What is Valacyclovir used for?

Valacyclovir is indicated for: herpesvirus.

Which species have cited Valacyclovir dosing data?

Valacyclovir dosing in the ExoticRx formulary covers 2 species: Cat (Domestic), Eastern Box Turtle.

Is Valacyclovir a controlled substance?

Valacyclovir is not federally scheduled in the US. Controlled-drug status differs by country — verify your local rules.

What are the side effects of Valacyclovir?

Reported side effects, adverse reactions, and contraindications for Valacyclovir: TOXIC TO CATS — causes acute hepatic necrosis and fatal bone marrow suppression. Dogs tolerate well. Ensure adequate hydration.

Valacyclovir

US brand names:Valtrex

Calculate dosage

Sourced from published veterinary references. Awaiting credentialed clinical reviewer — our editorial process.

Valacyclovir is dosed at 40 mg/kg PO q24h in eastern box turtles, per 4. Allender MC, Mitchell MA, Yarborough J, et al. Pharmocokinetics of a single oral dose of acyclovir and valacyclovir in North American box turtles (Terrapene sp.). J Vet Pharmacol Therap. 2012;36:205-208. — Source: Mader's Reptile and Amphibian Medicine and Surgery, 3rd Ed, p.1404. Verify against current literature before clinical use.

Drug Class

Antiviral

Routes

Indications

Warnings from the source rows

DO NOT USE IN CATS

herpesvirus

Mechanism of Action

Prodrug rapidly converted to acyclovir. Triphosphorylated form inhibits viral DNA polymerase and causes chain termination. Active against herpesviruses.

Side effects & warnings

TOXIC TO CATS — causes acute hepatic necrosis and fatal bone marrow suppression. Dogs tolerate well. Ensure adequate hydration.

Evidence levels across 2 dose rules

Strong×1Weak×1

Each ExoticRx dose rule is graded by the strength of its primary evidence — see the editorial process.

Sample dosing (1 of 2 cited rules)

A dog/cat sample is shown here. Cited dosing for all 2 species — reptiles, birds, pocket pets, livestock, and equine — is free on the per-species pages above. Pro adds the weight-based calculator for every species.

Species	Route	Dose	Frequency	Evidence	Source
Cat (Domestic)	PO	CONTRAINDICATED IN CATS	N/A	Strong	Nasisse MP, Dorman DC, Jamison KC, Weigler BJ, Hawkins EC, Stevens JB. Effects of valacyclovir in cats infected with feline herpesvivus 1. Am J Vet Res. 1997;58:1141-1144. doi:10.2460/ajvr.1997.58.10.1141 — Plumb's 10th ed printed p.1289, Valacyclovir monograph spanning p.1289-1290.

Backed by 2 published sourcesShow

· 4. Allender MC, Mitchell MA, Yarborough J, et al. Pharmocokinetics of a single oral dose of acyclovir and valacyclovir in North American box turtles (Terrapene sp.). J Vet Pharmacol Therap. 2012;36:205-208. — Source: Mader's Reptile and Amphibian Medicine and Surgery, 3rd Ed, p.1404
· Nasisse MP, Dorman DC, Jamison KC, Weigler BJ, Hawkins EC, Stevens JB. Effects of valacyclovir in cats infected with feline herpesvivus 1. Am J Vet Res. 1997;58:1141-1144. doi:10.2460/ajvr.1997.58.10.1141 — Plumb's 10th ed printed p.1289, Valacyclovir monograph spanning p.1289-1290.

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