That's possible, but extraordinarily unlikely. NH3 is passively taken up across membranes, not by active transport that could be inhibited.
Curiously, there is NO published data anywhere (at least that we have found) demonstrating that Prime actually works to reduce toxicity of ammonia, nitrite or nitrate.
Such a mechanism would also make Seachem liars for claiming what they do. They do not just claim reduced toxicity, they explicitly state how it does so.
Seachem has a very low threshold for making claims that something works.
They claim it detoxifies nitrate, but when you read carefully they say they do not know how tha tmight happen, but some users report it.
OMG, good enough for me! By all means claim:
" It contains a binder which renders ammonia, nitrite, and nitrate non-toxic,"
without ANY supporting data or understanding at all.
www.seachem.com
"I wish we had some more "concrete" explanation, but the end result is the same, it does actually detoxify nitrite and nitrate. This was unexpected chemically and thus initially we were not even aware of this, however we received numerous reports from customers stating that when they overdosed with Prime® they were able to reduce or eliminate the high death rates they experienced when their nitrite and nitrate levels were high. We have received enough reports to date to ensure that this is no fluke and is in fact a verifiable function of the product."