Loncor® 300 — veterinary medication

Overview

Source: Animal Drugs @ FDA

Proprietary name

Loncor® 300

Active ingredient

Florfenicol

Application type

ANADA

Sponsor

Zoetis Inc.

Applications on record

1

First published

December 22, 2025

Adverse event reports

Source: openFDA VeDDRA

6,897

Reports mentioning this ingredient

January 7, 1996 – March 25, 2026

2,430

Classified serious

per reporter assessment

2,143

Lack of expected efficacy

resistance signal

176

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 “FLORFENICOL”. 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	1,689
Ataxia	576
Head tilt - ear disorder	435
Vomiting	410
Ear discharge	358
Head shake - ear disorder	318
Nystagmus	311
Behavioural disorder NOS	281
Unclassifiable adverse event	278
Lethargy (see also Central nervous system depression in 'Neurological')	276
Anorexia	272
Vestibular disorder NOS	262
Corneal ulcer	260
Death	252
Deafness	243
Underfilling, Package	225
Not eating	210
Horner's syndrome	204
Lack of efficacy (bacteria) - NOS	202
Loss of hearing	200

Species affected

Source: openFDA VeDDRA

Dog 4,540 Cat 672 Cattle 347 Human 270 Fish 47 Pig 32 Goat 16 Sheep 10 Horse 9 Other 5 Guinea Pig 1 Donkey 1

Regulatory context

Abbreviated New Animal Drug Application (ANADA). A generic animal drug demonstrating bioequivalence, pharmaceutical equivalence and identical manufacturing criteria to the pioneer application. Veterinary generics have no formal therapeutic-equivalence coding system; they match the pioneer NADA specification instead.

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