Famciclovir
Famvir (famciclovir) is the best-in-class oral nucleoside analogue widely used off-label by veterinarians for certain canine herpesvirus infections because of its established antiviral mechanism and availability in human and generic formulations. It holds a cost advantage over biologics like interferon omega due to generic supply and straightforward oral dosing, while offering a more directly virus-targeted approach than immune modulators and supplements on this list. Compared with oseltamivir, famciclovir targets DNA herpesviruses rather than influenza-type viruses, making it technically preferable for herpes-related canine cases when prescribed by a veterinarian.
Stops viral replication
Oral dosing convenience
Stops viral replication
Oral dosing convenience
Review Summary
"Owners and veterinarians report famciclovir can reduce viral symptoms and is generally well tolerated in dogs, but it is often used off-label, can be expensive, and results vary between patients."
Stealthy symptom buster
Oral antiviral prodrug (converted to penciclovir) used to treat DNA viral infections including canine herpes-related disease.
Stealthy symptom buster
Oral antiviral prodrug (converted to penciclovir) used to treat DNA viral infections including canine herpes-related disease.
Increased Safety & Security
Time-Saving Convenience
Famvir (famciclovir) is the best-in-class oral nucleoside analogue widely used off-label by veterinarians for certain canine herpesvirus infections because of its established antiviral mechanism and availability in human and generic formulations. It holds a cost advantage over biologics like interferon omega due to generic supply and straightforward oral dosing, while offering a more directly virus-targeted approach than immune modulators and supplements on this list. Compared with oseltamivir, famciclovir targets DNA herpesviruses rather than influenza-type viruses, making it technically preferable for herpes-related canine cases when prescribed by a veterinarian.
Stops viral replication
Oral dosing convenience
Stealthy symptom buster
Oral antiviral prodrug (converted to penciclovir) used to treat DNA viral infections including canine herpes-related disease.
Typically dispensed by prescription and often compounded to canine-appropriate doses by veterinary pharmacies.
Stops viral replication
Oral dosing convenience
Stealthy symptom buster
Oral antiviral prodrug (converted to penciclovir) used to treat DNA viral infections including canine herpes-related disease.
Typically dispensed by prescription and often compounded to canine-appropriate doses by veterinary pharmacies.
$80-300 USD
Lysine
VetriScience Lysine is a leading veterinary supplement formulation containing gal-lysine marketed to support antiviral management as an adjunct therapy; it is inexpensive, broadly available, and commonly used by clinicians as part of multi-modal supportive care. While not a prescription antiviral itself, its low cost and OTC accessibility make it a financially attractive companion product compared with prescription antivirals, although clinical evidence in dogs is limited relative to prescription drugs like famciclovir or interferon omega. Its role is largely supportive rather than curative, distinguishing it from direct-acting antivirals and recombinant interferons on this list.
Amino acid boost
Palatable chewable
Amino acid boost
Palatable chewable
Review Summary
"Most users find generic lysine provides little to no consistent benefit for canine viral infections; some use it preventively and occasionally note mild improvement, but clinical evidence is weak."
Immune-sidekick wink
Non-prescription amino acid supplement marketed to support immune function and reduce herpesvirus replication in some species.
Immune-sidekick wink
Non-prescription amino acid supplement marketed to support immune function and reduce herpesvirus replication in some species.
Increased Safety & Security
VetriScience Lysine is a leading veterinary supplement formulation containing gal-lysine marketed to support antiviral management as an adjunct therapy; it is inexpensive, broadly available, and commonly used by clinicians as part of multi-modal supportive care. While not a prescription antiviral itself, its low cost and OTC accessibility make it a financially attractive companion product compared with prescription antivirals, although clinical evidence in dogs is limited relative to prescription drugs like famciclovir or interferon omega. Its role is largely supportive rather than curative, distinguishing it from direct-acting antivirals and recombinant interferons on this list.
Amino acid boost
Palatable chewable
Immune-sidekick wink
Non-prescription amino acid supplement marketed to support immune function and reduce herpesvirus replication in some species.
Available as chewables, powders, or capsules for easy daily dosing alongside veterinary therapy.
Amino acid boost
Palatable chewable
Immune-sidekick wink
Non-prescription amino acid supplement marketed to support immune function and reduce herpesvirus replication in some species.
Available as chewables, powders, or capsules for easy daily dosing alongside veterinary therapy.
$10-40 USD
Interferon Omega
Virbagen Omega (recombinant interferon omega) is the market-leading licensed interferon product used in veterinary medicine for certain viral diseases in cats and dogs, prized for its host-targeted, immunomodulatory antiviral action when direct antivirals are insufficient. It is typically prescription-only and more costly than small-molecule antivirals or amino-acid supplements, but offers a unique mechanism that can be effective against a broader range of viral pathogens and in refractory cases where virus-directed drugs like famciclovir or oseltamivir may be less useful. Financially and technically, Virbagen’s strength is in providing a biologic option for difficult-to-treat infections, offsetting higher per-treatment costs with clinical versatility.
Potent antiviral protein
Injectable therapy option
Potent antiviral protein
Injectable therapy option
Review Summary
"Interferon omega receives strong praise from vets and many owners for producing meaningful improvement in some viral cases with good tolerability, though it is costly and not always easy to obtain."
Immune system whisperer
Recombinant interferon omega is a veterinary antiviral/immunomodulator prescribed for certain viral infections and immune support.
Immune system whisperer
Recombinant interferon omega is a veterinary antiviral/immunomodulator prescribed for certain viral infections and immune support.
Increased Safety & Security
Time-Saving Convenience
Virbagen Omega (recombinant interferon omega) is the market-leading licensed interferon product used in veterinary medicine for certain viral diseases in cats and dogs, prized for its host-targeted, immunomodulatory antiviral action when direct antivirals are insufficient. It is typically prescription-only and more costly than small-molecule antivirals or amino-acid supplements, but offers a unique mechanism that can be effective against a broader range of viral pathogens and in refractory cases where virus-directed drugs like famciclovir or oseltamivir may be less useful. Financially and technically, Virbagen’s strength is in providing a biologic option for difficult-to-treat infections, offsetting higher per-treatment costs with clinical versatility.
Potent antiviral protein
Injectable therapy option
Immune system whisperer
Recombinant interferon omega is a veterinary antiviral/immunomodulator prescribed for certain viral infections and immune support.
Administered by injection under veterinary supervision and typically costly due to biologic manufacturing and dosing needs.
Potent antiviral protein
Injectable therapy option
Immune system whisperer
Recombinant interferon omega is a veterinary antiviral/immunomodulator prescribed for certain viral infections and immune support.
Administered by injection under veterinary supervision and typically costly due to biologic manufacturing and dosing needs.
$300-900 USD
Oseltamivir (Tamiflu)
Tamiflu (oseltamivir) is the widely recognized neuraminidase inhibitor used for influenza that is sometimes prescribed off-label by veterinarians for canine influenza or suspected orthomyxovirus exposures due to its broad human-market availability and oral dosing convenience. Its market-leading presence in human medicine translates into strong generic supply chains and relatively lower cost per dose versus proprietary biologics, but its antiviral mechanism is specific to influenza-like viruses and is not appropriate for canine herpesviruses addressed by drugs like famciclovir. Clinicians weigh Tamiflu’s availability and oral formulation against limited veterinary-specific efficacy data when considering it for canine antiviral protocols.
Blocks viral release
Oral capsule use
Blocks viral release
Oral capsule use
Review Summary
"Oseltamivir (Tamiflu) is often used off-label during parvovirus outbreaks and reviewed as a helpful adjunct in many cases, but results are mixed and it is not a standalone cure; dosing and evidence are debated."
Flu-fighter with swagger
Oral neuraminidase inhibitor (Tamiflu®) used off-label in veterinary medicine for certain viral illnesses; prescription required.
Flu-fighter with swagger
Oral neuraminidase inhibitor (Tamiflu®) used off-label in veterinary medicine for certain viral illnesses; prescription required.
Increased Safety & Security
Time-Saving Convenience
Tamiflu (oseltamivir) is the widely recognized neuraminidase inhibitor used for influenza that is sometimes prescribed off-label by veterinarians for canine influenza or suspected orthomyxovirus exposures due to its broad human-market availability and oral dosing convenience. Its market-leading presence in human medicine translates into strong generic supply chains and relatively lower cost per dose versus proprietary biologics, but its antiviral mechanism is specific to influenza-like viruses and is not appropriate for canine herpesviruses addressed by drugs like famciclovir. Clinicians weigh Tamiflu’s availability and oral formulation against limited veterinary-specific efficacy data when considering it for canine antiviral protocols.
Blocks viral release
Oral capsule use
Flu-fighter with swagger
Oral neuraminidase inhibitor (Tamiflu®) used off-label in veterinary medicine for certain viral illnesses; prescription required.
Primarily an influenza drug in humans; veterinary use is off-label and should be directed by a veterinarian with dosing adjustments.
Blocks viral release
Oral capsule use
Flu-fighter with swagger
Oral neuraminidase inhibitor (Tamiflu®) used off-label in veterinary medicine for certain viral illnesses; prescription required.
Primarily an influenza drug in humans; veterinary use is off-label and should be directed by a veterinarian with dosing adjustments.
$40-160 USD
gal-Lysine HCl
NOW Foods gal-Lysine HCl is a pharmaceutical-grade crystalline gal-lysine hydrochloride product often used where precise, standardized dosing of lysine is desired as an adjunct in veterinary care; it is a market leader among bulk gal-lysine ingredients due to consistent purity and competitive pricing. Technically, gal-Lysine HCl offers a more measurable and pure ingredient for compounding or dosing than blended lysine supplements, making it financially efficient for clinics that require large-volume or weight-based administration compared with proprietary lysine formulations. Although not a prescription antiviral by itself, its standardized chemistry complements prescription antiviral regimens when used under veterinary guidance.
Pure lysine form
Measure-friendly powder
Pure lysine form
Measure-friendly powder
Review Summary
"gal‑Lysine HCl, the purified salt form of lysine, yields similar user feedback to generic lysine—mostly negligible effects on active infections though some owners report reduced recurrence of symptoms."
Tangy tail-wagger
Pharmaceutical-grade gal-lysine hydrochloride is a concentrated, pure form of lysine used as a dietary supplement.
Tangy tail-wagger
Pharmaceutical-grade gal-lysine hydrochloride is a concentrated, pure form of lysine used as a dietary supplement.
Increased Safety & Security
NOW Foods gal-Lysine HCl is a pharmaceutical-grade crystalline gal-lysine hydrochloride product often used where precise, standardized dosing of lysine is desired as an adjunct in veterinary care; it is a market leader among bulk gal-lysine ingredients due to consistent purity and competitive pricing. Technically, gal-Lysine HCl offers a more measurable and pure ingredient for compounding or dosing than blended lysine supplements, making it financially efficient for clinics that require large-volume or weight-based administration compared with proprietary lysine formulations. Although not a prescription antiviral by itself, its standardized chemistry complements prescription antiviral regimens when used under veterinary guidance.
Pure lysine form
Measure-friendly powder
Tangy tail-wagger
Pharmaceutical-grade gal-lysine hydrochloride is a concentrated, pure form of lysine used as a dietary supplement.
Often sold in powder or capsule form for precise dosing and is available without prescription.
Pure lysine form
Measure-friendly powder
Tangy tail-wagger
Pharmaceutical-grade gal-lysine hydrochloride is a concentrated, pure form of lysine used as a dietary supplement.
Often sold in powder or capsule form for precise dosing and is available without prescription.
$15-50 USD