I just did a quick search, and I found that apap is immediate release and hci is controlled release. I'm sure Jim will be here soon to help out. Also hci has aspirin. Don't know about apap. Tough to find stuff, since all the 'Get Drugs With No Prescription' sites keep coming up LOL. I would think substituting one for another has serious consequences, since they both react differently in their dosing.

Marmar