I also have been getting calls from this number. I also do work for Target. I find it odd though that we have not heard about this through the normal work channels of communication.

I called this phone number, after I had a long (silent) voice message on my phone from this number.  It claims to be "The Target Pharmacy Medication Management Services Line".  I stayed on hold for a long time to speak with someone and no on ever picked up, odd that all of their reps were busy.  Odd thing is I work for Target and have never had a phone call like this before, I am going to bring this information to the appropriate people at work and see if this is legit.