阿昔洛韋
**阿昔洛韋 (Acyclovir)** 是一種合成的嘌呤核苷類似物，在獸醫學中主要用於對抗特定皰疹病毒的感染。 主要臨床應用包括： * **禽類醫學**：用於治療和預防**帕切科氏病 (Pacheco's disease)**（一種對鳥類具高度致命性的皰疹病毒感染）。 * **貓科醫學**：用於控制**貓皰疹病毒-1型 (FHV-1)** 感染，特別是角膜或結膜的病變。*臨床提示：與泛昔洛韋 (famciclovir)、更昔洛韋 (ganciclovir) 或西多福韋 (cidofovir) 等較新的抗病毒藥物相比，它對 FHV-1 的活性較弱，且在貓身上引發全身性毒性的風險較高。* * **馬科醫學**：研究用於治療**馬皰疹病毒-1型 (EHV-1)** 引起的脊髓腦病，但由於其在馬體內的口服生物利用度極低（<4%），使得治療效果面臨挑戰。 雖然在人類醫學中效果顯著，但其在獸醫物種中的應用常受限於藥代動力學的差異、某些物種（如馬）口服吸收不良，以及潛在的毒性（如貓的腎毒性和骨髓抑制）。
作用機制: Acyclovir is a prodrug that requires activation by viral enzymes, making it highly specific to infected cells. 1. **Viral Entry**: Acyclovir enters the virus-infected cell. 2. **Initial Phosphorylation**: It is preferentially phosphorylated by **viral thymidine kinase** into acyclovir monophosphate. 3. **Subsequent Phosphorylation**: Host cell kinases further convert it into the active form, **acyclovir triphosphate**. 4. **DNA Chain Termination**: Acyclovir triphosphate acts as a competitive inhibitor of **viral DNA polymerase**. It incorporates into the growing viral DNA chain → lacks the 3'-hydroxyl group needed for further elongation → causes **premature DNA chain termination** and halts viral replication.
各物種劑量
- Herpesvirus-1 infections · 10-25 mg/kg PO twice daily · PO · q12h · Never begin therapy until diagnostic evaluation is completed. May be toxic in cats; monitor CBC every 2-3 weeks.
- EHV-1 outbreaks (prevention or treatment) · 10 mg/kg PO 5 times daily or 20 mg/kg PO q8h · PO · 5 times daily or q8h · Although efficacy is undetermined, anecdotal use may have had some efficacy. However, the drug's very low oral bioavailability suggests that oral dosing is unlikely to be of much benefit.
- Treatment of Pacheco's Disease · 80 mg/kg PO q8h or 40 mg/kg q8h IM · PO/IM · q8h · Maximum 72 hours for IM · Do not use parenterally for more than 72 hours as it can cause tissue necrosis at site of injection.
- Treatment of Pacheco's Disease · 80 mg/kg in oral suspension once daily PO; mix suspension with peanut butter or add to drinking water 50 mg in 4 oz of water · PO · q24h · 7-14 days
- Individual treatment · 80 mg/kg PO or IM twice daily · PO/IM · q12h
- Prophylaxis (Exposed birds) · 25 mg/kg IM once, then acyclovir is added to drinking water at 1 mg/mL and to the food at 400 mg/quart of seed · IM, then PO · Once IM, then continuous PO · Minimum of 7 days · Give IM with caution as it is very irritating.
- Prophylaxis (Quaker parrots) · 80 mg/kg q8h · PO (gavage) · q8h · 7 days
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。
給藥途徑
禁忌症
- Dehydrated states
- Pre-existing renal function impairment
- Hypersensitivity to acyclovir or related antivirals
- Pre-existing neurologic deficits
- Previous neurologic reactions to other cytotoxic drugs
不良反應
- Thrombophlebitis (with parenteral use)
- Acute renal failure
- Encephalopathologic changes (rare)
- Gastrointestinal disturbances (vomiting, diarrhea)
- Leukopenia (cats)
- Anemia (cats)
- Tissue necrosis (if given IM for >72 hours in birds)
藥物相互作用
- Nephrotoxic medications (e.g., Amphotericin B, Aminoglycosides) · Concomitant administration with IV acyclovir may increase the potential for nephrotoxicity. Amphotericin B may potentiate antiviral effects but significantly increases nephrotoxic risk.
- Zidovudine · Concomitant use may cause additional CNS depression.
監測
- Renal function tests (BUN, Serum Creatinine) with prolonged or IV therapy
- Complete Blood Count (CBC) every 2-3 weeks in cats to monitor for leukopenia and anemia
- Hydration status
過量
Acute oral overdosage is unlikely to cause significant toxicity. * **Clinical Signs**: Gastrointestinal signs (vomiting, diarrhea, lethargy) predominate. Renal failure is possible with higher doses due to drug crystallization in the renal tubules. Crystalluria and elevated renal values occurred at 188.7 mg/kg in a dog. * **Treatment**: Consider gastrointestinal decontamination at doses of **150 mg/kg or higher**. Below 150 mg/kg, manage symptomatically as GI signs will likely predominate. Ensure adequate hydration to maintain urine flow and prevent crystalluria.
VetSheet 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。