Fenbendazole: what the FDA reviewed for dog products
2 Freedom of Information summaries from the FDA Center for Veterinary Medicine for products containing Fenbendazole, as typed records: every value below is followed by the verbatim passage it was taken from. Species as stated by each summary: Dogs; Felidae and Ursidae.
Products
- Panacur® C (OTC) Safe-Guard® Canine (OTC) Panacur® Granules 22.2% (Rx) (NADA/ANADA 121-473)
Panacur® C (OTC) Safe-Guard® Canine (OTC) Panacur® Granules 22.2% (Rx) NADA 121-473, Supplemental approval, March 19, 2002; sponsor Intervet, Inc.; species: Dogs; foi_id 381; FDA PDF
Indication
Treatment and control of roundworms, hookworms, whipworms and tapeworms (Taenia pisiformis) in adult dogs (including pregnant bitches) and puppies six weeks of age or older.
Dose regimen
50 mg/kg (22.7 mg/lb) body weight daily, Oral, mixed with a small amount of the usual food, Once daily, Three (3) days in a row; packets of 1 g, 2 g and 4 g dosed by body weight
The daily dose for PANACUR®-C is 50 mg/kg (22.7 mg/lb.) of body weight.
Extraction notes: Supplemental approval (2002) changing the 22.2% granule packets from Rx to OTC status (PANACUR-C). The summary contains no studies: effectiveness and safety are stated to be unaffected and are cross-referenced to the original approval dated 27 October 1983. Agency conclusions note that the original Rx status reflected a hepatotoxicity concern and that post-approval marketing experience has not shown a pattern of liver disease. No PK, TAS or adverse-reaction data.
Panacur® C (OTC) Safe-Guard® Canine (OTC) Panacur® Granules 22.2% (Rx) NADA 121-473, Supplemental approval, May 31, 1994; sponsor Intervet, Inc.; species: Felidae and Ursidae; foi_id 1615; FDA PDF
Indication
Control of internal parasites (ascarids Toxocara cati/Toxascaris leonina, hookworms Ancylostoma spp., tapeworms Taenia spp. as listed per species) in wild Felidae (lion, tiger, cheetah, puma, panther, leopard, jaguar) and Ursidae (grizzly, polar and black bears).
Dose regimen
10 mg/kg/bw daily for 3 days, Orally, mixed with food or as a top dressing, Daily, 3 days
Felidae and Ursidae: 10 mg/kg/bw daily for 3 days
Target-animal safety
dose multiples 5X, 10X; duration Felidae dosed for six (6) days; polar bears for four (4) days.
Five big cats, including two jaguars, one puma, one lion, and one Siberian tiger representing both sexes and ranging in age from 2 to 15 years of age were dosed with the drug. Additionally, three polar bears ranging in age from 7 to 9 years of age and representing both sexes were dosed with 100 mg/kg/bw of the drug for four (4) days. The Felidae were dosed with 100 mg/kg/bw for six (6) days.
| Finding | Quote |
|---|---|
| Periods of inappetence in one jaguar and the lion after initial consumption at ten times the recommended level (extreme ambient heat noted as a possible factor) | In one jaguar and the lion, there were periods of inappentence (sic) following the initial consumption of fenbendazole at ten times the recommended level. |
| No adverse reactions at exaggerated doses; only remarkable finding was possible refusal of the drug | The only remarkable finding is that the overdosed animal may not consume the drug. |
| Safety parameters limited to clinical observation; no necropsies | Due to the nature of the study, safety parameters were limited to those which could be obtained from clinical observation of the animals. |
Effectiveness
Six pivotal zoo field trials (three in Felidae with 29 animals, three in Ursidae with 26 animals) using each animal as its own control by comparing pre- and post-treatment fecal ova counts; three corroborative trials; no statistics applied; primary endpoint: Reduction in fecal parasite ova counts post-treatment; result: 100% reduction in Ancylostoma and Taenia spp. ova where observed; 100% reduction in ascarid ova in most bear studies and 80% in one (bears dosed 2 days, hence 3-day label); pronounced pre/post difference in greater than 90% of animals tested
There are three studies involving 29 members of the family Felidae and three studies involving 26 members of the family Ursidae.
Adverse reactions
| Term | Treated | Control | Quote |
|---|---|---|---|
| Loose stools (pumas, field trial) | There were several reports of loose stools among the pumas ingesting the Panacur® granules. | ||
| Loose stools (bears, field trial) | There were several reports of loose stools among the bears ingesting the Panacur® granules. |
Extraction notes: Supplemental approval (1994) for zoo Felidae and Ursidae, NOT dogs (species_class recorded as stated). Subjects are lions, tigers, cheetahs, pumas, jaguars, leopards, panthers and bears, so n_dogs is null and animal counts are in the design field. Safety study: 5 big cats at 100 mg/kg for 6 days and 3 polar bears at 100 mg/kg for 4 days (10X the 10 mg/kg label dose); the summary also describes this as 'Large cats offered 5X the dose for twice the duration and polar bears dosed at 10X', so both multiples are listed. n_animals left null because 'Five' and 'three' appear as words, not digits, in the design quote. No PK data; adverse reactions have no counts.
Reproduce: foi_structured_search(query="Fenbendazole") and foi_summary_get(foi_id=...) in dog-geroscience-mcp; dataset foi-summaries-dog (config structured).