How does Simparica work after a tick bite? - briefly
Simparica’s active ingredient, sarolaner, is absorbed into the bloodstream and eliminates attached ticks by interfering with their GABA‑gated chloride channels, halting feeding and reducing disease risk. A single dose provides continuous protection for up to 35 days.
How does Simparica work after a tick bite? - in detail
Simparica contains the active compound sarolaner, a member of the isoxazoline class. After oral administration, the drug is rapidly absorbed from the gastrointestinal tract, reaching peak plasma concentrations within 2–4 hours. Systemic circulation distributes sarolaner to all tissues, including the skin where attached ticks feed.
Sarolaner exerts its effect by binding selectively to ligand‑gated chloride channels that are regulated by γ‑aminobutyric acid (GABA) and glutamate in arthropod nervous systems. This binding blocks inhibitory neurotransmission, causing uncontrolled neuronal firing, paralysis, and death of the tick. Because the compound acts on internal receptors, it does not require direct contact with the parasite; the tick ingests the drug while feeding on the host’s blood.
Key pharmacological features that influence efficacy after a tick bite:
- Rapid onset: lethal concentrations are achieved within a few hours of ingestion, resulting in tick mortality typically within 8 hours of attachment.
- Sustained activity: the elimination half‑life of sarolaner is approximately 12 days, maintaining therapeutic plasma levels for a full month of protection.
- Broad spectrum: effective against multiple tick species, including Ixodes scapularis and Dermacentor variabilis, which are common vectors of bacterial pathogens.
- Prevention of pathogen transmission: most tick‑borne pathogens require several hours of feeding before transmission; the quick kill time reduces the window for disease transfer.
The systemic nature of Simparica also means that newly attached ticks encounter the drug shortly after beginning to feed, limiting their ability to establish a prolonged attachment. Consequently, the medication provides both therapeutic action against existing infestations and prophylactic protection against future bites.