Breed · Dog

Pit Bull: adverse event reports

FDA breed label "Pit Bull" · single-breed animals only

Read this first · FDA's caveat, in its words

An API dataset query result cannot be used to estimate the risk associated with the product or compare one drug or device product with another. When looking at the results, be aware that there is no certainty that the reported drug or device caused the adverse event. This dataset should not be the sole source of information for clinical decision-making or other assumptions about the safety or effectiveness of a product. The adverse event may have been related to an underlying disease, other drugs used at the same time or other non-drug related sources. FDA Center for Veterinary Medicine

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Not veterinary advice. This site lists what was reported to FDA. For an animal that is unwell, contact a veterinarian.

14,236reports, 1987–20261.4% of dog reports

565reports, 12 months to March 2026564 in the 12 months before

33.2%classed serious, as reportedall dogs: 38.3%

18.9%name milbemycin oxime + spinosadall dogs: 13.1%

FDA's database holds 14,236 reports where the animal's breed is given as "Pit Bull", shown here as Pit Bull: 1.4% of reports about dogs. Reports on crossbred animals are left out of breed pages.

565 reports arrived in the 12 months to March 2026, close to the 564 of the 12 months before. A breed's count mostly mirrors how common the breed is; registration and ownership figures by breed are not public data, so no per-animal rate can be given.

By active ingredient, the drugs named most often are milbemycin oxime + spinosad, ivermectin + pyrantel pamoate and fluralaner. Milbemycin Oxime + Spinosad is named in 18.9% of this breed's reports, a larger share than in reports about all dogs (13.1%).

The terms listed most often are vomiting (20.7%), ineffective, heartworm larvae (9%) and lack of efficacy (endoparasite) - heartworm (8.9%). Vomiting appears in 20.7% of reports, about the same share as in all dog reports (19.7%). 33.2% of reports stating seriousness were classed as serious, against 38.3% for dogs overall.

Drugs named most often, by active ingredient

Active ingredients recorded for the drug	Reports	Share of Pit Bull reports	Share of all dog reports
Milbemycin Oxime + Spinosad	2,684	18.9%	13.1%
Ivermectin + Pyrantel Pamoate	2,383	16.7%	14.9%
Fluralaner	1,413	9.9%	6.7%
Spinosad	1,183	8.3%	5.8%
Afoxolaner	847	5.9%	5.7%
Milbemycin Oxime + Praziquantel	586	4.1%	3.1%
Melarsomine Dihydrochloride	552	3.9%	2.3%
Lufenuron + Milbemycin Oxime	398	2.8%	2.7%
Milbemycin Oxime	367	2.6%	3%
Imidacloprid + Moxidectin	321	2.3%	1.3%
Nitenpyram	321	2.3%	1.1%
Carprofen	303	2.1%	4.8%
Selamectin	227	1.6%	3%
Ivermectin	225	1.6%	1.3%
Tigilanol tiglate	214	1.5%	0.2%
Pyrantel Pamoate	207	1.5%	0.5%
Moxidectin	196	1.4%	5%
Praziquantel + Pyrantel Pamoate	195	1.4%	0.4%
Cyclosporine	174	1.2%	1.5%
Fenbendazole	170	1.2%	0.3%

Ordered by report count. Differences from the species column often come from body size (which drugs a breed is prescribed) and from how common the breed was in the years a drug sold most. FDA states that these data cannot be used to estimate risk or to compare one product with another. Brand and manufacturer names are masked by FDA in these records.

Signs listed in reports

share of Pit Bull reports listing the termall dog reports

Vomiting20.7%2,947
Ineffective, heartworm larvae[legacy FDA term: the product did not have the expected effect (heartworm larvae)]9%1,277
Lack of efficacy (endoparasite) - heartworm[the product did not have the expected effect: heartworm]8.9%1,274
Emesis[vomiting]8.7%1,234
Lethargy[unusually tired or inactive]7.6%1,077
Lack of efficacy (ectoparasite) - flea[the product did not have the expected effect: fleas]6.8%961
Diarrhoea[diarrhea]6.6%935
Anorexia[not eating]4.2%592
Lack of efficacy - NOS[the product did not have the expected effect]4.1%580
Lack of efficacy (endoparasite) - hookworm[the product did not have the expected effect: hookworms]3.3%467
Depression[dull, quiet or withdrawn]3.2%456
Death2.6%365
Ataxia[unsteady, uncoordinated movement]2.5%357
Emesis (multiple)[vomiting more than once]2.4%342
Pruritus[itching]2.1%294
Not eating1.9%268
Seizure NOS[seizure, type not specified]1.8%258
Hives1.8%257
Behavioural disorder NOS[behaviour change, type not specified]1.7%249
Cardiac disorder NOS[heart problem, type not specified]1.7%243
Overdose[more than the labelled amount was given]1.6%224
Weight loss1.6%222
Accidental exposure[exposure that was not intended]1.5%219
Digestive tract disorder NOS[digestive problem, type not specified]1.5%217
Ineffective, hooks[legacy FDA term: the product did not have the expected effect (hooks)]1.5%212

Age and weight

Age of the animal

Under 1 year17.4%2,480

1 to 3 years39.3%5,596

4 to 7 years24.7%3,517

8 to 11 years12.1%1,717

12 years and over3.7%529

Age not given2.8%397

Weight of the animal

Under 5 kg (11 lb)2.9%412

5 to 9.9 kg (11–22 lb)3.1%436

10 to 24.9 kg (22–55 lb)32.3%4,598

25 to 44.9 kg (55–99 lb)56.7%8,068

45 kg and over (99 lb+)1.7%249

Weight not given3.3%473

Coloured bar: Pit Bull reports. Grey bar: all dog reports.

Trend and outcomes

Reports by month FDA received them. The newest months are incomplete because FDA posts reports with a delay of three to six months.

Outcome recorded in the report

Recovered/Normal27.5%3,910

Recovered with Sequela4.7%671

Ongoing13.6%1,938

Died3.1%445

Euthanized1%138

Outcome Unknown31.3%4,449

Beside all dogs

Measure	Pit Bull	All dogs
Reports	14,236	985,675
Latest 12 months	565	53,292
Classed serious, of reports stating it	33.2%	38.3%
Death or euthanasia recorded, per 1,000 reports	40.9	55

Questions about Pit Bull reports

How many FDA adverse event reports involve Pit Bulls?

14,236 reports through March 2026, 1.4% of reports about dogs; 565 in the latest 12 months.

Which drugs are named most often in Pit Bull reports?

By active ingredient: milbemycin oxime + spinosad (2,684), ivermectin + pyrantel pamoate (2,383), fluralaner (1,413), spinosad (1,183) and afoxolaner (847). Brands are masked in the public data.

What signs are reported most for this breed?

vomiting (20.7%), ineffective, heartworm larvae (9%), lack of efficacy (endoparasite) - heartworm (8.9%), emesis (8.7%) and lethargy (7.6%).

Is the Pit Bull more sensitive to certain drugs?

Report counts cannot answer that. They show what was reported, not what a drug did, and they are not adjusted for how many Pit Bull animals exist or were treated. Breed-related drug sensitivities that are established are described on FDA-approved labels; a veterinarian is the person to ask about an individual animal.

Why are crossbreds not included?

FDA records crossbred animals with one or more component breeds. Counting them under each component would double count, so breed pages use single-breed reports only. Crossbreds remain in the species totals.

How do I report a problem?

Call the drug company using the number on the label, or send Form FDA 1932a to FDA. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Animal & Veterinary adverse event bulk files released 28 Sep 2026, which hold reports FDA's Center for Veterinary Medicine received through 31 Mar 2026. openFDA masks brand and manufacturer names in these files, so drugs are counted by the active ingredients each record discloses and no figure is attributed to a brand, application or company. Ingredient names, and the separate reference lists of approved products, follow the FDA Green Book as of 30 Sep 2026. Breed names are FDA's labels rearranged into everyday order ("Pit Bull" becomes "Pit Bull"). No report text, lot numbers or reporter details are published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.