PHARMACOKINETICS OF FLUPIRTINE IN DOGS AND CATS

Introduction Flupirtine (FLU) is a non-opiod analgesic drug belonging to the class of N-methyl-D-aspartate. In human medicine FLU is recommended for the treatment of a wide range of pain states, but no study has been performed in pets. Aim of the study To evaluate the pharmacokinetic profiles (PK) of FLU in healthy dogs and cats after different routes of administrations. Material and method Animals: Six healthy Labrador breed adult dogs and six healthy mixed breed adult cats were used in two different experiments. Dogs: single-dose, four-group and four-treatment (intravenous IV, oral immediate release POIR, per rectum RC routes [5 mg/kg]; oral prolonged release POPR [200 mg/subject]), crossover design. Cats: single-dose, two groups, two treatments (IV and POIR [5 mg/kg]), crossover design. The wash out period was 1-week between trials. Blood samples were collected at assigned times and plasma was analysed by a validated HPLC method. Results Some adverse effects, rapidly resolved, were noted only in dogs after IV treatment. The FLU plasma concentrations were detectable in all groups up to 36 h. The bioavailability (F%) values after POIR, POPR and RC in dogs were 41.9, 36.8 and 29.3% respectively, while oral F% in cats was 39.3 ± 9.7%. Oral F% in both dogs and cats was similar, but about two times smaller than that found in humans (90%). This large differences demonstrated that PK values derived in pets should not be extrapolated to humans, and vice versa. Conclusion This study represents the first step that should pave the way for use of this active ingredient in the veterinary field.