When should iron be given intravenously?

If Hb levels are less than 10 grams per deciliter, side effects of oral supplementation are not tolerable (e.g., constipation), and/or Hb fails to rise from treatment sufficiently, intravenous iron is often prescribed. While less convenient, it can increase Hb more quickly and with less adverse reactions, which tend to include local pain, skin irritation, and allergic reactions.^[1][2]