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Ideal First-Line Treatment for Itch

Resting itch face just met its match. Numelvi™ (atinvicitinib tablets) is a second-generation Janus kinase (JAK) inhibitor¹ for the control of pruritus associated with allergic dermatitis in dogs 6 months of age and older. Numelvi relieves itch from allergic dermatitis while simplifying treatment for dogs, their owners, and veterinarians.

The first and only second-generation JAK inhibitor for dogs that is at least 10X more selective for JAK1¹*, the primary driver of itch and inflammation.²

Rapid relief starts within 2-4 hours.^3†

>82% of dogs showed significant^‡ improvement within 1 week.⁴

The only JAK inhibitor safe for use in dogs and puppies as young as 6 months of age and can be used in dogs weighing at least 2 kg.

Easy once-daily dosing from day 1.^§

* Over the other JAK enzymes in in vitro assays.
† In a canine interleukin-31 (cIL-31)-induced pruritus model.
‡ A ≥2 cm reduction in owner Pruritus Visual Analog Scale.
§ Numelvi is taken at or around mealtime.

The Science of Selectivity^™

Cytokines use JAK enzymes to stimulate immune cells.
JAK1 is the primary driver of itch and inflammation.²
First-generation JAK inhibitors target the JAKs with little to no selectivity.^5,6
High selectivity for JAK1 minimizes interference with the beneficial immune functions of the other JAKs.²

Numelvi is at least 10X more selective for JAK1¹* over the other JAKs.

Apoquel® (oclacitinib tablet) is only 1.8X more selective for JAK1 over JAK2.⁵

* Over the other JAK enzymes in in vitro assays.

Safety in Clinical Studies^7-9

Numelvi is proven safe—even in puppies as young as 6 months of age—with no serious treatment-related adverse reactions.

No evidence of:

Papillomas
Skin masses
Serious infections
Drug interactions^||

No interference with:

Red blood cell counts
Mean white blood cell counts
Serological response to vaccination

^|| No clinically relevant drug interactions observed during 28-day field trial in dogs with allergic dermatitis after use with antimicrobials (including topicals), ecto- and endoparasiticides (isoxazolines, milbemycins, avermectins, pyrethrins, and pyrethroids), analgesics, anesthetics, nutritional supplements, topical skin and ear cleansers that did not contain glucocorticoids, as well as medicated shampoos.

The future of itch relief offers patients proven safety with adequate serological response to vaccination.⁷

Hear From the Experts

Watch as veterinary professionals discuss the benefits of Numelvi.

Benefits of Selectivity

“Numelvi really has the opportunity to change the game.”

Watch to hear more from Dr Christine McKinney, DACVD, Veterinary Dermatologist, Merck Animal Health

Proven Efficacy

“Within hours of starting the meds, the dog stopped itching and had stopped itching for the first time in months.”

Watch to hear more from Dr Sam Geller, General Practitioner, USA

Simplicity and Convenience

“The response to the drug was excellent. I would use it on my own dog.”

Watch to hear more from Dr Bob Sarsfield, General Practitioner, USA

Compare Numelvi to the Competition

* Over the other JAK enzymes in in vitro assays.
^§ Numelvi is taken at or around mealtime.
^¶ Inactivated rabies, multivalent modified live canine distemper virus (CDV), modified live canine adenovirus type-2 (CAV2), and modified live canine parvovirus (CPV) vaccine.
^# Except for modified live (MLV) canine parainfluenza virus (CPI); MLV canine adenovirus-2 (CAV2) not analyzed.

Starts Reducing Itch Within 2-4 hours^3†

Once-daily dosing starts relieving itch from day 1 with continued improvement thereafter.⁷

>82% of dogs treated with Numelvi had significant^‡ improvement in itch within 1 week.⁴

† In a canine interleukin-31 (cIL-31)-induced pruritus model.
‡ A ≥2 cm reduction in owner Pruritus Visual Analog Scale.

Available in 4 Convenient Strengths

Most Dogs Require Just a Single Tablet or Half-Tablet Daily

Numelvi is administered orally, once daily, at or around mealtime at a dose of 0.8-1.2 mg/kg (0.36-0.54 mg/lb) body weight according to the dosing table below.^**

** For dogs ≥ 174.3 lb (≥79.1 kg), administer the appropriate combination of tablet strengths to achieve the target dose of 0.8-1.2 mg/kg.

Tablets not to scale.

Dosing Calculator

Determine the right dose instantly. Simply enter your patient’s weight to calculate.

LAUNCH CALCULATOR

Simplicity and Convenience

Numelvi makes managing itch seamless.

Simple for Veterinarians

Consistent dosing improves compliance
Safe
Unflavored tablets
Ready-to-dispense bottles

Simple for Pet Owners

1 dose per day from the start
Starts reducing itch within 2-4 hours^3†
Proven safety

† In a canine interleukin-31 (cIL-31)-induced pruritus model.

Resources

Access these materials for additional support prescribing Numelvi for your patients.

Numelvi Promise

Learn more about how we’re ensuring that Numelvi meets product expectations for both veterinarians and pet parents.

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Dosing Chart

Make quick, confident dosing decisions with our chart designed to simplify your day.

Download

Numelvi Itch Tracker

Utilize this itch tracker to track your dog’s progress and be sure to bring it with you to your veterinarian appointments.

Download

Pet Owner Handout

This one-page handout explains what to expect from treatment with Numelvi and offers tips on how to manage allergic dermatitis.

Download

Discover the revolutionary science behind Numelvi.

Learn more

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Important Safety Information

NUMELVI is not for use in dogs less than 6 months of age or those with serious infections. NUMELVI may increase susceptibility to opportunistic infections, including demodicosis and interdigital furunculosis. Consider the risks and benefits of treatment prior to initiating NUMELVI in dogs with a history of recurrent demodicosis. NUMELVI is a JAK inhibitor. New neoplastic conditions (benign and malignant) have been reported in dogs treated with other JAK inhibitors. The effectiveness and safety of NUMELVI have not been evaluated in a field study beyond 28 days. The safe use of NUMELVI has not been evaluated in breeding, pregnant, or lactating dogs, nor in combination with glucocorticoids, cyclosporine, or other systemic immunosuppressive agents. For complete safety information, refer to the product label.

See Full Prescribing Information

References

Kowalski T, Schuette S. The second-generation Janus kinase inhibitor atinvicitinib is a potent and highly selective inhibitor of JAK1. Vet Dermatol. 2026;0:17. https://doi.org/10.1111/vde.70046
Huang IH, Chung WH, Wu PC, Chen CB. JAK-STAT signaling pathway in the pathogenesis of atopic dermatitis: an updated review. Front Immunol. 2022;13:1068260. doi:10.3389/fimmu.2022.1068260
Kowalski T, Prohaczik A, Locke K, et al. The second-generation Janus kinase inhibitor atinvicitinib significantly reduces pruritus 2-4 hours after dosing dogs in a canine interleukin-31 model. Vet Dermatol. 2026;0:17-18. https://doi.org/10.1111/vde.70046
Data on File. Study Summary REF-12964. Merck Animal Health.
Gonzales AJ, Bowman JW, Fici GJ, Zhang M, Mann DW, Mitton-Fry M. Oclacitinib (APOQUEL®) is a novel Janus kinase inhibitor with activity against cytokines involved in allergy. J Vet Pharmacol Ther. 2014;37(4):317-324. doi:10.1111/jvp.12101
Zenrelia. Package insert. Elanco; 2025.
Numelvi. Product label. Merck Animal Health; 2025.
Freedom of Information Summary. NADA 141-596.
Data on File. Study Summary REF-11202. Merck Animal Health.
Apoquel. Package insert. Zoetis Inc.; 2020.
Forster S, Trout CM, Despa S, Boegel A, Berger D, King S. Efficacy and field safety of ilunocitinib for the control of allergic dermatitis in client-owned dogs: a multicenter, double-masked, randomised, placebo-controlled clinical trial. Vet Dermatol. 2025;36(6):825-837. doi:10.1111/vde.70009