Clarify limitations of alternate-day oral iron dosing

Is it better to take oral iron supplements every other day? ㅡ Not really. Some recent evidence suggests giving doses every OTHER day increases the amount of oral iron absorbed by up to 50%. Unabsorbed iron is thought to be the culprit for GI side effects.

It's no surprise that DIVIDING the daily iron dose every other day seems to cause less nausea. But giving the same TOTAL dose every other day does NOT seem to limit GI side effects. And it turns out that increased iron absorption does NOT mean patients can take less iron. Explain that it may take twice as long to correct iron deficiency if doses are divided every other day. Plus, irregular dosing may impair adherence at home. When hospitalized patients need oral iron to treat iron deficiency, don't go to alternate-day dosing.

Continue to start with ferrous sulfate one tab daily for most patients. Most products have 65 mg elemental iron/tab which is often enough for iron deficiency or mild anemia. Schedule oral iron to be taken on an empty stomach for the best absorption. But it's okay to take with food if nausea occurs.

Don't rely on vitamin C for help. Clarify that 200 mg, or 8 oz of orange juice, only increases iron absorption about 10%. Limit PPIs or H2-blockers and space antacids several hours from iron doses, these may decrease iron absorption. Continue to rely on IV iron for patients with chronic kidney disease, recent blood loss, or severe anemia. And consider other indications where IV iron may be beneficial such as inflammatory bowel disease, post bariatric surgery, or certain acute heart failure patients.

References

• Stoffel, N.U., Zeder, C., Brittenham, G.M., Moretti, D. and Zimmermann, M.B. (2019). Iron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient anemic women. Haematologica, 105(5), pp.1232–1239. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7193469

  Kaundal R, Bhatia P, Jain A, Jain A, Nampoothiri RV, Mishra K, Jandial A, Goni D, Sandal R, Jindal N, Meshram A, Sharma R, Khaire N, Singh C, Khadwal A, Prakash G, Das R, Varma N, Varma S, Malhotra P, Lad DP. Randomized controlled trial of twice-daily versus alternate-day oral iron therapy in the treatment of iron-deficiency anemia. Ann Hematol. 2020 Jan;99(1):57-63. Available at: https://pubmed.ncbi.nlm.nih.gov/31811360

  Stoffel NU, Cercamondi CI, Brittenham G, Zeder C, Geurts-Moespot AJ, Swinkels DW, Moretti D, Zimmermann MB. Iron absorption from oral iron supplements given on consecutive versus alternate days and as single morning doses versus twice-daily split dosing in iron-depleted women: two open-label, randomised controlled trials. Lancet Haematol. 2017 Nov;4(11):e524-e533. Available at: https://pubmed.ncbi.nlm.nih.gov/29032957