Pharmaceutical providers are now facing problems such as counterfeit drugs, lack of openness, different data systems, and weaker regulation. As a result of these shortcomings, medicinal products may be unsafe for patients and this can damage the public's trust in these products. Traditional centralized structures do not have the necessary traceability, security, and resilience for effective management of supply chains. In the context of Industry 4.0, there is an increasing shift toward digital transformation and decentralized industrial systems to improve transparency and automation. This paper describes PharmaChain, a DApp created using blockchain, which is intended to add transparency and trust to the way drugs are managed in the supply chain. With the help of Ethereum and Solidity-based smart contracts, PharmaChain develops a permanent record of every step in the supply chain, starting with buying raw goods and finishing with delivering them to end-users. The platform uses role-based access control, such as manufacturers, distributors, retailers, and regulatory bodies. With a modern MERN stack, PharmaChain ensures the UI is flexible and works well on any device, and Web3.js and MetaMask handle the connection to blockchain on the frontend. The proposed system aligns with Industry 4.0 principles by enabling secure, automated, and decentralized traceability across the pharmaceutical supply chain. Smart contracts significantly reduce the involvement of intermediaries and manual work in the process.