December 2021: adverse event reports that FDA received

Month in which FDA received the reports

Read this first. FDA says this about the data:

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 publishes these words. Source: Adverse Event Reports for Animal Drugs and Devices, read on 2 Oct 2026. The data have the reports that FDA received through 26 Jun 2026.

FDA received 3,657 adverse event reports for animal drugs in December 2021. It received 4,308 reports in December 2020. The average of the 12 months before December 2021 is 5,318 reports for each month.

Of the 3,657 reports, 73.8% are about dogs, 10.5% are about cats and 1.1% are about horses. The other reports are about other species, or give no species. A report is not proof that a drug caused a sign.

Search engines do not list month pages. The site keeps the page, and the list of months links it.

The months before and after

Reports for each month, Jun 2020 to Jun 2022. The column with the outline is December 2021.

Reports by species

Dog73.8%2,699
Cat10.5%384
Horse1.1%39
Other species, or species not given14.6%535

Drug pages with reports received in December 2021

The table has every drug page with 10 or more reports that FDA received in December 2021, in order of name. No count decides which drug is in the table. The table has 64 drug pages.

Show the 64 drug pages

Drug pages with 10 or more reports received in December 2021, in order of name
Active ingredients	Reports received in December 2021
Afoxolaner	186
Amoxicillin Trihydrate + Clavulanate Potassium	13
Butorphanol Tartrate	16
Capromorelin	20
Carprofen	72
Cefovecin sodium	45
Cefpodoxime proxetil	10
Clotrimazole + Gentamicin	10
Cyclosporine	32
Deracoxib	12
Dexamethasone	14
Diphenhydramine	20
Doxycycline	21
Emodepside + Praziquantel	31
Enrofloxacin	16
Famotidine	13
Febantel + Praziquantel + Pyrantel Pamoate	41
Firocoxib	11
Florfenicol + Mometasone furoate + Terbinafine	25
Fluoxetine hydrochloride	13
Fluralaner	248
Fluralaner + Moxidectin	22
Gabapentin	31
Grapiprant	42
Imidacloprid	63
Imidacloprid + Moxidectin	31
Insulin	43
Ivermectin	25
Ivermectin + Pyrantel Pamoate	552
Ketamine Hydrochloride	11
Ketoconazole	14
Lotilaner	55
Lufenuron + Milbemycin Oxime	55
Lufenuron + Milbemycin Oxime + Praziquantel	34
Maropitant	59
Melarsomine Dihydrochloride	66
Meloxicam	22
Methylprednisolone Acetate	14
Metronidazole	11
Milbemycin Oxime	31
Milbemycin Oxime + Praziquantel	196
Milbemycin Oxime + Spinosad	148
Mirtazapine	19
Monensin	11
Moxidectin	305
Nitenpyram	65
Oclacitinib	73
Phenylpropanolamine hydrochloride	12
Pimobendan	23
Polysulfated Glycosaminoglycan	24
Praziquantel	12
Praziquantel + Pyrantel Pamoate	18
Prednisolone	12
Prednisone	40
Propofol	13
Pyrantel Pamoate + Sarolaner	452
Sarolaner	69
Sarolaner + Selamectin	111
Selamectin	58
Sodium Chloride	70
Spinosad	13
Tigilanol tiglate	38
Trazodone	10
Trilostane	69

The openFDA records give the value "MSK" for the brand name and for the manufacturer name of each drug. FDA says that MSK means "masked". So the site cannot count a report for a brand.

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.
Commonly used products may have a higher number of reported adverse events due to the higher total number of animals being given the product.
FDA Center for Veterinary Medicine. Source: Adverse Event Reports for Animal Drugs and Devices

Signs that the reports of the month list

A sign is a coded term from the report. The words in brackets are a plain gloss of the term. The percentage is the share of the 3,657 reports of the month.

The sign that is in the largest number of the reports comes first.

Lack of efficacy (endoparasite) - heartworm[the product did not have the expected effect: heartworm]14.6%535 reports
Vomiting13.2%482 reports
Lethargy[unusually tired or inactive]7%257 reports
Lack of efficacy (endoparasite) - hookworm[the product did not have the expected effect: hookworms]6.3%232 reports
Diarrhoea[diarrhea]5.3%193 reports
Lack of efficacy (ectoparasite) - flea[the product did not have the expected effect: fleas]4.9%178 reports
Lack of efficacy (ectoparasite) - tick NOS[the product did not have the expected effect: ticks]4.5%165 reports
Lack of efficacy (endoparasite) - roundworm NOS[the product did not have the expected effect: roundworms]3.8%138 reports
Seizure NOS[seizure, type not specified]3.5%129 reports
Death3.1%112 reports
Containers, Damaged[a product quality report, not a sign in an animal]2.9%106 reports
Lack of efficacy (bacteria) - Borrelia[the product did not have the expected effect: Borrelia (Lyme disease bacteria)]2.6%95 reports
Lack of efficacy - NOS[the product did not have the expected effect]2.6%95 reports
Emesis (multiple)[vomiting more than once]2.4%86 reports

Show the next 1 signs

Anorexia[not eating]2.1%78 reports

Ingredients, all combinations

The list has every active ingredient with 10 or more reports received in December 2021, in order of name. It has 64 ingredients.

Show the 64 ingredients

The same month in other years

Cite this page

Pet Drug Reports. December 2021: adverse event reports for animal drugs. https://petdrugreports.com/month/2021-12/ Source: FDA Center for Veterinary Medicine, openFDA Animal and Veterinary adverse event reports, export of 30 Oct 2026. Reports received through 26 Jun 2026.

Where the data come from

The counts come from the openFDA Animal and Veterinary adverse event files, export of 30 Oct 2026. The files have the reports that the FDA Center for Veterinary Medicine received through 26 Jun 2026. The files mask brand and manufacturer names. The site counts a drug by the active ingredients that each record gives, and gives no count to a brand, an application or a company. Ingredient names and the lists of approved products follow the FDA Green Book of 2 Nov 2026. The month is the month in which FDA received the report, not the month of the event.

The site does not publish report text, lot numbers or details of a reporter. FDA's record is the authority. See how the site counts reports, the data sources and the corrections page.

Questions about this month

Can the count for December 2021 change?: Yes. FDA says that a report can take 3 to 6 months to reach the public data. The newest months can get more reports in a later update.
Does the month show when the event occurred?: No. The month is the month in which FDA received the report. The event can be from an earlier month.
Which sign is in the largest number of the reports of the month?: "Lack of efficacy (endoparasite) - heartworm" is in 535 reports of the 3,657 reports of December 2021 (14.6%).