Designing sustainable Pharmaceutical Supply Chain (PSC) networks, while accounting for reverse flows and operational realities, represents an emerging challenge in healthcare supply chain management. This research develops a multi-objective mathematical model that simultaneously addresses facility location, Third-Party Logistics (3PL) provider selection, integration of distribution centers (for both forward and reverse logistics), and pharmaceutical return policies (donation vs. resale). The innovation of this model lies in the dynamic selection between in-house facilities and 3PL warehouses, the integration of return policies, and the strategic decision-making regarding the multi-purpose functionality of distribution centers. The model is solved using the epsilon-constraint method, revealing a Pareto front among the objectives of profitability, environmental sustainability, and job creation. Specifically, total profit ranges from 750 to 950 monetary units, CO2 emissions vary between 130 and 310 units, and job creation fluctuates between 100 and 120 positions. Scenario analysis demonstrates that implementing a hybrid return policy leads to a 17% reduction in pharmaceutical waste and a 5% increase in profit compared to a donation-only approach. Furthermore, the utilization of 3PL warehouses in 60% of cases has successfully reduced capital expenditure for warehouse construction while increasing the rate of multi-purpose distribution center utilization by up to 50%.