A medicated module for an injection system to co-deliver at least two medicaments is disclosed where a primary delivery device containing a primary medicament accepts a medicated module containing a single dose of a secondary medicament and where both medicaments are delivered through a single hollow needle. The medicated module is configured so that it will first deliver both the primary and secondary medicaments and then, if needed, a dose(s) of additional primary medicament. The module also contains a needle guard that locks the first dose delivery, but can be manually overridden by a user to perform a second or subsequent injection of primary medicament.