A pen needle assembly is provided herein which includes: a hub having a bodywith a transverse wall； an arrangement, disposed on the hub proximally of thetransverse wall,for mounting the hub onto an injector； a first needle cannula extendingdistally from thetransverse wall, the first needle cannula terminating at a distal end, formedfor insertion into apatient, with a first lumen extending proximally from the distal end, thefirst needle cannulabeing of a first gauge； and, a second needle cannula extending proximally fromthe transversewall, the second needle cannula extending from a distal end and terminating ata proximal endwith a second lumen extending distally from the proximal end. The first andsecond lumens arein communication. Further, the second needle cannula is of a second gauge, thesecond gaugedefining a larger external cross-section than the first gauge. Advantageously,with the subjectinvention, two needle cannulas may be arranged in series of different gauges.This permits useof a thinner gauge needle cannula for injection into a patient with a largergauge, more rigid,needle cannula being provided for accessing a drug cartridge or otherreservoir.
