ZenreliaTM — veterinary medication

Overview

Source: Animal Drugs @ FDA

Proprietary name

ZenreliaTM

Active ingredient

Ilunocitinib

Application type

NADA

Sponsor

Elanco US Inc.

Applications on record

1

First published

July 8, 2026

Adverse event reports

Source: openFDA VeDDRA

1,776

Reports mentioning this ingredient

May 6, 2022 – March 26, 2026

400

Classified serious

per reporter assessment

346

Lack of expected efficacy

resistance signal

6

Human operator exposure

needle-stick or splash

Not a risk measure. Veterinary adverse event reports are influenced by how many animals are treated, reporting practice and product age. Reports do not establish that the product caused the event, and a single report can cover an entire herd or flock. Attribution here is by active ingredient because the source dataset redacts brand names.

Attributed by active ingredient “ILUNOCITINIB”. Green Book ingredient names and VeDDRA ingredient names do not always agree exactly, so attribution is approximate and labelled as such.

Reported reactions

Source: openFDA VeDDRA

Clinical signs coded in the VICH VeDDRA four-level hierarchy, most frequent first.

Reaction terms reported for this ingredient, by report count.
Reaction (VeDDRA term)	Reports	Relative frequency
Lack of efficacy - NOS	262
Lethargy (see also Central nervous system depression in Neurological)	182
Diarrhoea	160
Vomiting	138
Neutropenia	138
Decreased haematocrit	100
Elevated serum alkaline phosphatase (ALP)	90
Leucopenia NOS	85
Lymphopenia	80
Elevated alanine aminotransferase (ALT)	76
Other abnormal test result NOS	72
Anaemia NOS	66
Decreased red blood cell count	66
Eosinopenia	59
Behavioural disorder NOS	57
Decreased haemoglobin	56
Leukopenia NOS	53
Death by euthanasia	49
Decreased appetite	48
Itching	45

Species affected

Source: openFDA VeDDRA

Dog 1,740 Human 4 Cat 1

Regulatory context

New Animal Drug Application (NADA). A pioneer approval evaluated for target animal safety, therapeutic effectiveness, manufacturing controls and — for food-producing species — human food safety including residue depletion.

Extra-label use in food-producing animals is governed by the Animal Medicinal Drug Use Clarification Act of 1994 (AMDUCA) and 21 CFR Part 530. It requires a valid veterinarian-client-patient relationship and is prohibited outright for certain drug classes. Withdrawal times are determined by FARAD, not by this index.

Sources for this page

Animal Drugs @ FDA	FDA CVM	Applications, sponsor, status, withdrawal
Animal & Veterinary Events	FDA CVM	VeDDRA adverse event aggregates by active ingredient