pptu.lefora.com has a reference for different strategies. Take a look in the Dr. Cahill section. The general consensus is that longer treatment times are needed.
There is no one set of protocols that eliminate protozoa and usually they are combinations. If Nita worked then why stop that?
Usually they combine a lumicidal drug with the main drug. Furazolidone is lumicidal as is diloxanide furoate and paromoycin are the others. Diloxanide furoate is difficult to source. Nita along with Paromycin was an effective treatment combination for many.