Prescribing overview
Zenrelia treats allergic itch and atopic dermatitis in adult dogs. Immunomodulation requires infection assessment and vaccination planning; the current label retains an inadequate-vaccine-response warning.
Key prescribing checks
- Current U.S. labeling still warns about inadequate vaccine response and prohibits vaccination during treatment. A veterinarian must plan treatment interruption using the current label.
- The earlier fatal vaccine-induced disease language was removed; that revision did not remove all vaccine precautions.
- Do not use in dogs with serious infections. Assess recurrent infection, demodicosis and neoplasia history and monitor for new illness.
- Review blood-count monitoring and concurrent immunosuppressants; safety with glucocorticoids, cyclosporine and other systemic immunosuppressants has not been established.
Uses by species
Approval and evidence apply to the named product, species, route and indication. An extra-label use requires its own prescribing assessment; a human indication is not an animal approval.
Dogs ≥12 months
FDA-approved Zenrelia indicationsAllergic-dermatitis pruritus; atopic dermatitis
Do not use with serious infection.
Use / indication source ↗Pharmacology & pharmacokinetics
Mechanism and clinical role
Nonselective JAK inhibitor, including JAK1/JAK2/TYK2, reducing cytokine signaling; not an antihistamine or corticosteroid.
Absorption, distribution, metabolism and elimination
Dogs: oral bioavailability 80% fed/60% fasted; intravenous terminal half-life 3.6 hours; biliary/fecal excretion.
SAFETY REFERENCE · PRODUCT & SPECIES SPECIFIC
Contraindications & cautions
Contraindications identify circumstances where the source says a product should not be used. Precautions call for assessment or monitoring. Interactions identify combinations to review. They are distinct categories; this summary does not replace a full interaction check or the current product label.
Zenrelia
U.S. canine oral-tablet label.
Contraindications · when not to use
- No formal contraindications section is supplied; substantial do-not-use warnings remain.
Precautions & monitoring
- Warnings prohibit use with serious infection or below twelve months of age. Review infection, demodicosis/neoplasia history and blood-count effects.
Safety sources checked: . Selected label information; independent veterinary or veterinary-pharmacy review remains pending. A label for dogs, cats, horses or humans does not establish safety for another species.
Adverse effects
Vomiting, diarrhea, lethargy, neutropenia, infections and liver-enzyme elevations are described.
These are selected source-reported effects, not incidence estimates or an exhaustive list. Spontaneous postmarketing reports do not by themselves establish frequency or causality.
Dosing & administration
| Species & indication | Labeled regimen | Eligibility & source |
|---|---|---|
| Dogs ≥12 months; label chart starts at 3 kg (6.6 lb)Labeled allergic itch/atopic dermatitisZenrelia tablets | 0.6–0.8 mg/kg (0.27–0.36 mg/lb) Oral · Once daily No fixed course stated; clinician-directed reassessment | With/without food; use label weight-band tablet schedule. Verify full dosing label ↗ |
For vaccination, stop at least 28 days to 3 months beforehand and withhold at least 28 days afterward; veterinarian must plan interruption.
Extra-label prescribing and food-animal residue requirements are separate from labeled regimens. FDA extra-label-use guidance ↗
Drug & supplement interactions
This is a selected interaction reference, not an automated or comprehensive combination checker. Reconcile prescription drugs, nonprescription products, supplements and recent treatment changes.
Zenrelia
U.S. canine oral-tablet label.
- Do not vaccinate during treatment; use current label interruption periods. Combination safety with systemic immunosuppressants is unestablished.
Monitoring
Review infection, neoplasia and demodicosis; monitor blood counts.
Client counseling
Do not vaccinate during treatment; report new illness.
This section supports the veterinary team's discharge discussion; it does not replace the product’s Client Information Sheet where one is required.
Storage & handling
Wash hands after handling tablets; keep inaccessible to children.
Brands, formulations & ingredient identity
Active ingredients
Ilunocitinib
Zenrelia contains ilunocitinib, not Apoquel’s oclacitinib. Both are JAK inhibitors, but they are different medications with distinct labeling.
Use current U.S. prescribing information: vaccination warnings have changed since the initial approval. Older summaries can be misleading.
Shared ingredients do not establish interchangeable concentrations, routes, release properties, species labeling or regional availability.
Zenrelia
- Formulation
- Oral tablet
- Label / product scope
- Dogs
Ilunocitinib; current vaccine and infection precautions are essential.
Product label / source ↗References & review status
Clinical reference updated October 16, 2026. Independent veterinary or veterinary-pharmacy review not yet completed. Evidence gaps remain explicitly identified; this page does not claim equivalence to a comprehensive, professionally reviewed veterinary formulary.
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