多西環素
Doxycycline
Doxycycline calcium, Doxycycline hyclate, Doxycycline monohydrate
別名: Vibramycin · Doxirobe · Periostat · Doryx · Oracea · Monodox · Adoxa · Atridox · Doxybactin · Ronaxan · Doxycycline hydrochloride · Doxycycline monohydrate · Doxycyclinum · GS-3065 · Doxycycline hyclate
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
經審核的 v13 劑量證據
結構化劑量計算證據Borreliosis (ie, Borrelia burgdorferi [Lyme disease]) (extra-label)
- q12-24h
NA
必須同時考慮的臨床上下文 (2)
- ■ Do not give multivitamins, calcium supplements, antacids, or laxatives 2 hours before or after giving doxycycline as these products can reduce effectiveness of the medicine.
- Doxycycline hyclate tablets and capsules should be stored in tight, light-resistant containers below 30°C (86°F), preferably at controlled room temperature (15°C to 30°C [59°F-86°F]). After being reconstituted with water, the monohydrate oral suspension is stable for 14 days when stored at room temperature.
Susceptible bacterial infections (extra-label)
- q12-24h
NA
必須同時考慮的臨床上下文 (2)
- ■ Do not give multivitamins, calcium supplements, antacids, or laxatives 2 hours before or after giving doxycycline as these products can reduce effectiveness of the medicine.
- Doxycycline hyclate tablets and capsules should be stored in tight, light-resistant containers below 30°C (86°F), preferably at controlled room temperature (15°C to 30°C [59°F-86°F]). After being reconstituted with water, the monohydrate oral suspension is stable for 14 days when stored at room temperature.
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
多西環素是一種廣效、半合成的四環黴素類抗生素，衍生自土黴素（oxytetracycline）。由於其與舊型四環黴素相比具有良好的藥代動力學特性，在獸醫學中被廣泛使用。
主要臨床優勢：
- 高脂溶性： 組織穿透力極佳，包括中樞神經系統（CSF）、前列腺和眼睛。
- 腎臟安全性： 與其他四環黴素不同，多西環素主要以無活性的螯合物形式經糞便排泄。它不會在腎功能不全的患者體內蓄積，是氮血症患者的首選四環黴素。
- 心絲蟲輔助治療： 多西環素是現代犬心絲蟲治療方案的重要組成部分。它能消除心絲蟲生存和繁殖所必需的內共生細菌 Wolbachia，從而削弱成蟲並減少殺成蟲治療後的肺部病理變化。
它對非典型病原體高度有效，包括伯氏疏螺旋體（萊姆病）、鉤端螺旋體、立克次體、披衣菌、黴漿菌、巴爾通體和博德特氏菌。
作用機制
Doxycycline is a bacteriostatic antibiotic.
- Primary Mechanism: It reversibly binds to the 30S ribosomal subunit of susceptible organisms → prevents the binding of aminoacyl transfer-RNA to the mRNA-ribosome complex → inhibits bacterial protein synthesis.
- Secondary Mechanisms: It may also reversibly bind to 50S ribosomes and alter cytoplasmic membrane permeability.
- Anti-inflammatory/Immunomodulatory Effects: Beyond its antimicrobial properties, doxycycline inhibits matrix metalloproteinases (MMPs) and scavenges reactive oxygen species, which contributes to its efficacy in treating chronic inflammatory conditions (e.g., idiopathic rhinitis, arthritis).
安全性與警告
禁忌症
- Hypersensitivity to tetracyclines
- Intravenous administration in horses (associated with fatal cardiac arrhythmias)
- First half of pregnancy (can retard fetal skeletal development and discolor deciduous teeth, though less likely than other tetracyclines)
- Pregnant animals
- Animals with evidence of oesophagitis or dysphagia
不良反應
- Vomiting
- Diarrhea
- Anorexia
- Elevated liver enzymes (ALT, ALP)
- Esophageal strictures (especially in cats if dry-pilled)
- Superinfections (non-susceptible bacteria or fungi)
- Photosensitivity (reported in humans)
- Cardiac arrhythmias, collapse, and death (if given IV to horses)
- Nausea
- Diarrhoea
- Oesophagitis
- Oesophageal ulceration/stricture (especially in cats)
- Tooth discoloration (if given during tooth development, though risk is lower than other tetracyclines)
注意事項
WARNING: Do not administer IV to horses due to risk of fatal cardiac arrhythmias. Do not give IM or SC to any species.
- Esophageal Strictures: Highly associated with "dry pilling" in cats. Always follow oral solid doses with at least 6 mL of water or liquid.
- Hepatotoxicity: Use with caution in animals with significant liver dysfunction, as increases in hepatic enzymes have been documented.
- Pregnancy/Pediatric: Use with caution in pregnant and young animals due to potential for bone and teeth abnormalities, though doxycycline is safer than older tetracyclines.
- MDR1 Mutants: Safe to use; no dose alterations recommended for dogs with MDR1 mutations.
藥物相互作用
Chelates with divalent/trivalent cations, significantly decreasing doxycycline absorption. Give at least 1-2 hours apart.
May reduce gastrointestinal absorption of doxycycline.
Decreases tetracycline absorption. Give iron 3 hours before or 2 hours after doxycycline.
Bacteriostatic drugs (doxycycline) may theoretically interfere with the bactericidal activity of these antibiotics.
May decrease doxycycline half-life and reduce serum levels.
Tetracyclines may depress plasma prothrombin activity; anticoagulant dosage may need adjustment.
Reduced absorption of doxycycline
Reduced absorption of doxycycline
Reduced absorption of doxycycline
Reduced absorption of doxycycline
May increase doxycycline metabolism, decreasing plasma levels
Reduced absorption of doxycycline (though less marked than with water-soluble tetracyclines)
監測
- Clinical efficacy
- Adverse effects (GI upset)
- Liver enzymes (ALT, ALP) with prolonged use
- Clinical response to therapy
- Signs of dysphagia, regurgitation, or oesophagitis (especially in cats)
- Gastrointestinal upset
藥物動力學
半衰期
吸收
Well absorbed after oral administration (90-100% bioavailability in humans/monogastrics). Unlike other tetracyclines, absorption is only minimally reduced (by ~20%) by food or dairy products. However, in horses, feeding can reduce bioavailability to <5% due to high fiber content.
分佈
Highly lipid-soluble. Widely distributed to heart, kidney, lungs, muscle, pleural fluid, bronchial secretions, bile, saliva, synovial fluid, and aqueous/vitreous humor. Penetrates CSF, prostate, and eye better than other tetracyclines. Volume of distribution (Vd) in dogs is ~1.5 L/kg. Protein binding: 75-86% (dogs), 82% (horses), 93% (cattle/pigs/cats).
代謝
Partially inactivated in the intestine by chelate formation.
排除
Primarily excreted into the feces via non-biliary routes in an inactive form (chelate). Renal excretion accounts for only ~25% in dogs, and biliary excretion <5%. Does not accumulate in patients with renal dysfunction.
過量
Doxycycline is generally quite safe in mild overdose situations (except for IV administration in horses).
- Oral Overdose: Most likely associated with gastrointestinal disturbances (vomiting, anorexia, diarrhea).
- Treatment: Oral administration of divalent or trivalent cation antacids (e.g., calcium, magnesium, aluminum) can bind the drug in the gut and reduce GI distress. Monitor and replace fluids/electrolytes if severe emesis or diarrhea occurs.
- IV Overdose: Rapid intravenous injection has induced transient collapse and cardiac arrhythmias in several species, presumably due to chelation with intravascular calcium ions.
可用產品
劑型
- Delayed-Release Tablets and Capsules
- Powder for Oral Suspension
- Oral Syrup
- Injection (Lyophilized powder)
- Periodontal Gel (8.5%)
- 20 mg tablet
- 50 mg tablet
- 100 mg tablet
- 200 mg tablet
- 400 mg tablet
- Oral paste (named patient basis)
獸醫用
- Doxirobe® (Pfizer): Doxycycline gel 8.5% activity once mixed (for periodontal disease in dogs)
- Doxybactin 20 mg, 50 mg, 200 mg, 400 mg tablets
- Ronaxan 20 mg, 100 mg tablets
- Oral paste (named patient basis)
人用標示
- Periostat®, Alodox Convenience Kit®, Vibramycin®, Vibra-Tabs®, Oraxyl®, generic: Tablets & Capsules (20 mg, 50 mg, 100 mg)
- Doryx®, Oracea®: Delayed-Release Tablets & Capsules (40 mg, 75 mg, 100 mg, 150 mg)
- Monodox®, Adoxa®, generic: Tablets and Capsules (as monohydrate) (50 mg, 75 mg, 100 mg, 150 mg)
- Vibramycin®, Doxycycline (Teva): Powder for Oral Suspension (5 mg/mL after reconstitution)
- Vibramycin®: Oral Syrup (as calcium salt) (10 mg/mL)
- Atridox®: Injection (42.5 mg in vials)
- Doxy®-100 & -200, generic: Lyophilized Powder for Injection (100 mg, 200 mg)
各地核准狀態
POM-V
POM-V
暫無法規資料: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
儲存與穩定性
Tablets and capsules should be stored in tight, light-resistant containers at <30°C (preferably 15-30°C). Reconstituted monohydrate oral suspension is stable for 14 days at room temperature. Compounded oral suspensions degrade rapidly between 7-14 days even if refrigerated. Tablets mixed with water/food lose >10% potency after 24 hours. Reconstituted hyclate injection (0.1-1 mg/mL) is stable for 72 hours refrigerated.
飼主須知
- 貓咪的重大警告： 絕對不要對貓咪進行「乾吞藥丸」。多西環素的膠囊或錠劑可能會卡在食道中，造成嚴重且永久性的損傷（食道狹窄）。餵食固體藥物後，務必給予至少 6 毫升（略多於一茶匙）的水或液體。餵藥後在貓咪嘴唇上塗抹少許奶油可誘發唾液分泌，幫助藥丸順利吞下。
- 食物與乳製品： 多西環素可與食物一起或空腹服用。與食物同服有助於預防腸胃不適。與舊型四環黴素不同，牛奶或乳製品不會顯著阻礙多西環素的吸收。
- 陽光照射： 在極少數情況下，此藥物可能會使皮膚對陽光更加敏感。
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