Alternate-day versus once-daily oral iron for iron deficiency anemia

Alternative vs. Once-Daily Oral Iron Supplementation in Iron Deficiency Anemia (IDA): A Multicenter, Randomized, Open-Label, Non-Inferiority Trial

This study will test whether taking ferrous fumarate every other day works as well and causes fewer side effects than taking it once daily for adults with iron deficiency anemia.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 114 (estimated)
• Ages: 20 Years and up
• Sex: All
• Sponsor: Phramongkutklao College of Medicine and Hospital (Academic / other)
• Locations: 1 site (Bangkok)
• Trial ID: NCT07014371 on ClinicalTrials.gov

What this trial studies

This is a randomized, open-label, non-inferiority trial comparing two oral ferrous fumarate regimens in adults with iron deficiency anemia. Participants are assigned to either 200 mg once daily or 400 mg on alternate days for 8 weeks, with blood tests and clinical assessments at baseline, Week 4, and Week 8. The trial measures hematologic response (hemoglobin and iron indices), side effects, and medication adherence to see if alternate-day dosing provides similar benefit with better tolerability. The multicenter design aims to capture real-world adherence and adverse event profiles.

Who should consider this trial

Good fit: Adults aged 20 years or older with iron deficiency anemia (low hemoglobin and low ferritin or transferrin saturation) who have not taken iron supplements in the past 3 months are the intended participants.

Not a fit: Patients with severe cardiac disease, advanced liver or kidney disease, active malignancy, significant thalassemia/hemoglobinopathies, malabsorption, pregnancy or breastfeeding are unlikely to be eligible or to benefit from this trial.

Why it matters

Potential benefit: If successful, alternate-day dosing could correct anemia as effectively while reducing gastrointestinal side effects and improving adherence.

How similar studies have performed: Previous research has suggested alternate-day oral iron can improve absorption and reduce GI side effects compared with daily dosing, but findings have varied and more rigorous comparisons are ongoing.

Eligibility criteria

Inclusion Criteria:

* Male or female patients aged ≥20 years diagnosed with iron deficiency anemia, defined as: hemoglobin (Hb) \<13 g/dL in males or \<12 g/dL in females, and ferritin \<50 ng/mL or transferrin saturation (TSAT) \<20%.
* No iron supplementation within the past 3 months.

Exclusion Criteria:

* Hemodynamic instability (e.g., acute bleeding or hypotension).
* Severe heart failure (New York Heart Association \[NYHA\] Class III-IV) or other active cardiac diseases.
* Active malignancy or history of cancer within the past 3 years (except non-melanoma skin cancer).
* Pregnancy or breastfeeding.
* Chronic liver disease including cirrhosis (Child-Pugh class B or C).
* Chronic kidney disease (estimated glomerular filtration rate \[eGFR\] \<60 mL/min/1.73 m²).
* Clinically significant thalassemia or hemoglobinopathies.
* Ongoing infection or chronic inflammatory diseases (e.g., rheumatoid arthritis, inflammatory bowel disease).
* Malabsorption disorders (e.g., history of bariatric surgery).
* Red blood cell transfusion within the past 3 months.

Withdrawal Criteria

* Withdrawal of informed consent.
* Severe adverse events requiring permanent discontinuation of study medication.
* Investigator's judgment that continued participation poses a safety risk.
* Non-adherence to study medication (compliance \< 75%).

Treatment Failure

\- Increase in hemoglobin level of \< 1 g/dL at Week 4 or Week 8 compared with baseline.

Where this trial is running

Bangkok

• Phramongkutklao Hospital — Bangkok, Thailand (Recruiting)

Study contacts

• Study coordinator: Tanapun Thamgrang, Doctor of Medicine

Conditions Iron Deficiency Anemia Treatment; Iron deficiency anemia; Ferrous fumarate; Alternate day dosing; Hemoglobin