I'm on Tri-Sprintec, is it necessary to take the last week of 'inactive' pills?

No it isnt required to take them. They are a sugar pill and are just to keep you on track to remember to take them always once a day at the same time, I am sure you are ok, Not to worry, just remember to take them the rest of the three weeks and you are good to go. :>) Peace

I just skipped the last week of pills and i got my period later then i should have and will have it twice now. i would just take them. Plus the pharmacy wont give you your next packs if you go too early to get the prescription filled.