Since the 1940s, antimicrobials have been used to combat microbial infections and sickness enormously. However, due to the overuse and abuse of antimicrobials, antimicrobial resistance has been exacerbated resulting in side effects. The microbes have developed resistant mechanisms towards antimicrobials making these drugs less effective (Soni, 2014). Antimicrobial resistance reduces the effectiveness of an antimicrobial in curing a disease or condition. In order to combat the increasing rate of antimicrobial resistance, new strategies are needed; hence researchers are looking into using combination therapy to combat AMR. This research envisages treating infections with different combinations and/or sets of drugs rather than individual drugs. Nucleoside analogues are commonly used for treating viral and fungal infections, as well as for treating cancers, however, a significant number of clinically approved derivatives of both pyrimidines and purines have been shown to have antibacterial activity. In view of this, this experiment will be conducted to determine the drug interactions between the methylxanthines and antimicrobials to find out their potential antimicrobial properties in an attempt to repurpose these drugs. The method employed includes drug preparation and antibiotic/fungal preparations, determination of their minimum inhibitory concentration and the determination of their drug interactions with the antimicrobials by disc diffusion bioassay. For the results, it is envisaged that interactions between the xanthine-based drugs and the antibiotics or antifungals may potentiate the activity, have no significant effect on the activity and/or suppress the activity of antibiotics and antifungals against the selected bacterial and fungal culture.