A drug delivery device includes a housing defining a shell and an inner volume, a container, a drive mechanism, a needle assembly, a fluid flow connection, and a backflow prevention mechanism. The container has an inner volume to contain a medicament to be administered to a user. The drive mechanism is at least partially disposed within the housing and exerts a force to urge the medicament out the container. The fluid flow connection is coupled to the container and the needle assembly and allows the medicament to flow from the container to the needle assembly to be administered. The backflow prevention mechanism is associated with at least one of the container, the fluid flow connection, or the needle assembly and includes at least one flow restrictor to restrict a fluid from flowing from the needle assembly to the container.