Vetdrugs 2.0(S)-Methoprene is an insect growth regulator that interrupts flea development. It is used in environmental treatments and in topical combinations with adulticides. Its contribution is suppression of immature stages and subsequent adult emergence, supporting longer-term control of household flea populations and reinfestation.
Group
Insect growth regulator
Mechanism of Action
(S)-Methoprene mimics insect juvenile hormone and maintains developmental signals that prevent normal progression to a reproductive adult. Exposure of eggs and larvae interferes with embryonic development or metamorphosis, reducing successful adult emergence. This action complements adulticides, which kill existing adult fleas through separate targets, and gradually reduces replenishment of the infestation.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Flea life-cycle control | Reference only | TOPICAL | Frontline Combo Dog S: one whole 0.67 mL pipette for dogs over 2 and up to 10 kg, at least 8 weeks old. Contains 67 mg fipronil plus 60.3 mg (S)-methoprene. Minimum retreatment interval 4 weeks; use parasite-directed reassessment. |
Indications
- Prevention of flea egg development and larval maturation on dogs or cats using an indicated combination product.
- Environmental suppression of immature flea populations with an appropriate premises product.
- Adjunctive interruption of the flea life cycle during management of recurrent infestation or flea-allergy dermatitis.
Contraindications
- Hypersensitivity
- Use of dog-only combination on an unapproved species
- Puppies under 8 weeks for Frontline Combo
- Dogs below 2 kg for Frontline Combo
- Rabbits
Adverse effects
- Combination-dependent local irritation
- Salivation after licking
Toxicity
Manage the full formulation exposure; toxicity cannot be attributed only to the growth-regulator component.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Frontline Combo Dog S 67 mg/60.3 mg spot-on Whole 0.67 mL pipette for dogs >2–10 kg and at least 8 weeks; minimum retreatment interval 4 weeks. Not for rabbits or cats; no component-based dosing. | Other | s methoprene 60.3 mg / 0.67 mL + fipronil 67 mg / 0.67 mL | TOPICAL |
Monitoring and Administration
Use complete species- and weight-matched pipettes. Do not calculate a fractional combination pipette from the (S)-methoprene content alone.
Environmental flea control and treatment of other affected animals are important for persistent infestations.
Some (S)-methoprene products contain permethrin or phenothrin; feline safety must be judged from the complete combination, not the growth regulator alone. Do not apply to eyes or mucous membranes.
(S)-Methoprene is degraded by ultraviolet light; protect unused product from light. Skin irritation or hypersensitivity is possible even though mammalian toxicity of the growth regulator alone is low.