A pen needle assembly is provided herein which includes: a hub having a body with a transverse wall； an arrangement, disposed on the hub proximally of the transverse wall, for mounting the hub onto an injector； a first needle cannula extending distally from the transverse wall, the first needle cannula terminating at a distal end, formed for insertion into a patient, with a first lumen extending proximally from the distal end, the first needle cannula being of a first gauge； and, a second needle cannula extending proximally from the transverse wall, the second needle cannula extending from a distal end and terminating at a proximal end with a second lumen extending distally from the proximal end. The first and second lumens are in communication. Further, the second needle cannula is of a second gauge, the second gauge defining a larger external cross-section than the first gauge. Advantageously, with the subject invention, two needle cannulas may be arranged in series of different gauges. This permits use of a thinner gauge needle cannula for injection into a patient with a larger gauge, more rigid, needle cannula being provided for accessing a drug cartridge or other reservoir.
