The application discloses a drug infusion system comprising a base and a drug dispenser. The base is configured to receive a cannula that delivers a drug to beneath a wearer's skin. The base is attachable to the skin of the wearer. The reusable drug dispenser is removably attachable to the base and has a pump unit configured to establish fluid communication between a removably attachable drug reservoir and the cannula. The pump unit pumps the drug to the wearer upon activation by the wearer. The pump unit may have an inlet to contact the drug within the reservoir, which may be a needle. The pump unit may also have a receiving unit to receive the reservoir. Such a receiving unit may be a tubular for a cylindrical reservoir, or may have a cavity or an encasing unit to hold the reservoir.