PGP and epilepsy: The results indicate that prolonged seizures induce the appearance of P-gp over-expression in the brains of dogs, which may explain why delaying the start of treatment in the state of epilepsy leads to a decrease in the effectiveness of anticonvulsants, and may also be a mechanism contributing to the development of resistance to treatment in dogs with epilepsy, which affects about 20–40% of them [26].