The present study was aimed to investigate the effect of piperine, a major active ingredient of black pepper, on the pharmacokinetics of domperidone in rats. Animals were given oral (p.o.) or intraperitoneal (i.p.) domperidone (20 mg/kg) alone or together with piperine (20 mg/kg, p.o.). Plasma samples were collected at 0.25, 0.5, 1.0, 2.0, 3.0, 4.0, 6.0, 8.0, 10.0 and 12 hours after drug administration. The concentration of domperidone in the plasma was measured using a HPLC method. The concomitant administration of piperine with oral or intraperitoneal domperidone resulted in a significant (P<0.05) increase in the maximum plasma concentration (Cmax), the mean area under the plasma concentration-time curve (AUC), and the elimination half-life (t1/2) of domperidone as compared to those obtained for domperidone alone. These results suggest that an important pharmacokinetic interaction may occur if piperine is administered concurrently with domperidone.
