Nested blunt/sharp injection assembly

Abstract

An injection device is provided which avoids the problems of coring, needle dulling, and accidental needle sticks which can occur when a conventional sharp hypodermic needle is used to access a medication vial. In this device a conventional sharp hypodermic needle having a conventional syringe attachment such as a Luer Lok adapter is nested inside a specially adapted blunt cannula which is provided with a sharp vial access tip. The above assembly is enclosed by a removable protective sheath, to protect the vial access tip and blunt cannula (as well as the sharp administration needle nested inside the blunt cannula) before and during use. In use, the protective sheath is removed and the vial access tip is used to penetrate the elastomeric stopper which conventionally seals a medication vial, thus protecting both the blunt cannula and the sharp needle from contact with the elastomeric stopper. The vial access tip can be removable, so that it remains behind in the medication vial after the syringe has been filled and the blunt cannula removed. The user can then selectively use either the blunt cannula or the sharp needle for administration of the medication. If the sharp needle is desired, the blunt cannula can be removed by replacing the protective sheath and engaging a locking mechanism between the protective sheath and the blunt cannula for separating the blunt cannula from the needle hub, thus exposing the sharp needle.