, negative feedback on gonadotropin release: Dose may need to be adjusted, but should not exceed 1 mg/kg. Use is highly controversial due to hepatotoxicity.
劑量為持牌獸醫專業人員的臨床參考。請務必對照最新藥品說明書及個別病患確認。
概覽
甲基睪酮 (Methyltestosterone) 是一種合成的雄性激素與同化類固醇。它是睪酮的 17-α-烷基化衍生物，這項結構改變顯著降低了肝臟的首過代謝效應，使其能透過口服有效吸收。
在獸醫學中，主要用於：
- 荷爾蒙反應性皮膚病：特別是當褪黑激素治療無效時，用於犬隻的 X型脫毛症 (Alopecia X)（毛髮生長週期停滯）。
- 生殖管理：抑制母犬發情或治療假孕。
- 荷爾蒙依賴性腫瘤：作為某些雌激素依賴性乳腺腫瘤的輔助治療。
臨床要點：在獸醫臨床上（尤其是貓）使用此藥物極具爭議，且通常不建議使用，因為有引發嚴重肝毒性的高風險。貓似乎對 17-α-烷基化雄性激素引起的肝損傷特別敏感。
作用機制
Methyltestosterone acts as an exogenous androgen, binding to intracellular androgen receptors (AR) in target tissues.
- Mechanism: Free methyltestosterone enters cells → binds to cytosolic AR → the receptor-ligand complex translocates to the nucleus → binds to specific DNA sequences (androgen response elements) → modulates gene transcription.
- Anabolic Effects: Stimulates erythropoiesis (increases red blood cell production), enhances nitrogen balance, promotes protein anabolism (requires adequate caloric and protein intake), and increases retention of potassium, sodium, and phosphorus.
- Pharmacokinetic Advantage: The addition of a methyl group at the C-17 alpha position sterically hinders hepatic degradation, providing higher oral bioavailability compared to native testosterone.
安全性與警告
禁忌症
- Hepatic dysfunction or pre-existing liver disease
- Pregnancy (Category X - causes fetal masculinization)
- Prostate cancer or severe prostatic hypertrophy
不良反應
- Hepatotoxicity (elevated liver enzymes, icterus, periportal hepatocyte enlargement)
- Virilization of females (clitoral hypertrophy, vaginitis)
- Vaginal discharge
- Prostatic hyperplasia in males
- Increased aggression or behavioral changes
- Seborrhea
- Premature epiphyseal closure in young animals
注意事項
Important Precautions
- Hepatotoxicity: Chronic use is strongly associated with liver damage. Baseline and serial liver enzyme monitoring is mandatory.
- Cardiac Disease: Use with extreme caution in patients with heart failure due to the potential for sodium and water retention.
- Growing Animals: Prolonged use in young, growing animals can cause premature epiphyseal closure, stunting growth.
- Laboratory Interference: Can decrease thyroxine-binding globulin, leading to decreased total T4 levels (free T4 remains unaffected).
藥物相互作用
Methyltestosterone may increase serum cyclosporine levels, potentially leading to toxicity.
Methyltestosterone may decrease serum glucose levels, reducing insulin requirements.
May decrease serum glucose levels, increasing the risk of hypoglycemia.
Methyltestosterone may increase anticoagulant effects, increasing bleeding risk.
監測
- Baseline and serial hepatic function panels (ALT, AST, ALP, Bilirubin)
- Clinical signs of hepatotoxicity (icterus, anorexia, weight loss, vomiting)
- Behavioral changes (aggression)
- Prostatic evaluation in intact males
藥物動力學
吸收
Absorbed from the GI tract and oral mucosa. Undergoes significantly less first-pass hepatic metabolism than orally administered native testosterone due to 17-alpha alkylation.
分佈
Highly protein-bound in plasma, primarily to sex hormone-binding globulin (SHBG) and albumin.
代謝
Metabolized in the liver. In dogs, principle metabolites found in urine are glucuronidated forms (both conjugated and free) of methyltestosterone. Unlike humans, sulfated forms are not a major metabolic component.
排除
Excreted primarily in the urine as conjugated metabolites.
過量
Information on acute toxicity in veterinary species is limited.
- Acute signs: Nausea, vomiting, and edema are the most likely effects of a single massive overdose.
- Management: Consider gastrointestinal decontamination if ingestion is recent. Monitor liver function closely with large overdoses and provide supportive care.
可用產品
劑型
- Oral tablets
- Buccal tablets
- Oral capsules
人用標示
- Methyltestosterone Tablets: 10 mg & 25 mg (Methitest, generic)
- Methyltestosterone Buccal Tablets: 10 mg (generic)
- Methyltestosterone Capsules: 10 mg (Testred, Android, Virilon)
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 tablets or capsules below 40°C, preferably between 15°-30°C (59°-86°F) in well-closed containers, unless otherwise specified by the manufacturer.
飼主須知
寵物主人重要須知
- 用途：這是一種荷爾蒙藥物，用於治療特定的脫毛問題（如 X型脫毛症）或管理某些生殖問題。
- 肝臟風險：最嚴重的副作用是肝臟損傷。在開始使用此藥物前以及治療期間，必須定期進行血液檢查，以確保寵物的肝臟功能正常。
- 行為改變：請密切觀察寵物是否出現攻擊性增加或與平時不同的行為改變。
- 生理變化：母犬可能會出現雄性化的生理特徵或陰道分泌物。公犬可能會出現前列腺問題。
- 何時應聯繫獸醫師：如果您的寵物出現食慾不振、嘔吐、體重快速下降，或您發現其眼睛、牙齦或皮膚變黃（黃疸），請立即停藥並聯繫您的獸醫師。
- 人類安全警告：孕婦應避免接觸此藥物，因為它可能導致嚴重的胎兒先天性缺陷。
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