Two-echelon supply chain model consists of two separate components that have diverse objectives. In this study, a supply chain is modelled as a two-echelon supply chain consisting of one supplier, one retailer and one product at a pharmaceutical supply chain. The purpose of optimization is to maximize the total profit generated during sales and distribution of the product. Sales take place at the pharmaceutical retailer and the demand encountered is stochastic, and order periods are determined by the frequency of visits by the drug supplier. Considering this visit frequency, the pharmaceutical retailer uses a periodic review inventory system. For the retailer, the decision variable is the safety factor which is determined according to the selected order level and determines the pharmaceutical supplier profitability by affecting the sales volume of the Pharmaceutical Supply Chain. The problems optimized with two different scenarios and two different models which are the traditional supply chain model, and the two-echelon supply chain model. Heuristic model of these problems provides more profitability for both echelons. With this study it is understood that genetic algorithm can be used for two echelon pharmaceutical supply chain and gives better results than mathematical model of the same problem.