No adverse reaction has been recorded between Sentinel and other flea medicine. If you have a problem only with fleas my advice is to use Advantage for protection because it has only one active ingredient (imidacloprid). See below some more information about the product:
For the prevention and treatment of flea infestations on cats and dogs, and for the treatment of biting lice (Trichodectes canis) on dogs.
For the treatment of flea infestations on pet rabbits.
Fleas are killed within one day following treatment. One treatment prevents further flea infestation on dogs for up to four weeks, three to four weeks on cats and up to one week on pet rabbits. The product can be used as part of a treatment strategy for flea allergy dermatitis in the cat and the dog. The treatment should be repeated after 4 weeks.(Dogs) In case of biting louse infestation, a further veterinary examination 30 days after treatment is recommended as some animals may require a second treatment.
Imidacloprid is an ectoparasiticide belonging to a group of chloronicotinyl compounds. Chemically, it is more accurately described as a chloronicotinyl nitroguanidine.
Imidacloprid has a high affinity for the nicotinergic acetylcholine receptors in the post-synaptic region of the central nervous system (CNS). The ensuing inhibition of cholinergic transmission in insects results in paralysis and death. Due to the weak nature of the interaction with mammalian nicotinergic receptor sites and the postulated poor penetration through the blood/brain barrier in mammals, it has virtually no effect on the mammalian CNS. The minimal pharmacological activity in mammals is supported by safety studies involving systemic administration of sub-lethal doses to rabbits, mice and rats.
Oral studies in the rat show imidacloprid to be absorbed rapidly from the gastro-intestinal tract. Almost complete absorption (95%) occurs within 48 hours. Peak plasma concentrations are observed within 2.5 hours following administration. Tissue distribution is also rapid with the lowest levels recorded in the brain. The active ingredient undergoes extensive metabolism with only 10-16% remaining as parent compound. Almost complete (96%) elimination occurs within 48 hours, approximately 75% being removed by the kidneys and 21% with the faeces.
Please read the leaflet enclosed with the product.