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ジドブジン

Zidovudine

3'-azido-2',3'-dideoxythymidine

抗レトロウイルス薬 (ヌクレオシド系逆転写酵素阻害薬)POSCIV猫

別名: Retrovir · AZT · ZDV · azidodeoxythymidine · 3'-azido-2',3'-dideoxythymidine · azidothymidine · BW-A509U · BW-509U · compound-S · zidovudinum

VetSheet 獣医チームが監修更新日 2026年4月5日エビデンスに基づく獣医学リファレンス

5-10 mg/kg PO or SC q12hPO, SC· q12h
— 🐈

用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。

動物種別用量

🌎 NA — North America🌍 EU — Europe

猫

適応用量経路頻度期間地域
Adjunctive therapy of FeLV and FIV5-10 mg/kg PO or SC q12hPO, SCq12h—🌎 NA
Adjunctive therapy of FeLV and FIV5-10 mg PO or SC q12hPO, SCq12h—🌎 NA
FeLV5 mg/kg PO or SC q12hPO, SCq12h—🌎 NA
FIV encephalopathy20 mg/kg PO q12hPOq12h—🌎 NA
  • Adjunctive therapy of FeLV and FIV: Higher dose should be used carefully as side effects can develop. For SC injection, dilute lyophilized product in isotonic sodium chloride to prevent local irritation. For PO, syrup or gelatin capsules can be used.
  • Adjunctive therapy of FeLV and FIV: Note: Dose is in mg per cat, not mg/kg. Higher dose should be carefully used in FeLV-infected cats because side effects, particularly non-regenerative anemia, can develop.
  • FeLV: If giving SC, dilute in sterile normal saline to prevent local irritation. Check CBC weekly the first month.

用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。

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概要

ジドブジン（AZT）は​ヌクレオシド系逆転写酵素阻害薬（NRTI）​であり、獣医学においては主に猫免疫不全ウイルス（FIV）や猫白血病ウイルス（FeLV）の補助治療として使用されます。

  • ​臨床的有用性​：感染した猫のウイルス量を減らし、臨床症状（口内炎や神経症状など）を改善する可能性がありますが、完治させるものではなく、疾患の長期的な自然経過を大きく変えるものではありません。
  • ​臨床のポイント​：レトロウイルスは宿主のゲノムに組み込まれるため、ジドブジンのようなNRTIは、すでに感染した細胞を排除するのではなく、新しい細胞への感染を防ぐのに最も効果的です。

作用機序

Zidovudine is a synthetic thymidine analogue.

  • Mechanism: It is converted in vivo by cellular kinases into its active metabolite, zidovudine triphosphate.
  • Pathway: Zidovudine triphosphate competes with natural thymidine triphosphate for incorporation into viral DNA by viral RNA-directed DNA polymerase (→ reverse transcriptase).
  • Effect: Because zidovudine lacks a 3'-OH group, its incorporation prevents the formation of phosphodiester linkages, leading to DNA chain termination and a virustatic effect against retroviruses.
  • It also possesses some activity against gram-negative bacteria and can exhibit host cell cytotoxicity (particularly in rapidly dividing cells like bone marrow).

安全性・警告

禁忌

  • Patients with a history of life-threatening hypersensitivity reactions to zidovudine

有害事象

  • Non-regenerative anemia (most common in cats, dose-dependent)
  • Reductions in RBCs, PCV, and hemoglobin
  • Diarrhea
  • Weakness
  • Granulocytopenia (reported in humans)
  • Gastrointestinal effects

注意事項

Bone Marrow Suppression: Use with extreme caution in patients with pre-existing bone marrow dysfunction. Cats with bone marrow suppression should generally not be treated with zidovudine.

  • Organ Dysfunction: Dosage adjustment may be necessary in cats with renal or hepatic dysfunction.
  • Pregnancy: FDA Category C for use during pregnancy (animal studies show adverse fetal effects, but adequate human studies are lacking).
  • Lactation: Excreted in milk; clinical significance for nursing offspring is unclear.

医薬品相互作用

Azole Antifungals (e.g., ketoconazole)

May increase zidovudine levels

Atovaquone

May increase zidovudine levels

Doxorubicin

May antagonize each other's effects; avoid concurrent use. Also increases risk of hematologic toxicity.

Interferon alfa

Increased risk for hematologic and hepatotoxicity

Probenecid

May increase zidovudine levels

Myelo-/Cytotoxic Drugs (e.g., chloramphenicol, flucytosine, vincristine, vinblastine)

Administered with zidovudine may increase the risk of hematologic toxicity

Rifampin

May decrease blood levels (AUC) of zidovudine

監視

  • CBC (Complete Blood Count): Weekly for the first month of treatment (non-regenerative anemia is common, especially at higher doses). If stable, monthly checks are sufficient.
  • Hematocrit: If PCV drops below 20%, treatment should be discontinued (anemia usually resolves within a few days).
  • CD4/CD8 ratios (if possible)
  • Clinical efficacy and improvement of signs

薬物動態

半減期

猫1.5 hours

吸収

Well absorbed after oral administration. In cats, oral bioavailability is approximately 95%. When administered with food, peak levels may be decreased, but total AUC is generally unaffected. Peak levels occur about 1 hour post-dosing in cats.

分布

Widely distributed throughout the body, including penetration into the cerebrospinal fluid (CSF). It is only marginally bound to plasma proteins.

代謝

Rapidly metabolized in vivo.

消失

Excreted primarily in the urine.

過剰投与

Human adults and children have survived massive oral overdoses (up to 50 grams) without permanent sequelae.

  • Clinical Signs: Vomiting and transient hematologic effects (e.g., bone marrow suppression) are the most consistent adverse effects reported with acute overdoses.
  • Management: Treatment is largely supportive and symptomatic, focusing on gastrointestinal decontamination if caught early, and monitoring hematologic parameters.

製品

製剤

  • Tablets
  • Capsules
  • Syrup
  • Injection solution

ヒト用医薬品

  • Zidovudine Oral Tablets: 300 mg (Retrovir, generic)
  • Zidovudine Oral Capsules: 100 mg (Retrovir, generic)
  • Zidovudine Oral Syrup: 50 mg/5 mL in 240 mL (Retrovir, generic)
  • Zidovudine Injection Solution: 10 mg/mL in 20 mL single-use vials (Retrovir)

規制ステータス

規制データなし: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU

保管・安定性

Oral tablets, capsules, and syrup should be stored at room temperature. Protect from heat, light, and moisture. Injection (for IV infusion) should be stored at room temperature and protected from light.

飼主向け情報

  • ​実験的療法​：この薬は、猫のウイルス感染症に対する「実験的」または適応外の治療法と見なされています。
  • ​厳密な服薬遵守​：ウイルスに対する効果を維持するため、獣医師の指示通りに正確に投与する必要があります。
  • ​必須の血液検査​：この薬は重篤な貧血を引き起こす可能性があるため、定期的な血液検査（最初は通常毎週）のための通院が絶対に必要です。
  • ​副作用への注意​：猫が異常にぐったりしている、無気力、歯茎が白い、または食欲がない場合は、すぐに獣医師に連絡してください。

VetSheet医薬品リファレンスは獣医専門家の臨床意思決定支援を目的としており、専門的判断または製造業者の最新医薬品情報の代替にはなりません。