I am completely finished with my rx iron 325 mg, but need more. will the same strength otc non-rx iron (ferrous sulfate) work just the same? yes? no?

Depending on the: level of iron deficiency anemia you have, you would need between 160 mg to 480 mg of iron sulfate (there are other compounds) daily. Your body can only absorb so much through the gut before inducing side effects. Most OTC iron preparations are between 5 mg to 65 mg, so likely you would have to take a lot of pills to make up for the deficiency. The key is to have regular checkup to see progress