Drug profile

The FDA adverse-event record for Frontline

34 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Frontline. See the species affected, top reactions, and outcomes below.

34
adverse-event reports
2.9%
death-coded share
Dog
most-reported species
8
Lack of efficacy (bacteria) - Borrelia - top reaction
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Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
34
Total Reports
1
Deaths Reported
2.9%
Death Rate

Active Ingredients

Frontline

Administration Routes

TopicalUnknown

Species Affected

Dog 27
Cat 7

Most Affected Breeds

Retriever - Labrador 6
Domestic Shorthair 4
Domestic Longhair 2
Crossbred Canine/dog 2
Siberian Husky 2
Doberman Pinscher 2
Terrier (unspecified) 2
Spaniel - Cocker American 1
Chihuahua 1
Spitz - American Eskimo Dog 1

Most Reported Reactions

Lack of efficacy (bacteria) - Borrelia 8
Lack of efficacy (bacteria) - NOS 4
Vomiting 3
Lethargy (see also Central nervous system depression in 'Neurological') 3
Lethargy (see also Central nervous system depression in Neurological) 3
Diarrhoea 2
Anorexia 2
Weight loss 2
Hot spot (pyotraumatic dermatitis) 2
Lack of efficacy (ectoparasite) - tick NOS 2
Application site alopecia 1
Anaemia NOS 1

Outcome Breakdown

Ongoing
21 (61.8%)
Outcome Unknown
8 (23.5%)
Recovered with Sequela
2 (5.9%)
Recovered/Normal
2 (5.9%)
Euthanized
1 (2.9%)

Frontline Adverse Event Insights

34 reports name Frontline; 1 recorded a death outcome (2.9% of reported events, not a population-level mortality rate). Active ingredient: Frontline. Administration routes: Topical, Unknown.

By species: Dog (27 reports), Cat (7 reports). By breed: Retriever - Labrador (6), Domestic Shorthair (4), Domestic Longhair (2).

Leading clinical signs: Lack of efficacy (bacteria) - Borrelia (8), Lack of efficacy (bacteria) - NOS (4), Vomiting (3), Lethargy (see also Central nervous system depression in 'Neurological') (3). Outcome, 34 coded reports: Ongoing leads at 61.8%.

Read these counts as reporting volume, not risk: per our methodology, a widely-prescribed drug will rack up more raw FDA reports in a given year than a rarely-used one at an identical true rate, so we recommend comparing within similar-exposure products rather than across the full 2025 catalog.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

Every figure on PlainBreed is rendered directly from FDA openFDA adverse event data, no number is typed in by an editor. This page draws directly on FDA openFDA data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.