SYNERGISTIC DRUG-DRUG INTERACTION;

RANITIDINE AND LEVOSULPIRIDE-IN VITRO

Abstract

Introduction: Ranitidine is known to us all as an anti-ulcer drug which acts by
blocking H2 receptors in the stomach parietal cells. However its role in this category has been
understated. We studied its prokinetic effect on isolated duodenum of rabbits and its synergistic
interaction with Levosulpiride. The purpose of the study was to see if the two drugs do have a
prokinetic effect and whether the combined effect is greater than the individual drugs. Study
Design: Laboratory based Randomised controlled trial. Period: November 2014 to November
2015. Setting: The study was carried out in the multidisciplinary laboratory at Army Medical
College after approval from Animals ethics committee. Material and methods: Dose response
curve was constructed using cumulatively increasing concentrations of Ranitidine (Group 1)
and Levosulpiride (Group 2). The synergistic prokinetic drug-drug interaction of Ranitidine and
Levosulpiride was observed in Group 3 on iWorx Data acquisition unit (PowerLab). Results
and Conclusion: Ranitidine produced a dose dependent reversible contraction of the isolated
duodenum and the maximum effect was recorded at 35 μg as 0.136 mV. Levosulpiride produced
a maximum contraction of 0.088 mV at 70 μg. Ranitidine and levosulpiride curve was shifted to
the left and upwards of levosulpiride alone. The percent responses of levosulpiride alone was
90 percent and with ranitidine was 122 percent. Ranitidine and levosulpiride have a synergistic
prokinetic interaction in vitro. Conclusion: Ranitidine and levosulpiride have a synergistic
prokinetic drug-drug interaction in vitro.