Ganciclovir
Also known as: Virgan · Ganciclovirum
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Ocular feline herpesvirus-1 (FHV-1) infections | Apply small amount to affected eye | topical | q4-6h | maximum 3 weeks | 🌍 EU |
- Ocular feline herpesvirus-1 (FHV-1) infections: In refractory and severe cases, combined therapy can be used.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Ganciclovir is an antiviral agent used primarily for the management of ocular feline herpesvirus-1 (FHV-1) infections. In vitro studies indicate that ganciclovir is at least 10 times more effective against FHV-1 than aciclovir.
Clinical Warning: It cannot eradicate latent viral infections. While anecdotal reports of its topical use are promising, neither the safety nor the pharmacokinetics has been fully reported in cats. In refractory and severe cases of FHV-1 ulceration, combined therapy including topical or systemic antiviral medication can be used.
Mechanism of action
Ganciclovir inhibits viral replication by targeting viral DNA polymerase. It depends on viral thymidine kinase for initial phosphorylation → converted to active ganciclovir triphosphate by cellular enzymes → competitive inhibition of viral DNA polymerase → termination of viral DNA chain elongation.
Safety & warnings
Adverse effects
- Ocular irritation
Precautions
Normal handling precautions should be observed.
Treatment should not be continued for more than 3 weeks. If ocular irritation develops, the frequency of application should be reduced.
Monitoring
- Resolution of clinical ocular signs (e.g., healing of corneal ulcers)
- Signs of ocular irritation or discomfort
Pharmacokinetics
Absorption
No information available in cats.
Distribution
No information available in cats.
Metabolism
No information available in cats.
Elimination
No information available in cats.
Overdose
No specific information available. Overdose via topical ophthalmic route is unlikely to cause systemic toxicity, but may increase the risk of severe ocular irritation.
Available products
Formulations
- 0.15% eye gel
Human-labeled
- Virgan 0.15% eye gel (5 g tube)
Regulatory status
Human authorized product used off-label under the cascade in veterinary medicine.
Human authorized product (POM) used off-label under the cascade.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Normal precautions should be observed. Store at room temperature unless otherwise directed by the manufacturer.
Client information
Wash your hands thoroughly before and after applying the eye gel. Apply exactly as directed by your veterinarian, usually every 4 to 6 hours.
Do not use this medication for more than 3 weeks.
Watch for signs of eye irritation such as increased redness, squinting, or rubbing of the eye. If this occurs, contact your veterinarian as the frequency of application may need to be reduced. Note: This medication helps manage the active virus but does not cure the underlying latent herpesvirus infection.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.