SYNERGISTIC DRUG-DRUG INTERACTION;

Introduction: Ranitidine is known to us all as an anti-ulcer drug which acts byblocking H2 receptors in the stomach parietal cells. However its role in this category has beenunderstated. We studied its prokinetic effect on isolated duodenum of rabbits and its synergisticinteraction with Levosulpiride. The purpose of the study was to see if the two drugs do have aprokinetic effect and whether the combined effect is greater than the individual drugs. StudyDesign: Laboratory based Randomised controlled trial. Period: November 2014 to November2015. Setting: The study was carried out in the multidisciplinary laboratory at Army MedicalCollege after approval from Animals ethics committee. Material and methods: Dose responsecurve was constructed using cumulatively increasing concentrations of Ranitidine (Group 1)and Levosulpiride (Group 2). The synergistic prokinetic drug-drug interaction of Ranitidine andLevosulpiride was observed in Group 3 on iWorx Data acquisition unit (PowerLab). Resultsand Conclusion: Ranitidine produced a dose dependent reversible contraction of the isolatedduodenum and the maximum effect was recorded at 35 μg as 0.136 mV. Levosulpiride produceda maximum contraction of 0.088 mV at 70 μg. Ranitidine and levosulpiride curve was shifted tothe left and upwards of levosulpiride alone. The percent responses of levosulpiride alone was90 percent and with ranitidine was 122 percent. Ranitidine and levosulpiride have a synergisticprokinetic interaction in vitro. Conclusion: Ranitidine and levosulpiride have a synergisticprokinetic drug-drug interaction in vitro.