April 2001: adverse event reports received

1,272 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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1,272reports received

1,170same month a year earlier+9%

1,532monthly average, preceding 12 months

57.8%concern dogscats 13.9%

FDA's database holds 1,272 adverse event reports received in April 2001, against 1,170 in the same month a year earlier and a monthly average of 1,532 over the preceding 12 months.

57.8% of the month's reports concern dogs, 13.9% cats and 2% horses; the rest concern other species, exposed people, or give no species.

By active ingredient, the drugs named most often were selamectin (431), carprofen (253) and (s) - methoprene (60), and the terms listed most often were accidental exposure (238), no sign (182) and depression (136). 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
Selamectin	431	33.9%
Carprofen	253	19.9%
(S) - methoprene	60	4.7%
Doramectin	50	3.9%
Selegiline Hydrochloride	49	3.9%
Milbemycin Oxime	32	2.5%
Etodolac	29	2.3%
Enrofloxacin	28	2.2%
Lufenuron + Milbemycin Oxime	28	2.2%
Tilmicosin Phosphate	24	1.9%
Amoxicillin	18	1.4%
Melarsomine Dihydrochloride	18	1.4%
Moxidectin	14	1.1%
Albendazole	11	0.9%
Butorphanol Tartrate	11	0.9%

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

Accidental exposure[exposure that was not intended]18.7%238
No sign[no clinical sign was reported]14.3%182
Depression[dull, quiet or withdrawn]10.7%136
Vomiting10.2%130
Anorexia[not eating]7.4%94
Death6.8%87
Ineffective, heartworm larvae[legacy FDA term: the product did not have the expected effect (heartworm larvae)]6.4%82
Unclassifiable adverse event[event that fits no dictionary term]6.4%81
Diarrhoea[diarrhea]5.3%67
Ataxia[unsteady, uncoordinated movement]3.9%50
Death by euthanasia[the animal was euthanized]3.5%45
Elevated alanine aminotransferase (ALT)[a liver enzyme above the normal range]3.2%41
Lack of efficacy (ectoparasite) - flea[the product did not have the expected effect: fleas]3.2%41
Elevated serum alkaline phosphatase (SAP)[a liver and bone enzyme above the normal range]3.1%40
Application site alopecia[hair loss where the product was applied]2.9%37

Single ingredients, pooled

Selamectin33.9%431

Carprofen19.9%253

Milbemycin Oxime4.7%60

(S) - methoprene4.7%60

Doramectin3.9%50

Selegiline Hydrochloride3.9%49

Enrofloxacin3%38

Lufenuron2.7%34

Etodolac2.3%29

Tilmicosin Phosphate1.9%24

Amoxicillin1.4%18

Melarsomine Dihydrochloride1.4%18

Species

Dog57.8%735

Cat13.9%177

Horse2%25

Other or not given26.3%335

Questions about April 2001

How many animal drug adverse event reports did FDA receive in April 2001?

1,272 reports are in the openFDA release of 28 Sep 2026. The same month a year earlier has 1,170.

Which drugs were named most often?

By active ingredient: selamectin (431), carprofen (253), (s) - methoprene (60), doramectin (50) and selegiline hydrochloride (49). Brands are masked in the public data.

Which signs were listed most often?

accidental exposure (238), no sign (182), depression (136), vomiting (130) and anorexia (94).

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 30 Sep 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.