When should parenteral iron be considered for PN patients?

• A. When oral iron is ineffective or not tolerated
• B. When ferritin is high
• C. Immediately upon PN initiation
• D. When PN is discontinued

Answer: (A)

In PN patients, the need for iron is best addressed by the route that actually delivers iron when the gut cannot reliably supply it. Oral iron won’t help if absorption is poor or if the patient can’t tolerate it because of GI side effects or ongoing inflammation. In that situation, parenteral (IV) iron allows true repletion by bypassing the gut. A high ferritin argues against iron deficiency and can reflect inflammation or iron overload, so it isn’t a signal to give IV iron. Starting iron immediately when PN begins isn’t appropriate for everyone; you should assess iron status and tolerance first. And once PN is stopped, there’s no ongoing PN-derived iron to supplement. So the best indication for parenteral iron is when oral iron is ineffective or not tolerated.