Your dogs and outside cats should use flea and tick protection because of the diseases these parasites carry.  In most cases those diseases are far worse than the flea and tick protection.

However, recent customer stories about sick dogs and puppies, and dogs having seizures led me to further investigate the ORAL flea and tick medication category.

Astoundingly, Simparica Trio, Bravecto and Nexguard are all approved while still causing a myriad of side effects.  Precaution statements indicate these medications may cause abnormal neurologic signs such as tremors, decreased conscious proprioception, ataxia, decreased or absent menace, and/or seizures.  The most serious side effects being neurological disorders and gastric bleeding that require the pet to be euthanized.  While the incidence of severe reaction/death is very low, there seems to be no predictive element that can screen out the pet likely to experience this.

Complicating the use of these medicines further, some reactions did not occur with the first dose, but presented only after as much as 3 months/ 3 doses.

The US field study on Simparica included 479 dogs (315 dogs received Simparica and 164 dogs received an active control once monthly for three months). The top adverse reactions were vomiting (0.95%), diarrhea (0.63%), and lethargy (0.32%).

The last paragraph of Simparica Trio insert states: “In a separate exploratory pharmacokinetic study, one female dog dosed at 12 mg/kg (3X the maximum recommended dose) exhibited lethargy, anorexia, and multiple neurological signs including ataxia, tremors, disorientation, hypersalivation, diminished proprioception, and absent menace, approximately 2 days after a third monthly dose. The dog was not treated, and was ultimately euthanized. The first two doses resulted in plasma concentrations that were consistent with those of the other dogs in the treatment group. Starting at 7 hours after the third dose, there was a rapid 2.5 fold increase in plasma concentrations within 41 hours, resulting in a Cmax more than 7-fold higher than the mean Cmax at the maximum recommended use dose. No cause for the sudden increase in sarolaner plasma concentrations was identified.“  

For the dogs that died from normal dosing, these were the very same symptoms and the industry has no explanation.

Buyer beware.

Sources: Zoetis Simparica insert; Elizabeth Carney, DVM (Holistic)

Photo credit: WebMD