How long does Simparica remain effective against ticks? - briefly
A single oral dose of Simparica protects dogs from tick infestations for up to 35 days (about one month). To maintain continuous protection, the medication should be given each month.
How long does Simparica remain effective against ticks? - in detail
Simparica, containing the active ingredient sarolaner, is administered orally as a chewable tablet. After a single dose, the product begins killing attached ticks within 8 hours and eliminates most infestations by 24 hours. The protective window extends for a full month, with efficacy demonstrated up to 35 days after treatment when administered at the label‑recommended dose of 2 mg per kilogram of body weight.
Key aspects of the duration of tick control:
- Onset of action: Killing of existing ticks starts within the first 8 hours; the majority are dead by 24 hours.
- Sustained protection: Laboratory and field trials show ≥90 % efficacy against Ixodes scapularis, Rhipicephalus sanguineus, Dermacentor variabilis, and Amblyomma americanum throughout the 35‑day interval.
- Dosage compliance: Maintaining the monthly dosing schedule is essential; missed doses shorten the protective period and may allow re‑infestation.
- Weight considerations: The label dose is calibrated for dogs ≥2 kg; under‑dosing in larger animals reduces the duration of effectiveness.
- Resistance factors: Current data indicate low resistance development, but regional variations in tick susceptibility can affect the exact length of protection.
The product’s label specifies that a new dose should be given every 30 days to ensure continuous coverage. Administering earlier than the 30‑day interval does not increase the protective period and may lead to unnecessary drug exposure. For dogs with heavy tick burdens or exposure to multiple species, veterinarians may recommend a concurrent environmental control program to complement the oral treatment.
In practice, owners who follow the monthly schedule can expect reliable tick control for the entire month, with the majority of ticks eliminated within the first day after each administration.