December 2023: adverse event reports received

4,825 reports in the openFDA release of 28 Sep 2026

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.

4,825reports received

3,925same month a year earlier+23%

5,373monthly average, preceding 12 months

68.7%concern dogscats 18.4%

FDA's database holds 4,825 adverse event reports received in December 2023, against 3,925 in the same month a year earlier and a monthly average of 5,373 over the preceding 12 months.

68.7% of the month's reports concern dogs, 18.4% cats and 0.9% horses; the rest concern other species, exposed people, or give no species.

By active ingredient, the drugs named most often were pyrantel pamoate + sarolaner (656), bedinvetmab (597) and ivermectin + pyrantel pamoate (362), and the terms listed most often were vomiting (541), lack of efficacy (endoparasite) - heartworm (415) and lethargy (402). Report volume has a seasonal shape, with more reports in the warmer months when parasite products are in heavier use.

The months around it

Drugs named most often, by active ingredient

Active ingredients recorded for the drug	Reports	Share of the month's reports
Pyrantel Pamoate + Sarolaner	656	13.6%
Bedinvetmab	597	12.4%
Ivermectin + Pyrantel Pamoate	362	7.5%
Fluralaner	262	5.4%
Moxidectin	251	5.2%
Afoxolaner	221	4.6%
Frunevetmab	195	4%
Milbemycin Oxime + Praziquantel	188	3.9%
Gabapentin	162	3.4%
Oclacitinib	158	3.3%
Carprofen	149	3.1%
Bexagliflozin	132	2.7%
Maropitant	114	2.4%
Afoxolaner + Moxidectin + Pyrantel Pamoate	109	2.3%
Buprenorphine	106	2.2%

Ordered by report count, which follows how widely each drug was in use. 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 most often

Vomiting11.2%541
Lack of efficacy (endoparasite) - heartworm[the product did not have the expected effect: heartworm]8.6%415
Lethargy[unusually tired or inactive]8.3%402
Lack of efficacy - NOS[the product did not have the expected effect]6.1%296
Diarrhoea[diarrhea]5.8%280
Lack of efficacy (bacteria) - Borrelia[the product did not have the expected effect: Borrelia (Lyme disease bacteria)]3.9%187
Seizure NOS[seizure, type not specified]3.8%185
Death3.8%182
Not eating3.6%175
Lack of efficacy (endoparasite) - roundworm NOS[the product did not have the expected effect: roundworms]3.3%161
Lack of efficacy (ectoparasite) - flea[the product did not have the expected effect: fleas]3.3%157
Death by euthanasia[the animal was euthanized]3.1%148
Lack of efficacy (endoparasite) - hookworm[the product did not have the expected effect: hookworms]3%147
Weight loss2.6%125
Lack of efficacy (endoparasite) - tapeworm[the product did not have the expected effect: tapeworms]2.4%114

Single ingredients, pooled

Pyrantel Pamoate24.9%1,201

Sarolaner16.5%797

Bedinvetmab12.4%597

Moxidectin9.3%449

Praziquantel8.3%402

Ivermectin8.2%398

Milbemycin Oxime7.5%363

Afoxolaner6.8%328

Fluralaner6.1%292

Frunevetmab4%195

Gabapentin3.4%162

Oclacitinib3.3%158

Species

Dog68.7%3,314

Cat18.4%886

Horse0.9%45

Other or not given12%580

Questions about December 2023

How many animal drug adverse event reports did FDA receive in December 2023?

4,825 reports are in the openFDA release of 28 Sep 2026. The same month a year earlier has 3,925.

Which drugs were named most often?

By active ingredient: pyrantel pamoate + sarolaner (656), bedinvetmab (597), ivermectin + pyrantel pamoate (362), fluralaner (262) and moxidectin (251). Brands are masked in the public data.

Which signs were listed most often?

vomiting (541), lack of efficacy (endoparasite) - heartworm (415), lethargy (402), lack of efficacy - NOS (296) and diarrhoea (280).

Can the count for a month still change?

Yes. FDA posts reports quarterly with a delay of three to six months, so the newest months are incomplete and usually grow in later releases. Older months change little.

Does a busy month mean something went wrong that month?

Not by itself. The date is when FDA received the report, not when the event happened, and volume follows season, product launches and publicity. FDA states that "there is no certainty that the reported drug or device caused the adverse event" and that the event "may have been related to an underlying disease, other drugs used at the same time or other non-drug related sources."

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. The month is the date FDA first received the report, not the date of the event. 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.