How does Simparica work in dogs against ticks? - briefly
Simparica delivers sarolaner orally, which blocks GABA‑ and glutamate‑gated chloride channels in tick neurons, leading to paralysis and death. The drug is absorbed into the bloodstream, killing attached ticks within hours and maintaining efficacy for about a month.
How does Simparica work in dogs against ticks? - in detail
Simparica contains the isoxazoline compound sarolaner, a systemic ectoparasiticide formulated for oral administration to dogs. After ingestion, the drug is rapidly absorbed from the gastrointestinal tract, reaching peak plasma concentrations within 2–4 hours. It distributes throughout body tissues and persists in the bloodstream for at least 35 days, providing continuous protection against arthropod infestations.
The active molecule interferes with the function of γ‑aminobutyric acid (GABA)‑gated chloride channels in the nervous system of ticks. By blocking these inhibitory receptors, sarolaner induces uncontrolled neuronal firing, leading to hyperexcitation, loss of motor coordination, and eventual death of the parasite. This mode of action is selective for arthropods, because mammalian GABA receptors differ structurally, minimizing adverse effects on the host.
Efficacy has been demonstrated against a broad spectrum of tick species, including Rhipicephalus sanguineus, Dermacentor variabilis, Ixodes ricinus, and Amblyomma americanum. Studies show that 90 % of attached ticks are eliminated within 8 hours of treatment, and complete eradication occurs by 24 hours. The systemic nature of the product means that ticks are killed after they feed and ingest the drug, preventing transmission of tick‑borne pathogens such as Ehrlichia spp. and Babesia spp.
Recommended dosage is 2 mg/kg body weight, administered once monthly. The tablet should be given with food to enhance absorption. Safety data indicate a high margin of tolerance; common adverse events are mild gastrointestinal upset or transient lethargy. Contra‑indications include dogs younger than 8 weeks or weighing less than 2.0 kg, and animals receiving concomitant products containing other isoxazolines.
Resistance monitoring remains essential. While current field data show no widespread sarolaner resistance, repeated exposure may select for tolerant tick populations. Rotating ectoparasiticides with different mechanisms, when appropriate, helps preserve efficacy.