Pyriprole
Pyriprole is a phenylpyrazole antiparasitic agent used for the **treatment and prevention of flea infestations** (*Ctenocephalides canis*, *C. felis*) and **tick prevention** in dogs. It is applied topically as a spot-on solution. > **Clinical Warning:** Do not use on cats. Safety has not been established in pregnant and lactating females, or in dogs under 8 weeks of age or weighing less than 2 kg.
Mechanism: Pyriprole acts by interacting with **ligand-gated (GABA) chloride channels**, blocking the pre- and post-synaptic transfer of chloride ions → leading to hyperexcitation of the central nervous system and subsequent death of the parasites.
Dosing by species
- Fleas and ticks · minimum dose 12.5 mg/kg · topical · q4wk · For large dogs, the 5 ml dose should be applied in 2-3 spots.
- Contraindicated · Do not use. · topical · Strictly contraindicated in cats.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Cats
- Pregnant and lactating females (safety not established)
- Dogs < 8 weeks of age
- Dogs < 2 kg body weight
Adverse effects
- Pruritus/dermatitis at application site
- Lethargy
- Ataxia
- Convulsions
- Emesis
- Diarrhoea
Monitoring
- Efficacy of flea and tick control
- Application site reactions
- Neurological signs (ataxia, convulsions)
Overdose
No specific information available in the monograph. Overdose may exacerbate known adverse reactions such as neurological signs (ataxia, convulsions) and gastrointestinal upset (emesis, diarrhoea). Treat symptomatically.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.