In Brazil, medicine dispensing is a pharmacy service provided within the national health system that allows the pharmacist to interact directly with the patient in order to prevent, detect and solve problems related to pharmacotherapy and health needs. However, it is known that most dispensing services provided in the country are still limited to supplying medications and, at their finest, offering advice on medication utilization. Attempts to change this scenario present new challenges the area of pharmacy, which involve the need for a patient-centered pharmaceutical service model. This paper describes the patient-centered pharmaceutical service of high-cost medicine dispensing performed at a pharmacy linked to the Brazilian Unified Health System. In the model described here, the medicine-dispensing activity is the pharmacist's main field of practice, which consists of identifying patient needs related to health care itself and medication utilization. It also aims to introduce the instrument developed (a Pharmaceutical Care Protocol) that contributed to implementing this clinical service provided by the pharmacist. The protocols guide and qualify the service by providing information that helps in evaluating the effectiveness and safety of treatments and in the preparation of the care plan and can be used as a basis for other services that intend to adopt clinical pharmacy practices.