Parkinson’s Disease (PD) is the second most common neurodegenerative disorder in the world after Alzheimer’s. The hallmark symptoms of PD are tremor and rigidity, which are caused by the death of dopaminergic neurons, specifically within the substantia nigra of the basal ganglia. These symptoms are often treated by Levodopa (L-DOPA), MAO-B inhibitors, and other pharmaceuticals with the goal of increasing the dopamine concentration in the brain. To better understand how L-DOPA impacts the brain’s dopamine dynamics, various computational models have been developed. One model, by Véronneau-Veilleux et al. (Chaos 30, 093146, 2020), integrates L-DOPA pharmacokinetics, dopamine dynamics, and a neurocomputational model of the basal ganglia to predict the impact of L-DOPA regimens on a patient\u27s motor function. In this study, we extended the model to investigate an adjunct therapy of L-DOPA with the MAO-B inhibitor Rasagiline utilizing an enzyme inhibition model, which showed a 1.67% increase of dopamine concentration in the brain when compared to L-DOPA therapy alone. Our model provides a foundation for optimizing treatment strategies using both L-DOPA and an adjunct