Nihon Eisai is a pharmaceutical company operating in terms of R&D, manufacturing, distribution and marketing, with a strong focus on manufacturing and marketing of pharmaceutical drugs, over-the-counter drugs and pharmaceuticals production systems and equipment. Eisai's leading prescription drugs are Aricept® (donepezil hydrochloride), for treating Alzheimer's disease and Pariet®/AcipHex® (rabeprazole sodium), a proton pump inhibitor for treating peptic ulcers. The company is managing the product life cycle of Aricept through the development of new formulations and additional indications such as dementia associated with Parkinson’s disease and severe Alzheimer’s disease.