What is the most suitable oral iron supplement for a gynecology (GYN) patient with chronic anemia who has difficulty swallowing pills, preferably a chewable option that minimizes constipation and gastrointestinal (GI) side effects while optimizing absorption?

From the Guidelines

For a gynecological patient with chronic anemia who cannot swallow pills and needs a chewable iron option with minimal constipation and GI side effects, I recommend ferrous bisglycinate (iron bisglycinate) chewable tablets, as they are better absorbed and cause less constipation, nausea, and stomach pain compared to traditional iron salts, as suggested by recent clinical practice updates 1. These typically come in 25-30 mg elemental iron per tablet, and patients should take 1-2 tablets daily with vitamin C-containing food or drink to enhance absorption, as adding vitamin C to oral iron supplementation improves absorption 1. Ferrous bisglycinate is a chelated iron that bypasses the typical iron absorption control mechanisms in the gut, allowing for better bioavailability even at lower doses. If ferrous bisglycinate is unavailable, carbonyl iron chewables are a reasonable alternative, though they may cause slightly more GI effects. Regardless of the form chosen, starting with a lower dose and gradually increasing can help minimize side effects, and taking the supplement with food containing vitamin C will enhance absorption, while avoiding calcium-rich foods or antacids within two hours of iron intake will prevent decreased absorption, as supported by the AGA clinical practice update on management of iron deficiency anemia 1. It's also important to note that taking oral iron once a day at most, or even every other day, may be better tolerated for some patients with similar or equal rates of iron absorption as daily dosing, as suggested by recent studies 1.

From the FDA Drug Label

Unique, Innovative Iron Supplementation System• Enhanced GI Tolerability • Improved Absorption GENTLE ON THE STOMACH The best option for a GYN patient with chronic anemia who has difficulty swallowing pills and is looking for a chewable iron supplement that does not constipate and has less GI side effects is not explicitly stated in the provided drug labels.

• Iron bisglycinate 2 and ferrous fumarate 3 claim to have enhanced GI tolerability and be gentle on the stomach, but there is no direct comparison or information on constipation or absorption rates.
• There is no information on ferrous gluconate 4 regarding GI tolerability or constipation. The FDA drug label does not answer the question.

From the Research

Iron Supplementation for GYN Patients with Chronic Anemia

• For GYN patients with chronic anemia who have difficulty swallowing pills, a chewable iron supplement may be a suitable option.
• The goal is to find an iron supplement that does not cause constipation, has minimal gastrointestinal (GI) side effects, and is well-absorbed.

Comparison of Iron Supplements

• A study published in 2024 5 compared the effectiveness and safety of different oral iron salts, including ferrous ascorbate, ferrous fumarate, ferrous bis-glycinate, and Sucrosomial iron.
• The results showed that Sucrosomial iron supplementation resulted in significantly higher improvement in hemoglobin levels and serum ferritin levels compared to conventional oral iron salts, with a better safety profile.
• Another study published in 2022 6 found that low-dose ferrous bisglycinate chelate supplementation improved serum iron concentration and transferrin saturation in patients with chronic kidney disease, with no reported GI upset events.
• A study published in 2012 7 compared the efficacy and toxicity of oral ferrous bisglycinate chelate and ferrous sulfate in cancer patients with mild iron deficiency anemia, and found that ferrous bisglycinate chelate had similar efficacy and likely lower GI toxicity than ferrous sulfate.

Ferrous Bisglycinate as a Suitable Option

• A systematic review and meta-analysis published in 2023 8 found that ferrous bisglycinate supplementation resulted in higher hemoglobin concentrations and fewer reported GI adverse events compared to other iron supplements in pregnant women.
• The review also found that ferrous bisglycinate shows some benefit over other iron supplements in increasing hemoglobin concentration and reducing GI adverse events among pregnant women.
• Based on the available evidence, ferrous bisglycinate may be a suitable option for GYN patients with chronic anemia who require a chewable iron supplement with minimal GI side effects and good absorption.

Key Considerations

• It is essential to consult with a healthcare provider to determine the best course of treatment for individual patients with chronic anemia.
• The choice of iron supplement should be based on the patient's specific needs and medical history, as well as the potential benefits and risks of each supplement.