Topically administered macrocyclic lactone products, including eprinomectin, demonstrate comparable neurological...

The purpose of the study was to evaluate the proportional reporting of neurological adverse events (AEs) associated with feline topical parasiticide products containing macrocyclic lactones (MLs; including eprinomectin) and emodepside by use of postapproval pharmacovigilance data. The intent was to provide veterinarians prescribing these products for their feline patients with the overall comparative context of neurological AE reporting for these products, which have been characterized as substrates for P-glycoprotein transporters.

The openFDA and EudraVigilance Veterinary Data Warehouse databases were queried for neurological AEs cumulatively reported through December 31, 2024, for marketed parasiticide products containing MLs (eprinomectin, selamectin, moxidectin) and emodepside for topical administration to cats. The frequencies of neurological AE reporting were compared between products with proportional report rates and disproportionality statistical measures.

The reporting frequencies of neurological AEs associated with these feline topical parasiticide products were similar. For all products, ataxia was the most frequently reported neurological AE, with proportional report rates ranging from 5.3% to 14.0%. Proportional report rates ranged from 1.7% to 10.7% for convulsion and muscle tremor.

An evaluation of pharmacovigilance data from 2 different sources revealed no evidence of greater proportional reporting for neurological AEs specific to the use of eprinomectin-containing products in cats than for other MLs or emodepside.

These findings supported the conclusion that ML-containing products (including eprinomectin-containing products) and emodepside are comparable in the frequencies and types of neurological AEs associated with feline topical parasiticide products described as substrates for P-glycoprotein transporters.