A medication injection pen (51) includes a housing (1) and a dose set knob (2)having at least one internal tooth(22). A brake member (5) has a plurality of axially extending splines (52). Adriver or setback member (9) includesat least one external tooth (92) engaging the at least one internal tooth (22)of the dose set knob (2) and at leastone ratchet arm (96) engaging the plurality of axially extending splines (52).The driver (9) is prevented fromrotating with the dose set knob (2) while moving axially with the dose setknob (2) during dose setting and dosecorrecting, and the driver (9) rotates with the dose set knob (2) during aninjection.
