Lack of efficacy (endoparasite) - Haemonchus

Lack of efficacy (endoparasite) - Haemonchus Reaction Insights

The FDA Center for Veterinary Medicine database currently lists 23 adverse event reports that reference Lack of efficacy (endoparasite) - Haemonchus as a reaction term, including 8 reports with a death outcome — a 3480.0% case-fatality figure calculated across only those events where this reaction was coded. The reaction is indexed in the openFDA system under VeDDRA code 2797, the standardized veterinary dictionary used to normalize clinical signs across submitters. Because reports are voluntary and often describe multiple concurrent signs per animal, the volume here reflects reporting intensity rather than true incidence in the broader pet population.

Lack of efficacy (endoparasite) - Haemonchus appears most frequently in reports for Cattle (16 reports), Sheep (5 reports), Cat (1 reports) — with Cattle dominating at 16 entries. Within those species, the breeds most often named alongside this reaction are Aberdeen Angus (6), Cattle (other) (5), Sheep (unknown) (3). These distributions are influenced both by underlying breed popularity and by how veterinarians and owners code a given clinical sign, so they should be interpreted as a reporting fingerprint rather than a pure susceptibility ranking.

The drugs most commonly co-reported with Lack of efficacy (endoparasite) - Haemonchus are Eprinomectin (12 reports), Moxidectin (3 reports), Albendazole (3 reports), Oxfendazole (2 reports), with Eprinomectin appearing alongside this reaction in 12 submissions. Co-reporting does not establish that any specific product caused the reaction — FDA CVM data captures temporal association only. The value of these aggregates is in flagging which therapeutic classes appear repeatedly alongside a given clinical sign, so owners and veterinarians can ask targeted questions about medications currently in use.