How Long Does It Take For Norco To Work In Your System? Norco takes around 10 to 30 minutes to kick in. Its peak effects take around 30 minutes to an hour to set in. Norco doesn't start working immediately because the drug is taken by mouth and needs to dissolve in your GI tract before it gets into your bloodstream. Norco(hydrocodone bitartrate and acetaminophen) is a prescribed pain relief medication which is used to treat oral administration. You...