Acyclovir
Also known as: Zovirax, Acic, Aciclobene, Aciclotyrol, Acivir, Acyrax, Cicloviral, Geavir, Herpotern, Isavir, Nycovir, Supraviran, Viclovir, Virherpes, Viroxy, Xorox
**Acyclovir** is an antiviral medication used to treat specific viral infections, such as herpesvirus. * **Administration**: Give exactly as directed by your veterinarian. Do not skip doses, as maintaining consistent drug levels is crucial for fighting the virus. * **Hydration is Key**: Ensure your pet always has access to plenty of fresh drinking water. This drug is processed by the kidneys, and good hydration helps prevent kidney damage. * **Side Effects**: The most common side effects are stomach upset (vomiting, diarrhea) and lethargy. * **Special Note for Cats**: Cats are more sensitive to this medication. It can temporarily lower their white and red blood cell counts. Watch closely for signs of extreme weakness, pale gums, or fever, and contact your vet immediately if these occur. Your vet will likely require regular blood tests to monitor your cat safely. * **Storage**: Store at room temperature away from light and moisture.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- Herpesvirus-1 infections
- EHV-1 outbreaks (prevention or treatment)
- Treatment of Pacheco's Disease
- Treatment of Pacheco's Disease
- Individual treatment
- Prophylaxis (Exposed birds)
- Prophylaxis (Quaker parrots)
How it is given
Possible side effects
- 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)
Cautions & contraindications
- Dehydrated states
- Pre-existing renal function impairment
- Hypersensitivity to acyclovir or related antivirals
- Pre-existing neurologic deficits
- Previous neurologic reactions to other cytotoxic drugs
- > **Renal Warning**: Acyclovir is primarily excreted by the kidneys and can precipitate in renal tubules, especially if given rapidly IV or in dehydrated patients. Ensure adequate hydration during therapy. * **Feline Toxicity**: Cats are particularly sensitive to bone marrow suppression (leukopenia, anemia) from acyclovir. Use with extreme caution and monitor CBCs closely. * **Tissue Irritation**: IM injections can be highly irritating and may cause tissue necrosis if used for more than 72 hours (noted in avian species). * **Pregnancy/Nursing**: May be fetotoxic at high dosages (FDA Category C). It crosses the placenta and is excreted in milk at concentrations higher than maternal plasma. Use with caution in nursing patients. * **Renal Impairment**: Dosage reduction is required in patients with renal insufficiency.
Drug interactions
- 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.
Frequently asked questions
What is Acyclovir used for in pets?
**Acyclovir** is an antiviral medication used to treat specific viral infections, such as herpesvirus. * **Administration**: Give exactly as directed by your veterinarian. Do not skip doses, as maintaining consistent drug levels is crucial for fighting the virus. * **Hydration is Key**: Ensure your pet always has access to plenty of fresh drinking water. This drug is processed by the kidneys, and good hydration helps prevent kidney damage. * **Side Effects**: The most common side effects are stomach upset (vomiting, diarrhea) and lethargy. * **Special Note for Cats**: Cats are more sensitive to this medication. It can temporarily lower their white and red blood cell counts. Watch closely for signs of extreme weakness, pale gums, or fever, and contact your vet immediately if these occur. Your vet will likely require regular blood tests to monitor your cat safely. * **Storage**: Store at room temperature away from light and moisture.
Is Acyclovir safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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