Single and multiple dose pharmacokinetics of enteric coated ketoprofen: effect of cimetidine

The effect of cimetidine on the single and multiple dose pharmacokinetics of enteric coated ketoprofen was studied in 12 healthy volunteers. Each subject completed two 8-day study treatment periods: either ketoprofen alone (100 mg p.o. twice daily), or co-administered with cimetidine (600 mg twice daily). tlag, Cmax, tmax, t1/2, and k for ketoprofen were not significantly different between single and multiple dose administration. AUC of ketoprofen was slightly but significantly larger following multiple (21.2 micrograms.h.ml-1) as compared to single dose administration (19.0 micrograms.h.ml-1). As a result, plasma clearance of ketoprofen was slightly but significantly reduced following multiple dose administration (80.6 ml/min vs 89.3 ml/min). Cimetidine had no effect on the single or multiple dose pharmacokinetics of enteric coated ketoprofen. Total 12-h urinary recovery of ketoprofen (mostly in the form of ketoprofen glucuronide) was 83.5% of the dose following single dose administration and was significantly greater following multiple dose administration (93.1%). Again cimetidine co-administration had no effect on the single and multiple dose urinary recovery. The results of this study show that cimetidine is not affecting the oral pharmacokinetics of enteric coated ketoprofen.