Breed · Dog

West Highland White Terrier: adverse event reports

FDA breed label "Terrier - West Highland White" · 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

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated. We may limit or otherwise restrict your access to the API in line with our Terms of Service.

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

5,606reports, 1987–20260.6% of dog reports

163reports, 12 months to March 2026157 in the 12 months before

39.1%classed serious, as reportedall dogs: 38.3%

14.1%name cyclosporineall dogs: 1.5%

FDA's database holds 5,606 reports where the animal's breed is given as "Terrier - West Highland White", shown here as West Highland White Terrier: 0.6% of reports about dogs. Reports on crossbred animals are left out of breed pages.

163 reports arrived in the 12 months to March 2026, close to the 157 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 cyclosporine, milbemycin oxime + spinosad and ivermectin + pyrantel pamoate. Cyclosporine is named in 14.1% of this breed's reports, a larger share than in reports about all dogs (1.5%).

The terms listed most often are vomiting (25.8%), diarrhoea (9.8%) and emesis (8.8%). Vomiting appears in 25.8% of reports, a larger share than in all dog reports (19.7%). 39.1% 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 West Highland White Terrier reports	Share of all dog reports
Cyclosporine	793	14.1%	1.5%
Milbemycin Oxime + Spinosad	778	13.9%	13.1%
Ivermectin + Pyrantel Pamoate	534	9.5%	14.9%
Oclacitinib	400	7.1%	2.9%
Spinosad	357	6.4%	5.8%
Fluralaner	250	4.5%	6.7%
Afoxolaner	231	4.1%	5.7%
Carprofen	179	3.2%	4.8%
Moxidectin	168	3%	5%
Lufenuron + Milbemycin Oxime	161	2.9%	2.7%
Selamectin	157	2.8%	3%
Pyrantel Pamoate + Sarolaner	143	2.6%	5.1%
Milbemycin Oxime	125	2.2%	3%
Insulin	124	2.2%	0.7%
Prednisone	95	1.7%	0.9%
Ivermectin	86	1.5%	1.3%
Milbemycin Oxime + Praziquantel	84	1.5%	3.1%
Maropitant	83	1.5%	1.2%
Trilostane	75	1.3%	1.2%
Sarolaner	71	1.3%	1.7%

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 West Highland White Terrier reports listing the termall dog reports

Vomiting25.8%1,444
Diarrhoea[diarrhea]9.8%549
Emesis[vomiting]8.8%491
Lethargy[unusually tired or inactive]8.3%464
Anorexia[not eating]6.5%364
Depression[dull, quiet or withdrawn]4.9%276
Lack of efficacy - NOS[the product did not have the expected effect]4.7%263
Lack of efficacy (ectoparasite) - flea[the product did not have the expected effect: fleas]4%226
Elevated serum alkaline phosphatase (SAP)[a liver and bone enzyme above the normal range]3.6%204
Deafness3.6%201
Polydipsia[drinking more than usual]3.4%188
Death by euthanasia[the animal was euthanized]3.2%179
Lack of efficacy (endoparasite) - hookworm[the product did not have the expected effect: hookworms]3.2%177
Other abnormal test result NOS[abnormal laboratory result, type not specified]2.9%160
Polyuria[passing more urine than usual]2.8%159
Pruritus[itching]2.8%159
Elevated alanine aminotransferase (ALT)[a liver enzyme above the normal range]2.6%148
Ineffective, heartworm larvae[legacy FDA term: the product did not have the expected effect (heartworm larvae)]2.4%135
Weight loss2.3%130
Death2.3%129
Behavioural disorder NOS[behaviour change, type not specified]2.2%121
Ataxia[unsteady, uncoordinated movement]2.1%117
Trembling2%111
Gingival hyperplasia2%110
Shaking1.9%109

Age and weight

Age of the animal

Under 1 year5.9%329

1 to 3 years19.2%1,079

4 to 7 years25.5%1,427

8 to 11 years25.5%1,432

12 years and over20.9%1,169

Age not given3%170

Weight of the animal

Under 5 kg (11 lb)3.7%205

5 to 9.9 kg (11–22 lb)72.5%4,067

10 to 24.9 kg (22–55 lb)19.2%1,075

25 to 44.9 kg (55–99 lb)0%0

45 kg and over (99 lb+)0%0

Weight not given4.6%259

Coloured bar: West Highland White Terrier 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/Normal26.7%1,499

Recovered with Sequela3.1%175

Ongoing16.1%901

Died3.8%214

Euthanized1.9%109

Outcome Unknown17.1%961

Beside all dogs

Measure	West Highland White Terrier	All dogs
Reports	5,606	985,675
Latest 12 months	163	53,292
Classed serious, of reports stating it	39.1%	38.3%
Death or euthanasia recorded, per 1,000 reports	57.6	55

Questions about West Highland White Terrier reports

How many FDA adverse event reports involve West Highland White Terriers?

5,606 reports through March 2026, 0.6% of reports about dogs; 163 in the latest 12 months.

Which drugs are named most often in West Highland White Terrier reports?

By active ingredient: cyclosporine (793), milbemycin oxime + spinosad (778), ivermectin + pyrantel pamoate (534), oclacitinib (400) and spinosad (357). Brands are masked in the public data.

What signs are reported most for this breed?

vomiting (25.8%), diarrhoea (9.8%), emesis (8.8%), lethargy (8.3%) and anorexia (6.5%).

Is the West Highland White Terrier 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 West Highland White Terrier 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 1 Oct 2026. Breed names are FDA's labels rearranged into everyday order ("Terrier - West Highland White" becomes "West Highland White Terrier"). 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.