Ilunocitinib

Indications

Zenrelia is indicated for control of pruritus associated with allergic dermatitis and control of atopic dermatitis in dogs at least 12 months of age.

Dosage and Administration

The dose of Zenrelia (ilunocitinib tablets) is 0.27 to 0.36 mg ilunocitinib/lb (0.6 to 0.8 mg ilunocitinib/kg) body weight, administered orally, once daily, with or without food. Dosing Chart Weight Range (in lb) Weight Range (in kg) Number of Tablets to be Administered 4.8 mg tablets 6.4 mg tablets 8.5 mg tablets 15 mg tablets 6.6 – 8.8 3.0 - 4.0 0.5 8.9 – 11.8 4.1 – 5.3 0.5 11.9 – 14.3 5.4 – 6.5 0.5 14.4 – 17.7 6.6 – 8.0 1 17.8 – 23.6 8.1 – 10.6 1 23.7 – 31.1 10.7 – 14.1 1 31.2 – 35.4 14.2 – 16.0 1.5 35.5 – 43.1 16.1 – 19.5 1.5 43.2 – 55.0 19.6 – 24.9 1 55.1 – 62.5 25.0 – 28.3 2 62.6 – 83.3 28.4 – 37.4 1.5 83.4 – 110.0 37.5 – 49.9 2 110.1 – 137.5 50.0 – 62.4 2.5 137.6 – 166.0 62.5 – 74.9 3 ≥ 166.1 ≥ 75 Administer the appropriate combination of tablet strengths

Warnings

User Safety Warnings Not for use in humans. Keep this drug out of the reach of children. Wash hands immediately after handling tablets. In case of accidental ingestion, seek medical attention immediately. Animal Safety Warnings Due to the risk of infections, dogs should be up to date on vaccinations prior to starting Zenrelia (see Target Animal Safety ). Due to the risk of an inadequate immune response to vaccines, do not administer vaccines to a dog receiving Zenrelia. Discontinue Zenrelia for at least 28 days to 3 months prior to vaccination and withhold Zenrelia for at least 28 days after vaccination (see Target Animal Safety ). Dogs should be monitored for the development of infections because Zenrelia may increase susceptibility to infections, including adenoviral hepatitis and pancreatitis, demodicosis, interdigital furunculosis, coccidiosis, and pneumonia, and exacerbation of subclinical or uncomplicated infections (see Target Animal Safety and Adverse Reactions ). Zenrelia is not for use in dogs with serious infections. Zenrelia may cause a progressive or persistently decreased hematocrit, hemoglobin, and/or red blood cell count without a corresponding increase in absolute reticulocyte count (see Target Animal Safety ). New neoplastic conditions (benign and malignant) were observed in dogs treated with Zenrelia during clinical studies (see

Precautions

The safe use of Zenrelia has not been evaluated in breeding, pregnant, or lactating dogs. Decreased prostate gland weights in intact male dogs were observed in a laboratory safety study (see Target Animal Safety ). The safe use of Zenrelia has not been evaluated in combination with glucocorticoids, cyclosporine, or other systemic immunosuppressive agents.

Adverse Reactions

). Consider the risks and benefits of treatment prior to initiating Zenrelia in dogs with a history of recurrent serious infections or recurrent demodicosis or neoplasia (see Adverse Reactions and Target Animal Safety ). Zenrelia modulates the immune system. Zenrelia is not for use in dogs less than 12 months of age (see Target Animal Safety ). Keep Zenrelia in a secure location out of reach of dogs, cats, and other animals to prevent accidental ingestion or overdose.

Description

Zenrelia is a synthetic Janus kinase (JAK) inhibitor. Zenrelia is a member of the pyrimidines class of JAK inhibitors and its chemical name is 2-[1-cyclopropylsulfonyl-3-[4-(7H-pyrrolo[2,3-d] pyrimidin-4-yl)pyrazol-1-yl]azetidin-3-yl]acetonitrile.

Storage

Store at room temperature between 15 to 25°C (59 to 77°F), excursions permitted between 5 to 40°C (41 to 104°F).

FDA adverse event reports

The FDA Center for Veterinary Medicine publishes the adverse event reports it receives through openFDA. The counts below are the reports naming ilunocitinib as an active ingredient for each species this label names, as returned on 2026-09-16, coded by the VeDDRA reaction term the reporter chose. Reactions are counted per report, so one report can appear under several terms.

These are counts, not rates. Reporting is voluntary, the number of animals treated is not known, and a widely used product accumulates reports for that reason alone. A report records that an event followed a dose; it does not establish that the product caused it. The counts say nothing about how one product compares with another.