I don’t know if you know this or even if I have it right, but it seems that Rabbi Blumenkrantz’s book is just listing the particular manufacturers of the generic. Is there any way for you to find out which manufacturer made the particular generic pills that you have? If it’s not on the pill, you can probably call the pharmacist and ask. Otherwise, ask a Rov. I would be surprised if there’s any reason not to take them since it’s obvious that the actual chemical doesn’t involve chometz, since Rabbi Blumenkrantz certifies it from another manufacturer.
ETA: TL;DR – what everyone else said, but less comprehensible.