Pharmacokinetics of flupirtine in elderly volunteers and in patients with moderate renal impairment

Abstract

Summary:The pharmacokinetics of flupirtine after a single oral dose of 100mg have been studied in patients with moderate renal impairment and in healthy elderly subjects aged 66-83 years. Mean elimination half-life of flupirtine was higher in elderly patients than in younger normal subjects, and this was associated with an increased maximum serum concentration and reduced clearance. The mean half-life in patients with renal impairment was higher than in normal subjects.There was no correlation between observed elimination half-life and degree of renal impairment, but the creatinine clearance of most patients fell in a narrow range between 43 and 60 ml/min. In the light of these results and until further information is available, it would be prudent to start treatment of patients who are elderly or have evidence of renal impairment with half the dose of flupirtine recommended for younger patients with normal renal function.

Pharmacokinetic profiles of the analgesic flupirtine in dogs after the administration of four pharmaceutical formulations

“…The T max after POIR in dogs (1.42 hours) is similar to that reported for humans (range 1.6–1.8 hours) (Abrams et al. ) and is shorter than that found in cats (2.78 hours) (De Vito et al. ).…”

“…These values were in line with the mean terminal plasma elimination half‐life in healthy humans which was reported to be approximately 6.5 hours (Abrams et al. ), whereas they were about half of the half‐life observed in cats (13.6 hours) (De Vito et al. ).…”

Pharmacokinetic profiles of the analgesic drug flupirtine in cats

“…This difference could be attributed to a number of potential reasons including the large variation in this parameter in the cat, different efficacy of absorption or other species-specific factors. In contrast, the FLU plasma maximal concentrations after PO route in humans (100 mg/subject) and in cats (5 mg/kg) were comparable if normalized for the administered dose (770 ng/mL vs. ng/mL) (Abrams et al, 1988). A large difference between humans and cats has been shown in oral F%.…”

“…Although the CL value of FLU did not significantly change in patients with mild renal impairment compared to healthy patients, the half-life almost doubled (Abrams et al, 1988). Hence caution should be used in cats with presumed renal impairment.…”

“…Hence caution should be used in cats with presumed renal impairment. It has also been proven that old age is associated with increased half-life of the drug in humans (Abrams et al, 1988) and this should be taken into consideration if FLU is to be administered to elderly cats.…”